Aircraft survivability

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Aircraft survivability
Place of Publication:
Arlington, VA
Joint Aircraft Survivability Program Office (JASPO)
Creation Date:
Summer 1998
Publication Date:
Copyright Date:
Three times a year


Subjects / Keywords:
Aeronautics -- Safety measures -- Periodicals -- United States ( lcsh )
Aeronautics -- Safety measures ( fast )
United States ( fast )
Periodicals. ( fast )
newspaper ( marcgt )
serial ( sobekcm )
periodical ( marcgt )
Periodicals ( fast )


Dates or Sequential Designation:
Began with 1998.

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Source Institution:
University of Florida
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University of Florida
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This item is a work of the U.S. federal government and not subject to copyright pursuant to 17 U.S.C. §105.
Resource Identifier:
656541464 ( OCLC )
TL553.5 ( lcc )

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Digital Military Collection


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CREW AND PASSENGER SS U RVIVABILITYCASUALTY AA SS ESSMENT AND REDU cC T ION AA T T HE 5YY E A rR M M A rR Kpage 6 OO ccupant Casualty M M & SS page 9Practical AA pproach to an II n tegrated S S u rvivabilitypage 17 AIRAIR C RARA F TTSURVIVABILITY S URVIVABILITY published by the Joint Aircraft Survivability Program Ofce13SPRING ISSUE


ASAS Journal 13 / SS P R INI N G h ttp://jaspo.csd.disa.milAircraft Survivability is published three times a year by the Joint Aircraft Survivability Program Ofce (JASPO) chartered by the US Army Aviation & Missile Command, US Air Force Aeronautical Systems Center, and US Navy Naval Air Systems Command. J ASA S P rogram Ofce 735 S Courthouse Road Suite 1100 Arlington, VA 22204-2489 Views and comments are welcome and may be addressed to the: Editor DD e nnis L L in dell Assistant Editor DD a le B B A A t kinson To order back issues of the AS Journal, please visit surviac/inquiry.aspx On the cover: A V-22 Osprey aircraft assigned to Marine Medium Tiltrotor Squadron 263 lands on the ight deck of the multi-purpose amphibious assault ship USS Bataan (LHD 5) while underway in the Atlantic Ocean on 8 July 2008. DoD photo by Petty Ofcer 3rd Class Patrick Gearhiser, US Navy. TT ABLE of OF C oO N TENTS4 NEWS NOTESby Dennis Lindell5 JCAT C ornerORNER by CAPT Bill Little, USN and LTC Chuck Larson, USAF6 C asualtASUALT Y A ssessmentS SESSMENT and AND R eductionE DUCTION A tT the THE 5YearY EAR M arA R Kby Rick SayreSince Vietnam, the Joint Aircraft Survivability Program has supported the development of critical technology that signicantly reduced the likelihood of aircraft loss when subjected to attack by ballistic threats. Study on rotorcraft survivability showed that the combat hostile action loss rate for aircraft in Operation ENDURING FREEDOM and Operation IRAQI FREEDOM was eight times lower than Vietnam, primarily because aircraft vulnerability reduction design reduced the cheap kills caused by the small arms and automatic weapon threats.9 O ccupantCCUPANT casualt CASUALT Y M & sS by John Manion and Philip RadlowskiThe goal of the Joint Aircraft Survivability Program sponsored Crew and Passenger Survivability Assessment project (M-08-09) was to develop a methodology to assess the survivability of aircraft personnel against hostile threats in the context of aircraft survivability. The project had joint involvement from the Army, Navy, and Air Force. Under the M-08-09 project, the Air Force and Navy each developed methodologies to assess occupant survivability using existing vulnerability analysis tools. As a risk reduction measure, it was decided that each of these methodologies would undergo proof-of-concept testing.14 S oldierOLDIER F irstI RST ..A N ewE W P aradigmA RADIGM in IN G roundR OUND V ehicleE HICLE D esignES IGN with WITH an AN E mphasisM PHASIS on ON S urvivabilitU RVIVABILIT Yby Chris WilliamsDesigners in the automotive commercial market have employed several methods of building vehicle safety around the occupant. Crumple zones are engineered to absorb the force of impact in collisions. Plastic interiors feature rounded edges to soften the blow after a crash. The industry incorporated knee bolsters and headliners so that drivers and passengers have a greater chance of walking away from a crash without serious injury. Historically, the US Army ground vehicles were not engineered with these consumer-focused methods.


h ttp:// AS A S Journal 13 / S S P R INI N GMailing list additions, deletions, changes, and calendar items may be directed to: SURVIAS URVIA C S S atellite Ofce 13200 Woodland Park Road Suite 6047 Herndon, VA 20171 Fax: 703/984-0756 Email: E Promotional Director Jerri L L i mer Creative Director Jerri L L i mer Art Director Michelle Meehan Technical Editor AA l exandra S S v em Journal Design DD o nald R R owe I llustrations, Cover Design, Layout II s mail R R a shada Karim R R a mzy DD u stin Hurt Distribution Statement A: Approved for public release; distribution unlimited, as submitted under OSD/DOT&E Public Release Authorization 13-S-1134. 17 PRACTICAL APPROACH TO AN INTEGRATED SURVIVABILIT YY ASSESSMENT by Torg Anderson and Sandra UgrinaIn November 2009, the Director, Operational Test and Evaluation issued a memorandum to his staff outlining his priorities. The Director stated, In time of war, getting capability to those in combat must be a priority. We will contribute by participating early in the development of all systemsboth rapid elding initiatives and major programsto provide insight on the operational and technical aspects of requirements, assure early testing discovers problems at a time when they can be xed most easily, and help develop the tactics, techniques, and procedures our forces need to make best, immediate use of new systems. 22 EX cellenceCELLENCE in IN S urvivabilitU RVIVABILIT Y D ennisE NNIS W illiamsI LLIAMS by Dale AtkinsonThe Joint Aircraft Survivability Program take great pleasure in recognizing Dennis Williams for Excellence in Survivability. Dennis has over 30 years of experience in the Operations Analysis Department at The Boeing Company, supporting aircraft survivability efforts. He has conducted survivability and vulnerability analyses to support Air Force Fighter competition proposals and progressed to managing the vulnerability engineering programs for the Advanced Tactical Fighter, F/A-18E/F, and EA-18G development programs.25 A ircrewIRCREW C ombatO MBAT S urvivabilitU RVIVABILIT Y and AND C ivilianIVI LIAN A ircraftI RCRAFT C abinA BIN S afetA FET Y : EX ploringP LORING and AND EX tendingT ENDING O ur UR C ommonOM MON G roundR OUND by Joel Williamsen and Isidore VenetosUS military aircraft are required to operate efciently in peacetime and effectively in wartime. Some of these requirements, including cabin safety, are common to both civilian airliners and military aircraft. Some attributes, including the combat survivability of aircraft and occupants to combat threats, are unique to military aircraft; however, many design attributes that improve cabin safety can also improve aircraft survivability.28 C rewREW C ompartmentOMPARTMENT F ireI RE S urvivabilitU RVIVABILIT Y T estingES TING by Patrick OConnell and Adam GossDue to the many combat incidents involving helicopters during the Afghanistan and Iraq conicts, the Director, Operational Test and Evaluation and the aircraft vulnerability community has increased their efforts to assess and improve aircrew survivability. Historically, during vulnerability testing of aircraft, little attention was given to assessing the crews survivability. The crew was primarily addressed during vulnerability modeling and given the same importance as any other critical component on the aircraft.


ASAS Journal 13 / SS P R INI N G h ttp:// 4 NN EWS No NO TESby Dennis Lindell SURVIVABILITYSURVIVABILITY P II O NEERN EER D D O NN MO WRERW RER P ASSES ASSES AWAY AWAY Donald W. Mowrer, a nationally recognized aircraft vulnerability analyst, consultant, and industry pioneer, passed away on 02 November 2012 after a brief illness. He was 87. Don will be remem bered as a quiet gentleman who always had time to help share his knowledge with others and who unselshly worked to help establish the eld of survivability as a formal engineering discipline. He was a charter member of the Joint Technical Coordinating Group on Aircraft Survivability (JTCG/AS), an early visionary for the Survivability/ Vulnerability Information Analysis Center as well as the Computation of Vulnerable Area Tool (COVART), and a leader of numerous aircraft survivability-related efforts for more than 50 years. Dons career began in 1951 as a mathematician at the US Army Ballistic Research Laboratory (BRL), where he helped determine aerial target vulnerability and weapon effectiveness. From 1961 to 1973, he worked as an aerospace engineer and expert in the structural characteristics and vulnerability of US and foreign aircraft and missile systems. Through 1981, Don worked as a physical scientist and manager of numerous survivability efforts and teams, serving as chairman of the JTCG/AS Vulnerability Assessment Subgroup, chairman of the Joint Technical Coordinating Group for Munitions Effectiveness Aerial Target Vulnerability Group, chief of the Aerial Targets Branch of BRLs Vulnerability/ Lethality Division, and chairman of the international committee for the lethality testing and survivability analysis of the ROLAND missile warhead. He also authored and led the publication of a 12-volume vulnerability assessment methodology report series. Following Dons retirement from government service in 1981, he served as a consultant to Armament Systems Inc., where he assisted in assembling and verifying computer kill probability input data for xedand rotary-wing analyses, updating lethal kill criteria, and outlining a procedure for developing a database of Pk/h values for aircraft engines. Don then joined his long-time friend and colleague, Jim Foulk, at the SURVICE Engineering Company, where he worked as an employee, vice president, and then consultant, focusing his efforts on data review, organization, and analysis; damage assessment; vulnerability reduction; and methodology development and application. In addition, Don spent much time mentoring young vulnerability and survivability analysts. In recognition of Dons half century of contributions in the eld, the National Defense Industrial Association honored him with its Lifetime Achievement Award in Combat Survivability in 1997. Although Don will be greatly missed by many in the community, his pioneering legacy will live on in the many air systems he helped to improve, many aviators he helped to protect, and many friends and colleagues whose lives he touched. AmAM ERI cC AN I I N STITUTE of OF AA E R o O NAUTI cC S AND AA S TR o O NAUTI cC S ( AIAAA IAA ) S S U RVIVABILITY TT E ch CH N I cC A L C ommO MM I TTEE ( SURT SURT C ) The AIAA promotes the development of survivability as a design discipline for both air and space systems through its SURTC. The SURTC is a diverse working group of professional members from academia, industry, and government who represent the aircraft and spacecraft communities. Committee members include distinguished experts and published authors, such as Professor Robert E. Ball, who authored The Fundamentals of Aircraft Combat Survivability and Design. In addition, many SURTC members provide subject matter expertise in diverse applications of the survivability discipline. The SURTC supports academic competi tions for aircraft survivability design, publications in the AIAA Aerospace America magazine, development of


