MARBLES Plus B