5 h ttp:// AS AS Journal 13 / S S P R INI N Gspecications and handbooks, and the publication of position letters on topics of interest to the survivability community. The SURTC is also responsible for the organization of the survivability sessions at AIAA conferences. The SURTC formally meets twice a year and holds working teleconferences as well. Y Y o u can obtain more information on the technical committee by visiting tac/adsg/SURTC/. The SURTC held its most recent biyearly meeting during the evening of 23 October 2012 in conjunction with the National Defense Industrial Association Aircraft Survivability Symposium. The AIAA SURTC brings together experts in survivability from the civilian and military aerospace communities to „ H elp develop and administer the survivability sessions during the yearly Structures, Structural Dynamics and Materials Conference (SDM), including the recruitment and review of conference papers „ A dminister and review nominations for the prestigious biennial AIAA Survivability Award „ C onduct professional development courses, produce books, and serve as journal and book reviewers „ F ormulate technology assessment packages, standards, and other technical products „ D evelop and judge college student design competitions In the Spring of 2013, the AIAA will host its 54th SDM at the Boston Park Plaza Hotel and Towers in Boston, MA from 08 11 April 2013. The theme of the conference will be Materials Genome to Flightworthy Innovative Structures. The SURTC will have one survivability session during this conference. Scientists and engineers involved in aircraft survivability are encouraged to attend this conference. Subsequently, the SURTC will participate in the 2014 AIAA Science and Technology Forum. Watch the AIAA website ( for up-to-date information. The SURTC is actively recruiting members with survivability expertise, particularly in the areas of crew and occupant survivability; susceptibility and vulnerabil ity analysis; and reduction technologies. Members with expertise in rotorcraft and spacecraft survivability are needed, as well as those from the naval aviation and space communities. AIAA committees are the workhorses of the institute, and participation offers incredible opportuni ties for networking, resume building, and professional development. All SURTC members must be AIAA members. If you are interested in participating in the SURTC, please contact the SURTC chair elect. C oO NS o O RTIU mM fo FO R AA I R cC R A fF T S S U RVIVABILITY EE NVIR oO N m M EN TThe Project Management Ofce Aircraft Survivability Equipment (ASE), Program Executive Ofce Intelligence, Electronic Warfare and Sensors is in the process of researching the benets of a consortium. The dynamics of the threat environment coupled with acquisition challenges require a different way to conduct business to provide our soldiers the best integrated and affordable protection. The consortium research effort is led by, the University of Alabama in Huntsville, Rotorcraft Systems Engineering and Simulation Center. A consortium would provide a collaborative environment to bring government, industry, and aca demic stakeholders together to enable the aircraft survivability vision of the future. More information to follow in future issues. JC ATAT C oO RNERby CAPT Bill Little, USN and LTC Chuck Larson, USAF The Joint Combat Assessment Team (JCAT) continued its deployment to Operation ENDURING FREEDOM (OEF) in support of Combined Forces Aviation. During F YY 1 2, JCAT forward-deployed ve United States Navy (USN) and seven United States Air Force (USAF) personnel to Afghanistan to serve with the Coalition Air Component Commanders supporting OEF counter-insurgency operations. This commitment totaled 940 man-days of Contiguous United States (CONUS) support and 1,669 man-days of outside Contiguous United States support. The Army Component executed three no-notice deployments in support of four catastrophic loss events for a total of 125 man-days. Deployed JCAT personnel experienced an extremely busy summer and early fall as Afghanistans traditional ghting season ran its course. F YY 1 2 saw the JCAT conduct 223 enemy threat assessments, a 32% increase compared to 162 in F YY 1 1; this is also the new all-time record for thecontinued on page 23


ASAS Journal 13 / SS P R INI N G h ttp:// 6 CASUALTY AA S SESS mM ENT AND R R E DU c C T I o O N AA T T hH E 5 YY E AR MAR kK C OO V EE R STO STO R YY by RR ick S S ayre


7 h ttp:// AS AS Journal 13 / S S P R INI N GThe human fatality rate associated with combat hostile action losses also showed a reduction from Vietnam to OEF/OIF, but not to the same extent. Some of this decrease in the fatality rates can be attributed to having more survivable aircraft, but improvements in airframe crashworthiness and crash protection for passengers are necessary to further reduce fatalities and injuries. Table 1 displays the Department of Defense (DoD) rotorcraft fatalities from October 2001 through August 2012 (OEF/ OIF time frame). There were four types of fatalities seen in the combat data: those that were a result of threat effects directly hitting the person; those that were a result of a catastrophic crash; and those that were a result of a survivable crash, and those where the cause of the fatality is attributed to both threat impacts and crash effects (a catastrophic crash occurs when no crewmembers or passengers survived after the aircraft crash, and a survivable crash occurs when at least one crewmember or passenger survived after the aircraft crash). We should continue to focus on technolo gies that reduce fatalities when the threat or threat effects directly hit pilots, aircrew, or passengers; however, data shows that 207 fatalities come from survivable crashes. Clearly more effort is needed in improving crashworthiness, which is a common area of interest between the safety and live fire test and evaluation (LFT&E) communities, and both communities should work together to reduce casualties. Additionally, one of the primary ways to reduce fatalities from catastrophic crashes from combat incidents is to prevent the event from occurring by reducing the susceptibility or vulnerability of the aircraft. Fatalities from survivable crashes can also be reduced by preventing the crash from occurring, but they can also be reduced through a combination of improvements in crashworthiness and egress. Five years ago, guidance was issued to JASP to broaden their scope and refocus their efforts, and to work in concert with the aircraft safety community to predict and reduce combat-related occupant (passenger and crew) casualties. In support of this effort, JASP was directed to „ C onduct background investigations into the causes and types of occupant casualties, using combat and safety-related incident data „ A ssess potential for occupant casualties in joint LFT&E, which may include specialized crash and/or egress-related testing „ D evelop/expand tools that predict probability/number of casualties, crash conditions at landing, and crash effects on occupant, including failed egress „ I dentify and evaluate new casualty reduction features for aircraft considering crashes, hard landings, and ditching at sea „ C oordinate with other organizations within and outside the DoD ( e.g., Acquisition Technology and Logistics, Safety Centers, Department of Homeland Security, Federal Aviation Administration [FAA], National Aeronautics and Space Administration [NASA]) to accomplish these goals JASP has pursued many of these efforts that improve casualty assessment and reduce casualties, each with some degree of success. The Joint Combat Assessment Team has expanded its mission to examine and record the causes of combat casualties in existing combat theaters. Joint live fire testing to determine the extent of casualties that are associated with cabin-induced fires in large transport helicopters, including Since Vietnam, the Joint Aircraft Survivability Program (JASP) has supported the development of critical technology that signicantly reduced the likelihood of aircraft loss when subjected to attack by ballistic threats. The 2009 study on rotorcraft survivability showed that the combat hostile action loss rate for aircraft in Operation ENDURING FREEDOM (OEF) and Operation IRAQI FREEDOM (OIF) was eight times lower than Vietnam, primarily because aircraft vulnerability reduction design reduced the cheap kills caused by the small arms and automatic weapon threats. [1] Cause of Fatality Combat Hostile A A c tion MishapsPilot Pax/ Crew UU n known TT o tal Pilot Pax/ Crew TT o tal Threat Directly Hitting Person 23 45 0 68 Catastrophic Crash 26 58 0 84 108 137 245 Survivable Crash 10 14 5 29 66 117 183 Both Threat and Crash2 15 0 17 TT o tal 61 132 5 198 174 254 428 TT a ble 1 DoD Rotorcraft Fatality Data (October 2001 to August 2012)


ASAS Journal 13 / SS P R INI N G h ttp:// 8 heat, toxic smoke, and oxygen depletion. This effort may lead to new technologies or operational protocols to reduce fires or improve occupant survivability until a safe egress after landing. Two casualty prediction methodologies have been developed based on existing Computation of Vulnerable Area Tool (COVART) and Modular Unix-Based Vulnerability Estimation Suite (MUVES) models to support aircraft vulnerability evaluation programs. One of the methodologies is being utilized in part to support passen ger casualty evaluations for the K K C -46 following ballistic impact. Improved crew armor, cabin fire reduction, and crashwor thy seat technologies have been pursued and show promise for further reducing casualties. And finally, JASP is working with NASA and the FAA to test and integrate aircraft safety features that might reduce aircraft casualties following ballistic attacks. Despite the JASP advances made towards establishing a framework for casualty assessment, several important model and test capability gaps exist that limit the direct application of these techniques for reducing casualties. The two highest priorities for development include determining the changes to flight performance and controllability of the aircraft following ballistic damage that can be used in flight simulations and models to provide potential ground impact conditions, and examining indirect effects (smoke, fire, toxic gases, etc. ) to quantify the impact on casualties during continued flight operations and occupant egress after landing. Other important efforts that JASP and the live fire community must support include the following: „ A c loser examination of the cause of casualties in military aircraft (and civil aircraft platforms of similar construc tion) using combat and safety-related incident data. It is important that relevant medical data be collected and reviewed to focus on areas that cause the greatest number of injuries and fatalities. Joint programs planned with the FAA hold signicant promise for this, but a more in-depth evalua tion of military aircraft safety and combat data is warranted. „ D evelopment of a set of guidelines outlining the casualty assessment methodology that will standardize practices used to assess aircraft occupant survivability. These guidelines should include: denitions, terminology, metrics, objectives, assumptions, limitations, ground rules, standard vignettes, best practices, and data needs that could lead to required testing. A similar set of guidelines is currently under development within the Director, Operational Test and Evaluation for evaluating ground vehicle casualties, and some commonality should be seen between the ground vehicle and aircraft communities. From these guidelines, appropriate testing requirements should be developed that will be included in future test and evaluation master plans. „ E stablishment of baseline occupant survivability assessments for the current eet of rotorcraft and transport aircraft. If new technologies are to be incorporated, they must show that they reduce fatalities and injuries. The Armys new Full Spectrum Crashworthiness Criteria for Rotorcraft [2] provides an excellent starting point for establish ing baselines for rotorcraft, and similar criteria should be developed (with assistance from the FAA) for transport aircraft. Although ejection seats on tactical jet aircraft eliminate many of the concerns for crashworthiness, baseline crew survivability assessments should still be established. Acquisition decision makers, system designers, and requirements writers need quantifiable casualty predictions to evaluate applicable technologies and procedures that reduce occupant casualty risk after initial aircraft hits. Although aircraft survivability evaluation method ologies have historically focused on what happens to the aircraft in a combat event (with only a limited consideration of personnel casualties resulting from combat-induced aircraft losses), JASP has demonstrated that these methodolo gies can be modified to include the prediction of casualties to the point of egress prior to or following a hard crash or safe landing. The assessment of aircraft occupant casualties to the point of safe return or egress continues to be an important element of LFT&E, including the evaluation of personnel casualties due to combat-related, in-flight escape and crash events. JASPs portfolio of efforts to reduce the onset of aircraft losses through vulnerability reduction, susceptibility reduction, and survivability modeling will be enhanced by these new efforts to reduce occupant casualties. Reducing casualties is and continues to be of paramount importance to the DoD, not only for aircraft, but for ground vehicles and ships as well. This crossplatform emphasis on casualty reduction technologies will identify common areas of research applicable to aircraft, ground vehicles, and ships. continued on page 13


9 h ttp:// AS AS Journal 13 / S S P R INI N GC oO NDITI oO NAL PR o O B ABILITY MET hoHO D o O L oO GYThe Conditional Probability methodology was developed to assess crew and passenger casualties while leveraging existing aircraft vulnerability tools and methodologies. Signicant effort and resources have already been spent evaluating aircraft vulnerability, which is a key factor in assessing personnel survivability and casualties. The rst part of the methodology captures the effects of direct threat impacts on the aircraft and personnel. The purpose is to quantify the end state of the aircraft. This is accomplished using the probability of kill (Pk) for each time-based kill level modeled, and using a Weibull distribution to account for the time in between kill levels. This methodology requires the analyst to make correlations between the kill levels and the corresponding end state(s) of the aircraft (Figure 1). These correlations are based on multiple factors including the aircraft type, mission, and operating environment. The impacts of the threat on all the aircraft systems and personnel are also captured. Certain aircraft systems can result in secondary effects in personnel areas such as re, smoke/toxic fumes, etc. and may result in personnel casualties. The second part of the methodology quanties the probability of casualty (Pc) for each person based upon the end state(s) and resulting egress type(s) corresponding to the end state. For example, an aircraft that is predicted to fall out of manned control in less than 30 minutes may attempt a hard landing, order an air egress of all personnel, or be able to land at the base. Multiple factors contribute to the determination of casualties for each end state and egress type. O ccCC U pP ANT cC A SUALTY M&Sby John Manion and Philip Radlowski The goal of the Joint Aircraft Survivability Program (JASP) sponsored Crew and Passenger Survivability (CAPS) Assessment project (M-08-09) was to develop a methodology to assess the survivability of aircraft personnel against hostile threats in the context of aircraft survivability. The project had joint involvement from the Army, Navy, and Air Force. Under the M-08-09 project, the Air Force and Navy each developed methodologies to assess occupant survivability using existing vulnerability analysis tools. As a risk reduction measure, it was decided that each of these methodologies would undergo proof-of-concept testing. The Air Force and Navy successfully conducted proof of concept (PoC) analyses using their respective methodologies. This article summarizes those methodologies and potential challenges that lie ahead. For purposes of this article, the Air Force-developed methodology is referred to as the Conditional Probability methodology and the Navy-developed-methodology is referred to as the Integrated CAPS methodology. O ccCC U pP ANT cC A SUALTY M&S A-Kill Pk = 0.22 K-Kill Pk = 0.05 Weibull Curve Fit B-Kill Pk = 0.56 Pair_egress + Pcrash_landing_egress= 1.0 (PRTB_egress + Pno_egress) Pno_egress = A-Kill PRTB_egressbased on CDF 5 minute loss of control (A-Kill) implies no egress possible CAPS analyst enters estimated time of flight to RTB (may or may not consider degraded flight performance). This input will influence CAPS result and may be part of trade study Time (min) P(Out of Manned Control) 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 60 120 180 240 Figure 1 Aircraft End State


ASAS Journal 13 / SS P R INI N G h ttp:// 10 The result of the methodology is a Pc for each person on the aircraft. These Pc values can be reported to support multiple different metrics. For example, the Pc of one or all personnel or the Pc for a particular person could be reported. The conditional probability methodology has not yet been integrated into the vulnerability codes. As a result, the calculation of other metrics ( e.g., Pc of 10 and only 10 personnel) is tedious, but possible. A PoC analysis was conducted using the Conditional Probability methodology. The methodology was executed with the Fast Shotline Generator and the Computation of Vulnerable Area Tool vulnerability codes. A transport aircraft was used as the test bed for the analysis to model predicted casualties of passengers. The aircraft and personnel were assessed against a high explosive round. The explosive nature of the threat exercised multiple damage mechanisms for a more robust testing of the methodology. Multiple changes were made to the aircraft model to test the various attributes of the Conditional Probability methodology. Twenty persons were added to the main cargo area. Two components with potential secondary effects were modeled. There was a number two engine (uncontained engine debris) and a hydraulic reservoir (re) in the main cargo area. The secondary effects components allowed for the analysis to assess the impact on personnel in addition to the effect on the aircraft. Not all potential secondary effects components were modeled for the PoC analysis. The PoC analysis involved signicant amounts of estimated data to populate the various casualty contributing factors. Potential sources for this data are available and were identied in the Aircraft Combat Occupant Casulaty Assessment State of the Art Report (JASPO-M-08-09002). Other factors such as the impact conditions and resulting loads on the personnel are more difcult to determine. The PoC analysis demonstrated that the Conditional Probability methodology could be successfully executed. Sensitivity studies were conducted to better understand the parameters that most affected the results. In the process of conducting the analysis, methodology bugs were identied and the lessons learned were documented in the PoC report (JASPO-M-08-09-004). Because of the input data estimates, the results cannot be considered authoritative; future crew casualty analyses will need to better quantify the casualties due to ground impact along with other contribu tors outside of the typical aircraft vulnerability analysis. Provided the input data is developed, the Conditional Probability methodology is capable of serving as the basis for aircraft personnel casualty analyses. The methodology and PoC analysis provide a framework where future analyses can be conducted. The Conditional Probability methodology also has the ability to easily expand to accommodate additional casualty contributing factors that may be the result of different aircraft, different operating conditions, or from an increased knowledge base of these factors. II NTEGRATED C AA P SS MET hoHO D o O L oO GYThe goal of the Integrated CAPS methodology was to develop a process that includes occupant casualty as a vulnerability design consideration, can be performed within the aircraft acquisition process, and uses existing vulnerability data and tools as much as possible. The Integrated CAPS methodology achieves this goal by building from the existing vulnerability analysis process and data. It uses the same methods, tools, and input types as the current vulnerability assessment process. The key to the Integrated CAPS methodology is the fault tree. The fault tree for the Integrated CAPS methodology builds from existing vulnerability data, but changes the focus from the aircraft to the occupant. Each occupant is treated as a system whose state depends on the damage types listed in Table 1. The top level of the Integrated CAPS methodology fault tree focuses on the aircraft damage types (Aircraft Damage in Table 1). These damage types affect the occupants in different ways. For example, one damage type considered in the PoC testing was catastrophic aircraft damage. This damage will affect all occupants globally in that no one occupant will survive. Other aircraft damage types, such as damage that results in specic crash conditions, may affect each occupant differently. In these cases, the fault tree must be expanded to include the effects of the threat and crash conditions on each occupant and must also consider all of the damage types listed in Table 1. The resulting fault tree is highly complex. Figure 2 shows an excerpt of the resulting fault tree on a notional aircraft with ve levels of aircraft damage identied. In Figure 2, the top level of the fault tree is the probability of N or more casualties. There is one fault tree constructed for each N (N=1,2,3; total number of occupants). These probabilities are then combined to into one top-level metric called Expected Number of Casualties.


11 h ttp:// AS AS Journal 13 / S S P R INI N G Probability of at least M casualties PNCas PCasCAT PCAT PCR1 PCR2 PCasgCR2 PCasgCR2.fta MofN PFL PCasFL PRTB PCasRTB PCas/CR1 PPilCasCR2 PPilotCasCR2 PPilCasCR2CWD PCasCR2CWCrew PCasCR2EgCrew PCasCR2Eg Crew PEDCR2 PITE1 .fta PPilCas/ITE1 PDamEgress Pdamcw PPilCasCR2ED PPilCasCR2ED PPilotCasITE1 PPilotCasITE2 PCasCR2NENCW PPilotCasDTE PPilotCasITE PCPCasCR2 PO1CasCR2 PO2CasCR2 PONCasCR2 PCAS/CAT PCasCR PCasCR PCasFL PCasRTB Probability of at least M casualties due to Crash 2 level damage event Probability of at least M casualties due to forced landing event Probability of at least M casualties due to Return to Base damage event Probability of at least M casualties due to Crash 1 level damage event Probability of Pilot Casualty due to crash-2 damage Probability of Pilot becoming a casualty due to crash-2 conditions Probability of Casualty given crash-2 conditions and damage to crashworthy systems Probability of threat damage to crashworthy systems Probability of casualty given crash-2 conditions and damage to egress systems Probability of threat damage to egress systems Probability of casualty associated with egress system damage caused by Crash-2 conditions Probability of Pilot Casualty due to indirect threat effect 1 Probability of Indirect Threat 1 occuring Probability of Pilot Casualty due to indirect threat effect 2 Probability of Pilot becoming a casualty due to direct threat effects Probability of Pilot Casualty due to indirect threat effects Probability of Copilot Casualty due to crash-2 damage Probability of Occupant 1 Casualty due to crash-2 damage Probability of Occupant 2 Casualty due to crash-2 damage Probability of Occupant N Casualty due to crash-2 damage Probability of at least M casualties due to catastrophic aircraft damage event Probability of Catastrophic DamageDetailed Aircraft System Fault Tree Detailed Aircraft System Fault Tree Detailed Aircraft System Fault Tree Detailed Aircraft System Fault Tree Detailed Aircraft System Fault Tree Detailed Casualty Fault Trees Pilot Casualty Fault Tree Copilot Casualty Fault Tree Direct Threat Effect Fault Tree Indirect Threat Effect 2 Fault Tree Indirect Component Fault Tree Egress System Fault Tree Crashworthy System Fault Tree Occupant 1 Casualty Fault Tree Occupant 2 Casualty Fault Tree Occupant N Casualty Fault Tree Detailed Casualty Fault Trees Detailed Casualty Fault Trees1.0 1.0 1.0 1.00.1 f(r) = Conditional Probability 1.0 0.0Probability of Crash-1 Damage Probability of Crash-2 Damage Probability of Casualty given Crash-2 Damage Probability of Forced Landing Damage Probability of RTB Damage Probability of Casualty given Forced Landing Damage Probability of Casualty given RTBV DamageCasualty Fault Tree with Conditional Probabilities (Partially Expanded) Probability of N or more casualties Figure 2 Excerpt of Fault Tree TT a ble 1 Damage Types for Passenger-centric Fault Tree AA ircraft D D amage The threat damages ight critical components resulting in degraded perfor mance and possible crash. The conditions of the crash can cause occupant injury. Multiple levels of damage need to be dened to determine occupant casualty state. DD i rect T T hr eat D D a mage The threat injures occupant directly via threat damage mechanisms ( e.g., penetration, blast, heat). II n direct T T hr eat D D a mage The threat damages component near occupant, causing a reaction that releases secondary mechanisms and injures the occupant ( e.g., re, smoke, hot uid, overpressure, blunt force). TT h reatII nduce d Crashworthy S S y stem DD amage The threat damages crashworthy systems associated with the occupant, disabling its protection capability. Upon a crash landing, the occupant is more likely to become a casualty. TT h reatII nduce d E E gr ess SS y stem D D amage The threat damages the egress components associated with the occupant, hindering or preventing proper egress. CrashII nduce d E E gr ess SS y stem D D amage The crash conditions cause damage to egress system components, hindering or preventing proper egress. TT h reatII nduce d E E gr ess Hindrances The threat damages aircraft components that hinder/prevent proper egress ( e.g., re, smoke, obstructions). CrashII nduce d E E gr ess Hindrances The crash causes damage to aircraft components that hinder/prevent proper egress ( e.g., re, smoke, obstructions, crushing).The Expected Number of Casualties is a single number that, like the standard Vulnerable Area metric, relates the value to a specic threat condition ( e.g., man-portable air defense system missile impacting at a specic velocity). This single value supports design trade studies as illustrated in Figure 3. In addition to the Expected Number of Casualties, samples of other information attainable from the Integrated CAPS methodology are shown in Figure 4. The various outputs of the Integrated CAPS methodology allow for the determination of key areas to focus


ASAS Journal 13 / SS P R INI N G h ttp:// 12 vulnerability reduction designs. This was demonstrated in detail as part of the Navys PoC testing. [1] The Integrated CAPS methodology was implemented in the Advanced Joint Effectiveness Model (AJEM) vulnerability tool. AJEM was selected due to its highly exible and adaptable fault tree input and interrogation algorithms that were necessary to implement the Integrated CAPS methodology. The Integrated CAPS methodology examines all of the PN-or-More-Casualty fault trees for each threat interaction in AJEM. AJEM then rolls up the probabilities over all of the possible threat interactions and provides metrics to directly compute the Expected Number of Casualties. AJEM also directly provides all data shown in Figure 4. Expected Number of Casualties versus Aircraft Design Expected Number of CasualtiesAircraft Configuration Baseline 0 2 4 6 8 10 12 Design 1 Design 2 Design 3 CATASTROPHIC CRASHONE CRASHTWO FORCEDLAND RTB System N-or-more Casualties Number of Casualties 0 0.05 0.1 0.15 0.2 0.25 0.3 0 123456789 101112131415 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 123456789 101112131415 0.1 0.05 0.15 0.2 0.25 0.3 0.35 0.4 48% 33% 3% 8% 8% Aircraft Damage State Breakdown Pk Contributions by Aircraft System Probability of Exactly N Casualties Probability of N-or-more CasualtiesProbability ProbabilityStructure Propulsion Crew Flight Controls Fuel Drive Hydraulics Rotors Avionics Misc Catastrophic Crash-1 Crash-2 Figure 3 Illustration of Use of Expected Number of Casualties Figure 4 Examples of Outputs from Integrated CAPS Method


13 h ttp:// AS AS Journal 13 / S S P R INI N GPoC testing by the Naval Air Systems Command (NAVAIR) Combat Survivability Division was successful in demonstrating the Integrated CAPS methodologys capability to assess occupant survival probabilities and support design trade studies. Details of the methodology and testing results are documented in the JASP report titled Crew and Passenger Survivability (CAPS) Methodology and Proof-of-Concept Testing. [1] FUTURE DD IRE cC T I oO NSAlthough the PoC testing of the Conditional Probability and Integrated CAPS methodologies were completely successful, there are specic inputs identied from both methodologies that require further examination. Referring to Figure 2, the data in the green circles represent various conditional probabilities that had to be assumed during the Integrated CAPS PoC testing. Identical parameters were identied in the Conditional Probability methodology as well. Determining the actual values for these conditional probabilities will require signicant efforts in areas of expertise outside of the vulnerability discipline. At the initiation of M-08-09, a state-ofthe-art report was published (JASPO-M-08-09-002), which identies the potential organizations that can help in generating these conditional probabili ties. Following this PoC testing, the state-of-the-art report is being updated and a road map is being generated to develop methodologies that will produce valid values for these conditional probabilities. RR e ferences[1] Crew and Passenger Survivability (CAPS) Methodology and Proof-of-Concept Testing, JASPO-M-08-09-005, December 2011 (Classied CONFIDENTIAL).CASUALTY AA S SESS m M E NT AND R R E DU c C T I oO N AA T T hH E 5YY E AR MAR kK continued from page 8 RR eferences[1] Study on Rotorcraft Survivability Summary Report, Department of Defense, Washington, D.C., September 2009. [2] F ull Spectrum Crashworthiness Criteria for Rotorcraft, RDECOM TR 12-D-12, U.S. Army Research, Development & Engineering Command, Fort Eustis, Virginia, December 2011.


ASAS Journal 13 / SS P R INI N G h ttp:// 14 Historically, the US Army ground vehicles were not engineered with these con sumer-focused methods. Legacy vehicles featured the survivability onion concept, which took an outside-in approach to vehicle safety, following the philosophy of dont be seen; if seen, dont be acquired; if acquired, dont be hit; if hit, dont be penetrated; if pen etrated, dont be killed. That philosophy worked well when vehicles were designed primarily for force-on-force frontal attacks. In this new era of persistent conict and close-in asymmetric threats, that mentality is no longer valid. Improvised explosive devices (IEDs) have changed the picture. IEDs not only have the potential to destroy vehicles, but blasts below the hull often throw soldiers inside the vehicle, where sharp edges, exposed wires, loose objects (pry bars, ammo, etc.), and hard steel can cause serious secondary injuries or death. The Army has determined that quick-response solutions help, such as increased armor, different belly plates, or new hull designs, but they are not optimal. Instead, vehicle design must be rethought, from the inside-out, with the focus on keeping soldiers alive and safe. RR ET hH IN kK ING SS U RVIVABILITYThe Armys Force Protection Occupant Centric Platform (OCP) Technology Enabled Capability Demonstration (TECD), led by the US Army Tank Automotive Research, Development, and Engineering Center (TARDEC), began in F YY 1 2 and is scheduled to continue through F YY 1 5. The OCP TECD will set the Army standard in creating vehicles, and it includes the following: „ I ncreased protection from current and emerging threats „ O ptimized interior space for soldiers and gear „ D ecreased technology weight „ M aintained maneuverability „ F ull-spectrum operational design The OCP TECD gave engineers the opportunity to re-examine ground vehicle design with a greater emphasis on occupant protection, leading them to step back and ask vital questions: How should vehicle interiors be designed? What materials should the armor contain? What exactly happens during an IED blast and how do vehicle occupants respond? How well do various technologies protect soldiers from injury and death? How do we take all this knowledge and integrate these new technologies without sacricing size, weight, power, and cooling in a system? SS ETTING SS TANDARDS WIT hH A C AA M ELE L Of the deliverables dened by the end of the OCP TECD, the most important will be the creation of an overarching military standardincluding design guidelines, technical specications, and test operations proceduresthat is titled SoSO LDIER FIRST... AA N N EW PARADIG m M I N G G R oO U ND VV E hH I cC L E D D E SIGN WIT hH AN EmphE MPH A SIS o O N S S UR VIVABILITYby Chris WilliamsDesigners in the automotive commercial market have employed several methods of building vehicle safety around the occupant. Crumple zones are engineered to absorb the force of impact in collisions. Plastic interiors feature rounded edges to soften the blow after a crash. The industry incorporated knee bolsters and headliners so that drivers and passengers have a greater chance of walking away from a crash without serious injury.


15 h ttp:// AS AS Journal 13 / S S P R INI N GOccupant Centric Survivability for Military Ground Vehicle Design. We have to design a standard for the Army, explained Steve K K n ott, Associate Director for TARDEC Ground Systems Survivability (GSS). Its not just adding to the vehicle; its designing from the ground up, starting with the occupant. We will manage the standard for the rest of its life with our customers at the project management ofces, private industry, and the test and research community. It will be a living, breathing document that exists and is maintained across the community. The OCP TECDs second deliverable, Occupant Centric Survivability Demonstrator, will be the physical representation of the design guidelines and specications created through this program. K K n own as a CAMEL, the platform will be a crew compartment designed for maximum occupant survivability. Whys it called a CAMEL? Because I dont want people to think about it being a tracked or wheeled vehicle, K K n ott explained. It is going to be the physical representation of what right looks like. To that end, TARDECs GSS Team is looking at 29 different areas to determine which seats, occupant congurations, materials, and interior designs will best protect soldiers. Features such as seating, restraints, hull shape, and storage will be examined to determine how to best integrate these features into the system to offer maximum protection. All of these technologies are being worked up front, remarked K K n ott. Right now were still early in the process. December 2012 is when were scheduled for Preliminary Design Review, when we expect to see a preliminary glimpse at whats in and whats out. I can tell you there are going to be seats, but what does the seat need to do? Those are the things that were working through. The CAMEL will be a prototype demon strator, not designed for production, but to show what optimal protection looks like. The TECDs third and fourth deliver ables will take the CAMELs concepts and how to apply them to platforms for lightweight and heavyweight vehicles to show how they may impact current and future systems. Were picking the Mine-Resistant Ambush-Protected All-Terrain Vehicle as a light platform and the Bradley as the heavy class platform to take what weve learned and deter mine the impact on current systems, KK n ott explained. The programs focus is to get the standards in place to set the Army up for the future. M oO DELING So SO LUTI oO NSAdvanced computing systems have been valuable tools as GSS engineers develop these new standards. In the past, engineers took a trial-and-error approach, using expensive prototypes and lengthy experimentation to discover which technologies and methodologies worked best. Recently, Heidi Shyu, Acting Assistant Secretary of the Army (Acquisitions, Logistics and Technology) and Army Acquisition Executive, emphasized that using modeling and simulation (M&S) to solve development issues will benet the Army. As our budget realities present funding constraints, there is a real need for processes that save both time and money in expediting the elding of needed equipment, Shyu stated. Increased reliance on high-delity modeling and simulation technology can shorten development schedules by eliminating unnecessary testing and reduce sustain ment costs by enabling realistic training for soldiers responsible for maintaining weapon systems. These and other lessons from the past decade of combat are integral to our future equipping efforts, regardless of the threat. [1] Today, TARDECs advanced M&S capabilities allow hundreds of virtual experiments to run in a short amount of time before a single piece of metal is bent to fabricate a prototype. Over the past decade, this capability has been advanced and rened to provide an in-depth, accurate, and indispensable tool to better understand how soldiers and vehicles react during blasts, crashes, and rollovers. Seven or 8 years ago, we had very basic models and computational tools to address blast issues. Now we have full-edged suites of computational tools to address not only occupant injury risk assessments, but also structural performance at a system level, remarked Sudhakar Arepally, Deputy Associate Director for TARDECs Concepts, Analysis, Systems Simulation, and Integration Analytics Team. We have a top-of-the-line, advanced computational and high performance computing environment. We are able to deliver computational results to the customer much faster. What would once take months, we are now able to deliver in a Figure 1 Five Point Harness Seat


ASAS Journal 13 / SS P R INI N G h ttp:// 16 few weeks based on advanced modeling techniques, experienced staff, and upgraded computing platform. A better approach to occupant survivabil ity begins with a better understanding of vehicle occupants themselves. Models previously depicted soldiers as one body type and build, and did not account for how the increased gear that soldiers carry impact their posture, which greatly contributes to injury. By examining various types and sizes of soldiers in a variety of postures and seating congura tions, TARDECs M&S experts can better understand how occupants react in emergencies. Once the impact at the underbelly occurs and the shockwave propagates through the vehicle, you have turbulence inside the occupant compartment, where different body regions experience different impact scenarios, explained Arepally. We collaborate with the RDECOM [Research Development and Engineering Command] and the Army Research Laboratory to leverage their science and technology capabilities, and OEMs [other equipment manufacturers]/ suppliers to harness their product knowledge, data, and models. Advanced computational M&S has also led to a greater understanding of how blast events occur and how they affect the vehicle. During IED blasts, a complex series of events occur in the blink of an eye, and everything from charge depth, soil compaction, armor materials, and hull shape can impact the way vehicles and occupants react. TARDECs M&S tools allow engineers to be better prepared to conduct experiments with hull shapes, blast variables, and occupant orientation to understand what happens in a blast event, how it affects vehicles and occupants, and what solutions may yield the best results. We are looking at the system levelthe entire vehicle, including tires, chassis, powertrain, seating, seatbelts, and airbags. In one computational run, we are able to look at the entire system-level performance; its a big step from where we were, Arepally commented. But our models still dont take into account the variability and uncertainty involved in this complex phenomenon. The way the soil is placed, for instance, depends on the soils compaction, moisture content, and granularity. That all must be perfectly aligned, because even if it deviates a little bit, the end result will be affected, Arepally continued. What we are trying to understand at this point is how much it will be changed or affected by the soil parameters. And the entire blast-kill chain comprises of different things [such as] soil, material properties, and manufacturing variability. As a result, the challenge that we persistently face is to improve predictive capability of the models. These capabilities will help GSS engi neers understand how to best design vehicles to prepare for blast events. YY o ur car is designed to put you in a position, remarked K K n ott. A lot of people dont understand the engineering involved in a car to help position the occupant appropriately to ride the crash down. Things like side-cushion airbags or airbags that come out of the door to put the person in position to ride the crash. The models allow us to get a rough order of magnitude of potential technolo gies. It helps us whittle down to a right answer, commented K K n ott. Its not the answer, but it helps us know were in the right ballpark. M&S tells me what stadium Im in, but then I have 30,000 seats inside where I can sit. The information gleaned from computa tional analysis will help GSS as it develops the Armys occupant-centric survivability standard. At the end of the program, the Army will have standards in place to properly design vehicles that allow all crewmembers to safely complete missions. In addition to the Army standards and the three demon strator vehicles, the greatest deliverable of all will be seen in the soldiers who return home safely because of the work done by the Amys engineers and their partners. The technology thrust areas for the Occupant Centric Survivability Demonstrator include the following: „ H ull shaping and materials „ A bsorption materials „ Re duction of hard points „ S towage „ A ir bags „ I nnovative ergonomics ingress/egress „ E ffective seating „ F ire suppression systems „ R estraints „ V ehicle sensing and electronics „ M obility systems/active safety RR eferences[1] Shyu, Heidi. Army Equipment Modernization: Preparing to Deliver Future Decisive Capabilities. ARM YY Magazine. October 2012. Volume 62, Number 10. archive/2012/10/Documents/Shyu_1012.pdf .


17 h ttp:// AS AS Journal 13 / S S P R INI N GTo enforce this priority, the Director laid out four initiatives: (1) eld new capability rapidly, (2) engage early to improve requirements, (3) integrate developmen tal, live re, and operational testing, and (4) substantially improve suitability before initial operational test and evaluation (IOT&E). The third initiative is directly applicable to an Integrated Survivability Assessment (ISA) because such an approach depends on data from developmental, live re and operational testing. Early engagement and planning inherent to a successful ISA also helps to ensure an improved and more efcient assessment, expediting the overall elding process. LL I mM ITATI oO NS T oO P REVI oO U S ISA ISA C oO N cC E pP T SAn ISA approach has been of interest to DOT&E since the early 1990s. Several reports published in the last 20 years have dealt with the methodology of an ISA. These studies provided thoroughly dened ISA approaches that focused on solving all elements of the kill chain equation for each chosen mission scenario. The Joint Aircraft Survivability Program (JASP) even developed a generic checklist and a hierarchy of metrics for such calculations. They determined how the metrics would be evaluated using existing models and simulations (M&S) and test ranges; however, given the magnitude of recognized M&S decien cies and uncertainties in assessing each element in the kill chain some research ers have concluded that signicant resources are required to mature and fully implement the ISA process. DOT&E did not adopt any of these approaches as a standard practice. Meanwhile, understanding what constitutes an integrated assessment has varied within the survivability community. Approaches implemented in earlier acquisition programs have often been limited to merely assembling otherwise independently collected developmental, live re, and operational test ndings into one document. For various reasons, including conicts in the acquisition schedule, such approaches have not been efcient, did not uniformly consider all relevant conditions or ndings, and resulted in last-minute issues whose resolution had become impractical and costly. More importantly, such federated ndings could not easily be interpreted in a context that would be valuable to decision makers and operators. Successful implementation of an ISA concept has been limited by several more general issues. Issue 1: Survivability is highly dependent on the operational context. While the common meaning of survivabil ity is a simple and clear ability to stay alive, assessing survivability of a Department of Defense (DoD) acquisition product is not a straightforward task. System survivability cannot be assessed without rst identifying the operational context in which the system is used, including the types, capabilities, and probable distributions of expected threats. Because system survivability is dependent on those multiple factors, it will vary, sometimes signicantly, as operational and engagement scenarios AA P RARA C TITI C ALAL A A PP RR O AA C H TT O AN AN INTEGRATED INTEGRATED SURVIVABILITYS URVIVABILITY ASSESS ASSESS M ENT ENT by Torg Anderson and Sandra UgrinaIn November 2009, the Director, Operational Test and Evaluation, (DOT&E) issued a memorandum to his staff stating that In time of war, getting capability to those in combat must be a priority. We will contribute by participating early in the development of all systemsboth rapid elding initiatives and major programsto provide insight on the operational and technical aspects of requirements, assure early testing discovers problems at a time when they can be xed most easily, and help develop the tactics, techniques, and procedures (TTPs) our forces need to make best, immediate use of new systems.


ASAS Journal 13 / SS P R INI N G h ttp:// 18 change. Furthermore, a simple probabilis tic approach to the elements of survivability can be misleading if operational co-dependencies are not considered; averaging probabilities across all operational scenarios will more than often result in an unreliable estimate of the probability of survival. Issue 2: Although survivability is divided into two major elements (susceptibility and vulnerability), aspects of it are typically assessed by three different entities. Some of the fundamental capabilities and performance of survivability-related system features are assessed during developmental test and evaluation (DT&E) as subsystems mature; however, evaluation of these subsystems as part of the whole acquisition product and in an operational environment is not normally performed until operational test and evaluation (OT&E). Although OT&E can be performed concurrently with DT&E efforts, concurrent testing is not necessarily integrated testing, and OT&E might discover problems in the perfor mance of survivability-related features when tested in operationally realistic environments that the requirements do not consider. Assessment of vulnerability is normally performed during live re test and evaluation (LFT&E), although some vulnerability-reduction features may be assessed during developmental and operational testing; however, LFT&E must ensure that test conditions correspond to operationally realistic scenarios for consistency with opera tional assessments. By itself, however, this architecture does not result in a comprehensive integrated assessment, and despite signicant test and evalua tion efforts, the lack of coordination and integration can signicantly depreciate the value of individual ndings. Issue 3: A balanced approach to integrat ing susceptibilityand vulnerability-reduction features in the aircraft is not always carefully considered in the system design process. The mix of survivability technologies or techniques and synergies between them is typically not optimized for a given platform. The design approach chosen early in the program directly inuences the extent to which susceptibilityand vulnerability-reduction are integrated. A distributed design approach can cause difculties in characterizing the inte grated effects of platform capabilities on overall survivability, naturally translating into disparate assessment approaches later in the acquisition process. Issue 4: A number of deciencies have been identied in the ability of open-air test ranges to support an integrated survivability assessment. Limited capabilities of the open-air test ranges was one of the deciencies listed in the 2003 JASP report on ISA. It was rightfully argued that range test data were not suitable for model validation. Consequentially M&S tools, which are glue that holds the integrated surviv ability assessment together, include uncertainties and are not credible enough to bring together various elements of the survivability assessment where those uncertainties will multiply. NN EW ISA ISA C oO N cC E pP TObjectiveIn an attempt to dene a more practical approach, DOT&E requested an example ISA concept to be developed for a current DoD program in each of three warfare areas (land, sea, and air). This resulted in a concept based on the premise that calculating all elements of the kill chain equation, as was attempted in previous ISAs, may not be necessary, allowing a program to avoid an overwhelming M&S effort and the associated deciencies. Current M&S and testing tools are not advanced enough to accurately determine the engagement, encounter, and endgame conditions necessary to achieve such an assessment. Furthermore, a more thorough look at the most signicant survivability factors in any pre-dened mission scenario would show that such a comprehensive assessment might be inefcient and limited to the conditions chosen. Rather, this concept eliminates the need to assess kill chain elements that do no signicantly impact the nal assessment and focuses on identifying and increasing the condence of the evaluation of the most signicant factors that affect survivability in realistic operational scenarios.MethodologyPlanning for a test and evaluation (T&E) program of any system should begin at the top level (Figure 1), with an under standing of the system, its critical components and functions, the opera tional deployment concept of the system, and its various mission scenarios. These might not always be complete early in the planning process, but they need to be understood by all evaluating organiza tions because they are critical in dening the common conditions under which the system will be assessed across the various acquisition stages. Otherwise, as similarly documented by the Defense Science Board and the National Academies, testing at disparate condi tions could hide failure modes and performance limitations that will then adversely affect the evaluation later in the program and potentially the acquisi tion decision.


19 h ttp:// AS AS Journal 13 / S S P R INI N GIntelligence information from system threat assessment reports and other capstone threat reports must also be evaluated to identify the expected threat types of concern, their capabilities, tactics, expected dispositions, and likelihood of encounter. These need to be coordinated across T&E organizations. Otherwise, assessing vulnerability and susceptibility at different encounter conditions will result in inadequate, individual data interfaces that prevent that data from being effectively com bined into meaningful top-level survivability conclusions. A practical ISA, proposed here, will determine how the critical threat capabilities, in the selected operational environments, might affect the perfor mance of each critical attribute of the platform at risk (e.g. signature, counter measures) and then the survivability of the same platform as a whole (e.g. effective employment against advanced threats). The threat kill chain, presented in Figure 2, can be used to help evaluate the survivability for the representative mission scenarios, but there should be no attempt to solve for each probability in the kill chain equation, since the prob abilities are extremely dependent on the scenario chosen and the encounter, engagement, and endgame conditions associated with that scenario. The presented kill chain can be more nely resolved to reveal specic threat kill mechanisms and platform survivability enhancement or countering features. EE xecutionIn many cases, this kill chain, and the platforms response to it, can be assessed by considering competing timelines: the threat timeline consisting of the elements corresponding to the time it takes to complete each kill chain element and the system timeline consisting of the time to recognize the threat and respond to it. Consider, for example, a hypothetical scenario in which an airborne intelligence, surveillance, and reconnaissance (ISR) aircraft without any installed countermeasures is targeted by a radio frequency (RF)-guided, surface-toair missile (SAM) system as shown in Figure 3. With an understanding of threat system capabilities, it might be possible to concede that, if hit, the ISR aircraft would not survive ( i.e., the threat is an overmatch). Survivability, in this case, will then depend on the strategies of knowing threat locations and avoiding engage ments or of quickly detecting and identifying the threat and retreating beyond threat range before an intercept occurs. Survivability will be reliant on a fast threat warning capability that accurately identies the threat and its location to prevent an intercept. In this particular case, the ISA would focus on the competing timelines for threat targeting of the aircraft and for aircraft recognition of the threat and response. While intelligence sources provide the necessary threat perfor mance data, the acquisition program will need to determine detection system response and accuracy, and aircraft aerodynamic performance for the retreat manevuer. The ISA strategy will identify the means required to make those determinations. For example, the competing timeline analysis, as shown in Figure 4, could use intelligence-based information for the threat in coordination with platform detection capabilities based on measured aircraft performance. From the kill chain perspective, the survivability assessment could, in this case, be focused on an assessment that carefully looks at selected kill chain time elements: the times for the threat to activate, detect, and track the aircraft, and launch and y out to a hit versus the times for the aircraft to detect and identify the threat, and maneuver and escape outside the threat lethal range. Other aspects of survivability, tradition ally captured by the kill chain, need not be addressed in this case because they Mission Accomplishment Survivability Suitability Effectiveness Figure 1 TopDown Scenario-based Approach Figure 2 Threat and Platform Competing Attributes


ASAS Journal 13 / SS P R INI N G h ttp:// 20 are not critical for this particular scenario and would not inuence the nal probability of survival estimate. A practical ISA includes similar analyses for other likely pre-dened scenarios. In the event the threat was not an over match for this system and other probabilities in the kill chain were non-zero, vulnerability elements would become critical to the survivability assessment and would have to be evaluated. Critical individual assessments would have to be combined to determine the signicance of each of these elements, and to provide an operator with an overall understanding of the conditions under which the system could outperform the threat and what tactics to employ to be successful. Individual elements alone, vulnerability or suscepti bility, cannot provide such information. SS ummary and I I mpactA key aspect of this approach is identify ing those kill chain elements critical to particular engagement scenarios and focusing the resources on increasing the condence in those specic elements rather than spreading them across the entire kill chain spectrum. Undeniably, this approach would not provide a quantied measure of survivability, but it would provide decision makers and soldiers with conclusions about the survivability of the system in its intended role, giving them a better understanding of the platform shortcomings and capabilities across the spectrum of missions in which it will be used. Additionally, the ISA could reveal areas that need further survivability enhance ments. The assessment conclusions could be used to recommend whether other threat-tolerance or avoidance capabilities should be provided to improve the aircraft survival rate ( e.g., in the hypothetical ISR aircraft scenario, installing RF counter measures might need to be considered if the timelines show that aircraft cannot escape outside the threat lethal range by detection and maneuvering). ISAISA ImpIMP LE mM E NTATI oO N II SSUESCoordination and CommunicationEfforts to assess various survivability elements fall under the responsibilities of different organizations. Some can be planned and tested independently of others, while others ( e.g., countermeasures effectiveness and probability of hit) are closely related and would require cross-organizational interactions and coordination. A hypothetical example on the various survivability critical compo nents and the responsible organizations is shown in Figure 5. Recent programs have shown that test responsibilities and data needs that cross organizational lines are likely places where problems can occur ( e.g., failure to plan for needed data or schedule effects that cause data to be generated too late to meet the needs of the other organiza tions). Legacy T&E practices include developmental testing (DT), operational testing (OT), and live re testing (LFT) strategies that are formed independently of each other. Additionally, tests are frequently conducted in isolation from related M&S efforts. These are some of the historic barriers that threaten successful implementation of any ISA approach, including the one outlined here. To avoid such problems, a clear framework for integrated assessments needs to be provided so that the guidelines for participation are clearly understood. Coordination and planning among DT, OT, and LFT&E, and between testers and modelers, are necessary at the beginning of the program to most effectively and comprehensively assess platform survivability. In all cases, the T&E organizations must coordinate their efforts to ensure that LFTs reect the operational use of the aircraft and that DT data are adequate and timely to support both LFT&E and OT&E. Threats and scenarios must be consistent within the survivability assessment in order to adequately fold into each other to provide the most meaningful nal assessment. Focusing on only the traditional scope of each organizations assigned tasks and assuming that, in the end, all elements will come together is not likely to contribute to a successful approach. EE stablished G G u idelinesTo facilitate a feasible and successful ISA approach, the details of the approach need to be carefully planned and documented in the test and evaluation Platform Survive Kill Threat tDetecttDetecttActivetClear tHittLaunchtTracktID tManeuver tEscape = tThreat = tHit -tActive tFly-OutRThreat/Lethal-Rp-8/IDVelp-8 Figure 3 Evasion of Inactive Pop-up RF-guided SAM Figure 4 Competing Timeline Analysis Given the System and Threat Capabilities


21 h ttp:// AS AS Journal 13 / S S P R INI N Gmaster plan, live re strategy, and any DT-related document guides. The respective documents should reect the coordination and communication needs, and should contain information that involves data transfer between the test organizations to ensure data needs are met. Continued emphasis on coordination will be needed and enforced throughout program execution by forming a Survivability Integrated Product Team, since schedule changes affect not only the acting organizations, but also those who are depending on the data they generate. C oO N cC LUSI oO NA practical ISA includes an assessment of the survivability of the aircraft against expected threats in the context of the missions it is ying. It focuses on a thorough study of the most signicant elements critical to the system survivabil ity in those missions. It does not involve an overwhelming M&S effort to provide the probability of survival calculations because such methodologies are currently not reliable and calculations of all kill chain elements might not even be necessary. Identifying the most critical factors that affect system survivability in any given scenario will eliminate the need to assess the elements of the kill chain that do not signicantly affect the nal assessment. Specic tools to evaluate the most critical elements of survivability for the particular scenario have to be identied in the relevant test plan documents while ensuring an adequate interface between the various elements. The data needs and data transfers between the various test organizations and modelers must also be documented so that they can transpire in a timely manner. Activities from each organization involved must complement the others so that the resulting data can be successfully combined to reach over-arching, systematic and coordinated survivability conclusions that benets both operators and decision makers. The success of any joint initiative cannot be expected unless it is advantageous for all parties to participate. An ISA concept must be developed as early as possible in the development of the system, prefer ably during the analysis of alternatives, but certainly no later than Milestone B or the program entry point, if it enters post-Milestone B. The ISA concept must highlight the interdependency of all organizations involved and lay out a plan that coordinates T&E efforts among the program and services, DOT&E, AT&L, and their contractors to achieve an end-to-end assessment of the overall survivability of the aircraft in operationally representative scenarios to adequately inform aircraft operators and to support an acquisition decision. RR eferences[1] The notation LFT&E Directed or OT&E Directed refers to the primary oversight responsibilities within DOT&E. Survivability Assessment Elements Assessment Scenario Definition Signatures Mission Planning System Effectiveness Off-board S/A Effectiveness Countermeasure Effectiveness Aircraft Performance System/Aircrew Interface and S/A Response Aircrew TTPs RF Threat Fly-Out IR Threat Fly-Out IR Threat Hit Points (HITL) Threat Tolerance (Vulnerability) Force Protection Reparability Non-conventional Threat Tolerance LFT&E Directed,OT&E Directed Susceptibility Vulnerability DTOTM &S M &S LFT &E Figure 5 Example of Shared OT&E and LFT&E Responsibilities


ASAS Journal 13 / SS P R INI N G h ttp:// 22 In 2006, in recognition of his professional accomplish ments, The Boeing Company awarded Dennis the distinguished title of Technical Fellow. On 31 March 2012, Dennis received the Golden Torch Lifetime Achievement Award from the National Society of Black Engineers at their national conference in Pittsburgh. This award recognizes those who have made signicant engineering impacts, served as role models for others, and helped advance opportunities for African Americans in industry. Dennis is currently the technical lead for vulnerability engineering on the P-8A Multi-Mission Maritime Aircraft and KK C -46 Aerial Refueling Development programs. In this position, he directs survivability and mission effectiveness analysis efforts in support of these military aircraft programs. He is a recognized expert in the eld of survivability analysis and live re testing, and is sought out to support key Boeing development programs and provide guidance where survivability of the design has been impacted. Dennis has many career accomplish ments, but one of the more noteworthy was his management and technical leadership of the Survivability Engineering Program for the EA-18G electronic attack aircraft developed for the Navy. Dennis led the analysis, demonstrating the high level of surviv ability of the design and its ability to meet specication requirements. Dennis worked with the Navy to develop program strategies to address the EA-18G design survivability critical issues using analysis and data from the earlier F/A-18E/F program. The results supported the decision to grant the EA-18G program approval to proceed into full rate production. Dennis feels his greatest accomplishment and personal satisfac tion comes from knowing he contributed to improving the survivability of military platforms, which translates into saving the lives of our young men and women who y aboard these aircraft. Dennis graduated from Voorhees College in 1981 with a BS in mathematics. While working full-time with Boeing, he earned an MS in mathematics with an operations research concentration from Southern Illinois University in 1988. A member of the American Institute of Aeronautics and Astronautics, where he serves on the Technical Committee for Aircraft Survivability, he published a paper in the Joint Technical Coordinating Group on Aircraft Survivability Journal titled Integrated Vulnerability and Product Safety Approach to Aircraft Survivability. He was also featured in an article in the St. Louis American Newspaper titled, Scientically Speaking. He has also written numerous technical reports for the Air Force and Navy as part of his job assignments. Dennis actively mentors Boeing engineers and interns in professional career development, including providing letters of references for employment, graduate school, and for awards recognizing the accomplishments of engineers. He tutors high school students as part of Boeings cooperative effort with the National Urban League Business to School Event. Dennis has also volunteered his time for the Habitat for Humanity and Rebuilding Together program, where he helped build and repair homes for needy homeowners. EE X cC ELLEN cC E I N S S U rv RV I vV A BILITY DD E NNIS W W I LLIA mM Sby Dale Atkinson The Joint Aircraft Survivability Program (JASP) take great pleasure in recognizing Dennis Williams for Excellence in Survivability. Dennis has over 30 years of experience in the Operations Analysis Department at The Boeing Company, supporting aircraft survivability efforts. He has conducted survivability and vulnerability analyses to support Air Force Fighter competition proposals and progressed to managing the vulnerability engineering programs for the Advanced Tactical Fighter, F/A-18E/F, and EA-18G development programs.


23 h ttp:// AS AS Journal 13 / S S P R INI N G Dennis is married to the former Dorothy Rice, who he met while they were both students in mathematics at Voorhees College, and who is also employed by The Boeing Companys IT Division. They have a son, Shawn, who is a student at University of Missouri. It is with great pleasure that JASP honors Dennis Williams for his Excellence in Survivability contributions to the technical community, the Joint Aircraft Survivability Program Ofce, the Survivability disci pline, and the soldier. JC ATAT C oO RNERcontinued from page 5 highest annual number of assessments conducted since 2003. Notable are four surface-to-air re (SAFIRE) events resulting in aircraft loss (ACLOSS), and another seven ACLOSS events happened as a result of both direct and indirect re ground attacks on coalition airelds. Four of the catastrophic loss events required the team to operate outside the wire, recovering critical material that led to an accurate assessment of platform loss mechanism. Additionally, there were several safety/mishap events where JCAT provided direct assistance to unit investigators. After the Service components review the JCAT assessment products, they are archived in the Survivability/Vulnerability Information Analysis Center database. JCAT assessments follow a deliberate process that has been rened over 9 years of combat deployments. By nature of the mission, JCAT assessors become deeply involved, collecting data and performing analyses that directly support the soldier. JCAT assessors in theater occupy a unique position that spans the Operations Analysis, Intel Collection, and Tactics Development regimes. Having a JCAT assessor with the right skill sets in theater at the conuence of these information streams can have synergistic effects. These effects were illustrated in August when USN Lieutenant Commander (LCDR) Pete Olsen delivered a Rotor/Tilt-Rotor SAFIRE Mitigation Study for the USMC 3d MAW(Fwd) Commanding General (CG) and United KK i ngdom Comander, Joint Aircraft Group Afghanistan (U KK COMJAG) that was operating at Bastion Aireld in Regional Command Southwest (RC-SW). Since Marines and British forces operate in RC-SW with high coordination, the study joined their ight hours, operations, intelligence, safety, and JCAT data over the period from 1 January to 31 July 2012. The overarching goal was to drive down hit rates and diminish enemy SAFIRE effectiveness. LCDR Olsen led working group meetings with weapons tactics instructors from the Marines and qualied helicopter tactics instructors from the British forces to review and rene the analysis to understand root causes. USAF combat search and rescue members also participated in this study. The team formed 13 key recommenda tions on where to focus to reduce operating susceptibilities. The study also validated current practices and further challenged conventional approaches to mission planning. Ultimately, this study was reviewed with aviation leaders, aircrews, and ground force representa tives to align understanding and improve tactics, technics, and procedures. Another major event in 2012 was JCAT support and performance during the aftermath of the 14 September 2012 base attack at Camp Bastion. Three JCAT key capabilities were tested and each validated response, joint coordination, and mission credibility. In the attack, three well trained, ve-man insurgent teams breached the base perimeter, split-up, and attacked personnel and aviation assets. This was the most signicant ACLOSS event for US Marines since the Tet Offensive in Vietnam.


ASAS Journal 13 / SS P R INI N G h ttp:// 24 In response, and working with all unit maintenance leads, LCDR Olsen provided the MAW(Fwd) CG and U KK COMJAG with an immediate consolidated battle damage picture of all aircraft. JCAT was then leveraged to support after-action efforts with maintenance, anti-terrorism/ force protection teams, and also preserve facts of signicance for the Marine Corps History Division, Headquarters Marine Corps. Faced with a high volume of work, USAF Captain (Capt) Gabe Jacobson redeployed from K K a ndahar Air Base and a joint coordination request to rapidly plus-up manpower was initiated to Colonel (Col) Mike Stephens at WrightPatterson Air Force Base. Within 72 hours, Lieutenant Colonel (Lt Col) Chad Ryther arrived at Leatherneck/Bastion and provided 10 days of direct support to the battle damage assessment process with LCDR Olson and Capt Jacobson. Lt Col Ryther received appreciation from the MAW(Fwd) CG for his support to the response. Lastly, with earned mission credibility and condence in the JCAT understanding and knowledge of events at the aireld, the MAW(Fwd) Chief of Staff tasked JCAT to conduct a post-attack events review for the visiting MAGTF Staff Training Program (MSTP) three-star General. The objective was to enhance situational awareness and bring forward lessons learned. The MSTP improves the warghting skills of senior Marine commanders and their staff prior to assuming command. In summary, the JCAT mission and its value to the Marine Corps remains conrmed as a valueenhancing capability to aviation soldiers. A new project was initiated this year by USN JCATthe development of a JCAT Training Range located at Naval Air Warfare Center Weapons Division (NAWCWD) China Lake, CA. China Lake has been the perennial training site for the JCAT Phase 2 class supported by the USN detachment at China Lake. Training is typically conducted using weapons damaged test aircraft that are parked in a fenced compound originally set up by the USAF JCAT group. This training has proven successful over the past 9 years and provides a good hands-on training experience for student JCAT assessors. A change in the training syllabus was introduced last year, which leveraged an actual F-4 crash site on the grounds of NAWCWD to provide a more realistic and challenging training experience. Based on the success of this exercise, the Ofcer in Charge of JCAT Det B CDR David Storr drew up a proposal and was granted 340 acres of China Lake range land to build a JCAT training range. The purpose of this range will be to stage realistic battle damage crash sites. The dimensions of the training range will allow for full size crash sites to be created, and the topography of the land will offer the possibility to stage notional ring positions related to the battle damage event, and will enhance realism and complexity of the training experience. Environmental and cultural surveys have been funded and are underway on the range. USN JCAT has an on-hand inventory of battle damaged test aircraft that can be used to populate the training range, and live re tests are continually being conducted at NAWCWD, which should provide a steady stream of test articles for JCAT assessors to train on in the future. During 2012, JCAT remained busy stateside as well. JCATs Army Component hosted the 2012 Threat Weapons and Effects Seminar at Eglin Air Force Base, FL, with almost 200 civilian and military personnel in attendance. This event demonstrated missile warhead effects against a transport category aircraft wing section and anti-tank guided missile damage to a static helicopter. Attendees included industry partners, six other US government agencies, and representitives from all US military Services. JCAT also provides professional training to the US aviation community. The pre-deployment training provided in the US by the Army component touched 1,100 aircrew bound for combat duty and another 1,200 in professional military education courses and Department of Defense symposia. Overall, JCAT provided training and education to more than 5,700 personnel and recorded more than 2,700 downloads from their SIPRNET K K n owledge Management sites. The JCAT mission enhances the Army Components tactics development duties as part of the Army Aviation Center of Excellence. This complementary role led to an additional 27,200 classied website downloads of JCAT and JCAT-inuenced documents pertaining to threat determi nation and survivability subjects. In addition to the CONUS training provided by the Army Component, the USAF and USN forward-deployed assessors provide real-time training to deployed units in theater. LCDR Pete Olsen performs a JCAT assessment at Camp Bastion, Helmand Province, Afghanistan (USMC /Released)


25 h ttp:// AS AS Journal 13 / S S P R INI N GIn recent years, the Pentagons Director for live re test and evaluation (LFT&E) has placed a greater emphasis on passenger survivability from combat threats as part of LFT&E, and he has asked multi-Service participants in the Joint Aircraft Survivability Program (JASP) to explore models and technolo gies that evaluate and improve crew and passenger survivability. A closer exami nation of cabin safety improvement efforts (along with their underlying assumptions and limitations) underway at the Federal Aviation Administration (FAA) might lead to cooperation between the JASP and the FAA in JASPs ongoing efforts to evaluate and improve combat survivability for military aircraft passengers. The FAA classies cabin safety into two distinct, but interrelated, categories: in-ight safety and post-crash survival. The primary focus of cabin safety is the safety and survivability of airplane occupants. FAA research activities aimed toward in-ight safety primarily address re hazards, but also include other activities, such as protection against turbulence, decompression, and human factors design practices, to reduce and mitigate passenger injuries ( e.g., no sharp edges or tripping hazards). Research activities aimed toward post-crash survival include crash (impact) protection, emergency evacuation, water landings, and post-evacuation survival, especially in harsh environments ( e.g., re, remote areas, water). JASP divides aircraft combat survivability improvement efforts into susceptibility reduction (lowering the likelihood of aircraft taking a hit) and vulnerability reduction (lowering the likelihood of aircraft loss after taking a hit). [1,2] Of these, vulnerability reduction is more closely related to the issue of cabin safety, especially when applied to passenger survivability. Many of the strategies and technologies used to reduce aircraft vulnerability (redundancy, separation, active and passive re suppression, etc.) are also used to increase aircraft safety. The major differences between the safety and survivability disciplines lie in the nature and probability of the threat. The threats to cabin safety are related to aircraft and passenger hazards during normal operations, which are typically minimized through safety regulations and Fire SuppressionFire SafetyVulnerability Reduction In-Flight Safety Susceptibility Reduction Post-Crash Survivability EvacuationCombat SurvivabilityCabin SafetySignature Reduction Counter measures Sensors Armor Design Engine Design Advanced Materials Crash DynamicsWater/ Environmental Survival TurbulenceDecompressionMedical AA IR cC REW C omO M BAT SS U RVIVABILITY AND CIVILIAN AA I R cC R A fF T C ABIN S S A fF E TY: EE xploring and E E x tending O O u r Common Groundby Joel Williamsen and Isidore Venetos Figure1 Dynamics of Improving Crew and Passenger SurvivabilityUS military aircraft are required to operate efciently in peacetime and effectively in wartime. Some of these requirements, including cabin safety, are common to both civilian airliners and military aircraft. Some attributes, including the combat survivability of aircraft and occupants to combat threats, are unique to military aircraft; however, many design attributes that improve cabin safety can also improve aircraft survivability.


ASAS Journal 13 / SS P R INI N G h ttp:// 26 polices. The risks are reduced by limiting hazardous conditions and improving the inherent reliability of components to stop those hazards once they occur. The hazard sources are, by nature, less intense and more unlikely than aircraft combat threats. Passive means ( e.g., the use of re retardant materials instead of automatic cabin re suppression to defeat cabin res) are often sufcient in civil aviation. Indeed, aircraft combat threats are designed to overcome the inherent safety features of an aircraft, and increase the probability of aircraft and passenger loss. Understanding the specic limits of military aircraft safety features (designed for peacetime used to be consistent with FAA regulations) might guide their application and improvement to reduce aircraft and passenger vulnerability to combat threats. AA NAL oO G oO US Go GO AL S WIT hH DD I ffF F E RENT App APP R o O A chC H E SThe primary responsibility of the FAAs in-house technical experts (at locations such as the William J. Hughes Technical Center near Atlantic City, NJ) is the development of reasonable safety standards and the test techniques to verify that these standards are met. It is up to the industry to develop technologies to meet those standards, using the test techniques developed by the FAA; however, in developing these standards, the FAA must thoroughly understand the art of the possible, and become heavily involved in the test of new technologies under development by industry, aca demia, and other areas of government. JASPs own mission is similar, but emphasizes the development of needed survivability-enhancing technologies over the development of standards. Some areas of common interest between cabin safety and survivability communities are described in Figure 1. JASP emphasizes the quantication of aircraft risk from combat threats as the basis for selecting the most promising technologies, and has just begun to extend those assessments to combat aircraft passenger injury risk. The FAA, on the other hand, uses the study of past accidents (and the identied sources of passenger casualties) as the primary basis for the establishment of new standards and technologies. [3] Although JASP has started to collect the potential sources for casualties in aircraft combatrelated crashes within current theaters of operation, their efforts to study the causes of passenger casualties from past crash events are only just beginning. If military aircraft crashes caused by enemy threats are similar in casualty production to civilian airliner casualties, the FAAs long record and deep understanding of past civilian accidents (crashes, hard landings, aircraft res, etc. ) could help JASP get a head start on developing passenger survivability technologies. These areas may include the use of re retardant materials, re and smoke sensors, emergency lighting, egress (door) designs, and in-cabin storage solutions (to speed egress and reduce blunt trauma) within passenger spaces. TT RAINING AND SS T ANDARDS ARE PART of OF T hH E So SO L UTI oO N While the FAA studies civilian casualty production, with the basis of their standards possibly aiding JASP in identifying areas for reducing military aircraft passenger casualties following ballistic attack, it is possible that military casualty production is more sudden and severe than casualties produced in civilian airliner accidents. A deep understanding of the FAAs assumptions made in establishing safety standards, including the intensity of civilian passen ger hazards and the efcacy of existing equipment, could lead to needed enhancements of that equipment (or its rejection for use in military applications as too little, and not sufciently weight effective for military application). It is also possible that marginal technical solutions that have not yet been imple mented as standards by the FAA were rejected for reasons that would not necessarily apply to military aircraft passengers. For example, the FAA has so far rejected the widespread passenger use of gas hoods for reducing smokerelated casualties following a cabin re, largely because of the difculty in training a wide sector of the public in their use prior to each ight. Training of younger, warghting passengers may be easier, and raise the utility of these technologies. It is also possible that the sources and intensity of smoke and re in military aircraft cabins following ballistic attack could further justify their use (compared to civilian airliners). The FAA has also had a very successful history of improving passenger survivabil ity through the policies and regulations it has mandated on the civilian aerospace sector. The standards are often based on the extensive testing along with costbenets analysis with a metric of the number of lives saved. FAA economists evaluate the cost implications of the standards prior to any approval. JASP can leverage this experience of developing effective standards while the FAA can benet from the live data that is often gathered by JASP in live re demonstrations. As important as technology is in reducing passenger casualties, improved training and operations can do as much or more to reduce passenger casualties following a crash or hard landing. In addition to the example of training for the use of gas hoods (above), the training for how best to egress a military aircraft following an


27 h ttp:// AS AS Journal 13 / S S P R INI N Gemergency landing is another example of how the FAA could enlighten existing practice. How often are soldiers trained to properly egress their aircraft in an emergency, considering the heavy personal equipment that they carry? Experience in the test of the Joint Cargo Aircraft in 2009 indicated that egress time of fully outtted troops through a side door could decrease by 40% if the troops were told what to do with their equipment prior to egress. [4] What could further tests do to improve egress time? What would improved egress times mean to passenger survivability for aircraft? And, how could FAA experience help JASP answer these questions?KEY PARTNERS hH I pP DD E VEL opO P M ENTRecent technical exchanges between JASP and FAA technical representatives indicated a wide potential for future combined programs to improve safety and survivability, including: „ T est and evaluation of re-resistant materials aboard combat aircraft „ T est and standards development for biofuel vulnerability „ P hysics-based re model develop ment and validation testing „ F ire tests in explosive-resistant variable altitude chambers, including oxygen bottles, lithium batteries, and other hazardous aircraft components „ T est of aircraft wings or other components to transonic loads and re hazards at altitudes up to 15,000 feet „ T est of pressurized (stressed skin) panels to catastrophic fracture under aws (and potentially impact loading) „ U se of a variant of the recent JASP crew and passenger survivability models to quantify and improve civilian passenger safety „ Use of full scale, post-crash re facilities for civilian and military aircraft The areas highlighted represent only a fraction of FAA and JASP opportunities that were recently observed through meeting with FAA technical experts and touring the FAA William J. Hughes Technical Center. More opportunities for joint programs are likely to be uncovered at the FAAs other facility at the Civil Aeromedical Institute in Oklahoma City, O KK w hich specializes in passenger cabin hazard level prediction, enclosure design, passenger tolerance levels, and egress testing and modeling. Given the tight scal restraints that all government agencies are facing, along with the commonalities described, JASP and the FAA should consider increased coopera tion to improve each organizations aircraft and occupant survivability programs along with the common usage of test facilities for both the civilian and military sector. RR eferences: [1] http://www.aircraft Denitions.html [2] B all, Robert E., The Fundamentals of Aircraft Combat Survivability Analysis and Design, Second Edition, AIAA, Reston, VA, 2003 (The AIAA Textbook). [3] [4] C ripps, Brandon, 2009. Daily Report, HFE Egress Testing; Static Line Paratroopers, C-27 JCA Aircraft #27011, Y Y u ma Proving Grounds, May 28, 2009 [5] F ire Cabin Safety Researcha Perspective, Maher K K h ozam, Requlatory Standards, aircraft certication transport Canada, NOV 2004 (4th Triennal Intl Fire & Cabin Safety Research Conference)


ASAS Journal 13 / SS P R INI N G h ttp:// 28 CREW C ompOMP A RT mM ENT FIRE SS U RVIVABILITY T T E STINGby Patrick OConnell and Adam Goss Vulnerability testing has shown that ballistic impacts of fuel and hydraulic lines can result in a sustained re in the crew compartment; however, in these vulnerability tests, the re was seldom allowed to burn for more than 10 to 15 seconds before being extinguished by test range reghting equipment. The res effect on the crew was usually not evaluated. To assess crew effects, the environment inside the crew compart ment, from re ignition to landing/egress, needs to be assessed for survivability. While attempting to dene the environ ment throughout a typical transport aircraft interior during threat-induced re events, the parameters of temperature, air toxicity (oxygen [O2] depletion and carbon monoxide [CO] concentration), and visual obscurity were selected as the primary environmental data to collect over time until certain criteria were reached, indicative of crew incapacitation or structural degradation of the platform. Quantifying the heat and CO environment was of particular interest as these have signicant physiological implications. In general, when the CO concentration rises above 12,800 parts per million (ppm), immediate physiological effects, unconsciousness, and danger of death occur within 1 to 3 minutes. Also, as the air temperature approaches 203 o C (397 o F), the body starts to physically shut down the respiratory system, which can become irreversibly damaged. This 3-year test program, accomplished from 20102012, was a collaborative effort between the Air Force (96 TG/ OL-AC at Wright-Patterson Air Force Base, OH) and the Army (Army Research Laboratorys Survivability/Lethality Analysis Directorate [ARL/SLAD] at Aberdeen Proving Ground, MD), and was sponsored by the Joint Live Fire (JLF) Aircraft program. Testing occurred at the Air Forces Aerospace Vehicle Survivability Facility from MarchJuly 2012. OB jJ E cC TIVEThe primary test objective of this JLF program was to generate data necessary to evaluate crew vulnerability during a sustained aircraft compartment re. Data was collected to gather information required to answer the following overarching questions: „ H ow long does the crew compart ment remain habitable if a re occurs? „ C an the aircrew continue to perform their duties if a sustained re occurs, and for how long? „ C ould the aircraft crew safely egress upon landing with a re aboard?CREW C ompOMP A RT mM E NT FIRE T T E STBEDAn H-3 helicopter hulk, located at ARL/ SLAD, was selected as the testbed for this program. The H-3 was a good candidate for the re testbed primarily because its interior crew compartment is Due to the many combat incidents involving helicopters during the Afghanistan and Iraq conicts, the Director, Operational Test and Evaluation (DOT&E) and the aircraft vulnerability community has increased their efforts to assess and improve aircrew survivability. For the purpose of this article, the aircrew is dened as all air vehicle occupants to include the pilot, co-pilot, aircrew, and passengers. Historically, during vulnerability testing of aircraft, little attention was given to assessing the crews survivability. The crew was primarily addressed during vulnerability modeling and given the same importance as any other critical component on the aircraft. Today, more emphasis is placed on assess ing crew vulnerability during testing, including assessing personnel injuries and fatalities related to direct hits, synergistic damage mechanisms, crash landings, or the inability of the crew to egress the aircraft after landing or crashing.


29 h ttp:// AS AS Journal 13 / S S P R INI N G large enough to represent a variety of xed and rotary wing aircraft. In addition, the H-3 features two access points, a forward side door and an aft ramp, which can be used in future evaluations of different airow congurations and to evaluate emergency egress options. Due to limited resources, the rotorcrafts external doors, including the cargo ramp and windows, were all closed for this initial test; there was also no induced airow, either externally or internally. Such aircraft congurations will be addressed in future testing. To allow for repeated re testing, modications included making the oor and two test locations, one forward and one aft, more robust to withstand prolonged re exposure. Steel re pans, heat shields, and structural supports were installed to ensure that prolonged and repeated re tests could be con ducted (refer to Figure 1). Further protective measures included an air evacuation system, an internal and external range reghting carbon dioxide [CO2] system, and a water shower system. The evacuation system clears the interior of any toxic fumes or smoke by activating an exhaust fan mounted atop the structure, coupled with four motor ized damper vents on the fuselage corners for fresh air intakes. CO2 nozzles were mounted around the aircraft exterior and throughout the interior, including the cabin cockpit and sub-oor dry bays, to extinguish sustained res and cool the structure. Also, a 2-inch water pipe was positioned over the longitudinal centerline of the fuselage, and activated as a secondary measure to the CO2 system if skin temperatures reach an upper limit. The test xture was designed so that it could be returned to a baseline conguration for each test. Commercial off-the-shelf nozzles, designed for use in residential furnaces, were employed in conjunction with an aircraft igniter for repeatedly igniting controlled sprays of JP-8 fuel and hydraulic uid (refer to Figure 2). Several sizes and types of these nozzles were pretested to select the most reliable units for igniting and sustaining res. One small and one large hook-type nozzle were selected to represent small and large uid line punctures from various sized threat impacts. Actual ballistic shots were unwarranted in this test since the objective concerned only the post-ignition re environment. Use of these nozzles removed the inherent variability of ballistic shots, allowing for controlled, repeatable re conditions. Follow-on testing will be accomplished to correlate the nozzle output with actual ballistic damage to fuel system components. DD ATA Ac AC QUISITI oO NTo quantify the environment inside the crew compartment during the progres sion of a re, three different types of data were collected: temperature, O2 and CO gas concentration, and visual data. An instrumentation system was designed to collect this data consistently and accurately. Temperature time histories were collected from 103 thermocouples to obtain a temperature prole within the crew compartment throughout the re duration. These sensors were mounted in 3x3 arrays (three ceiling level, three mid-height, and three oor level) at 10 different sections along the fuselage. Additional thermocouples included one each for the pilot and copilot, while other thermocouples monitored the H-3s structure for hidden res or heat damage. Four pairs of O2 and CO sensors, capable of providing real-time concentration data, were mounted strategically throughout the testbed. One pair was positioned in the cockpit where the copilots head would be. Three other pairs of gas sensors were positioned in the passenger compartment, both at ceiling and oor level, as indicated in Figure 3. Eight video cameras were installed throughout the cockpit and fuselage to provide complementary data to the temperature proles and record the re events, and also subsequent visual obscuration to fully understand what crew members would see during the re. Visual obscurity for the pilot is assessed using a laser diode emitter and detector along with the pilots camera view (camera 2). The laser sensor and camera are co-located where the pilots head would be, and both are pointed at the instrument panel. Correlating the pilot camera with the change in the diodes output can provide a quantitative Figure 1 Fire Pan and Heat Shield Design Figure 2 Aft Test Location


ASAS Journal 13 / SS P R INI N G h ttp:// 30 assessment to the pilots visibility over the course of a re event. A decrease in diodes output voltage corresponds to a decrease in visibility. All instrumentation and test equipment on the testbed was controlled through LabView. LabView is a graphical user interface (GUI) that was developed to provide real-time test data and control during the test (refer to Figure 4). The indicators representing thermocouples change color according to the tempera ture scale at the bottom of the gure. To monitor exact temperatures on one of 10 rail sections, the desired section may be viewed in the exploded window near the tail of the fuselage. In the example provided, Rail Section 1 is selected with the maximum temperature at any given time, and is automatically outlined in red. The Cockpit and System Instrumentation windows monitor all other data, including gas concentrations, uid temperatures and pressures, and the laser sensor. This program also provides a play-back feature of the test for post-processing. Test res were sustained until a condition indicative of aircrew incapacitation (pilot and co-pilot), aircraft loss (skin tempera ture above 900 o F), or a total test time of 5 minutes was achieved. Specically, aircrew incapacitation conditions consisted of a cockpit temperature above 400 o F, a CO toxicity level above 12,800 ppm, or a depletion of O2 to less than 12%. TT ESTING Accomp ACCOMP L IS hH E DIn total, 20 JP-8 tests were successfully accomplished, and 14 of 20 planned hydraulic tests were conducted. Six high-pressure hydraulic tests were skipped to preserve the test article structure due to rapidly escalating temperatures in these res. Both the small and large nozzles were used in the test cases with the fuel being pressurized to 30, 65, and 100 pounds per square inch (psi) to represent a variety of aircraft types from helicopters to larger xedwing aircraft. The hydraulic uid was tested at 50, 1,525, and 3,000 psi, represent ing both return and fully pressurized lines. DD ATA A A NALYSISAll the numerical data collected for each test run was graphed to simplify analyzing the environment inside the crew compartment during the test re and help answer the initial question of crew survivability. Thermocouple data was compiled into a series of graphs for each test to indicate the temperature prole at each of the 10 sections of the crew compartment and the cockpit. Toxicity plots that displayed O2 depletion and CO accumulation were also gener ated for each test. Refer to Figure 6 and 7 for examples of these graphs. All together, these plots can be used to analyze the test environment throughout the crew compartment during an event. Finally, video images inside the crew compartment during the test are provided alongside corresponding screen captures of the LabView GUI to correlate tempera ture and toxicity data with visibility. A survivability assessment for the crew was accomplished for each test condition in the enclosed aircraft conguration. Survivability was dened as enough time for the aircrew to land the aircraft and to egress. OBSERVATI oO NSFor JP-8 res, the large nozzle, highpressure condition appeared to be a threshold for survivability. Fire conditions at this threshold create a hazardous Figure 3 Instrumentation Locations within Crew Compartment Figure 5 Example of the Visual and Instrumentation Data Collected Figure 4 Crew Compartment LabView GUI


31 h ttp:// AS AS Journal 13 / S S P R INI N Genvironment in the crew compartment too quickly for personnel to react before reaching physiological limitations. Below this threshold, personnel have time to extinguish the re before losing con sciousness. Similarly, high pressure hydraulic conditions for both the small and large nozzles create hazardous environments that would not be survivable in this baseline aircraft conguration. Fires from low pressure hydraulic uid are much less severe and self-extinguished in most cases. For sustained low pressure hydraulic res, crew personnel would have ample time to extinguish them. Overall, cockpit O2 depletion is generally the rst condition rendering the pilots incapacitated, which would lead to an aircraft loss. O2 in the crew cabin followed the same depletion trend as in the cockpit, but with a faster rate near standing height and a slower rate near the oor. With the larger res, O2 depletion to below the 12% threshold can occur very quickly, and it is doubtful that a crew member could react fast enough to extinguish the re. CO levels also climbed near dangerous levels in a few tests, but none of the tests were ended due to high CO levels. The small nozzle usually created re events that were considered survivable by the aircrew, allowing enough time for them to land the aircraft and to egress. The hydraulic re tests produced more extreme events compared to the JP-8 res and presented a signicant threat to both personnel and the structural integrity of the aircraft. Future tests will be accomplished with hydraulic tubing to conrm that the intensity was not just the result of using a nozzle, but a result of the uid burning properties. The completely closed conguration of the testbed during the tests must be considered as a limitation to this assessment as effects of airow or aircrew actions, such as opening the door or windows, were not measured factors. C oO N cC LUSI oO NThis testing successfully achieved the objective set forth, providing initial data for completing a baseline assessment of aircrew vulnerability to re, and also for establishing the foundation for future crew compartment re survivability testing. Further testing will be conducted this year to explore the effects of aircraft conguration and ventilation on the severity of crew compartment res, and whether crew survivability can be improved by operational measures. Also, a detailed study will be conducted to determine the effectiveness of portable re extinguishers currently found in most aircraft crew compartments. Advanced re extinguishers, with either different dispensing technology or advanced extinguishing agents, will be evaluated. Through the combined efforts of 96 TG and ARL/SLAD, this JLF program produced a solid foundation upon which future aircrew vulnerability assessments can be based. Results will lead to improvements in aircrew and air vehicle survivability. Figure 6 Thermocouple Data for Aft Section of Crew Compartment Figure 7 Oxygen Concentration Depletion during a Test


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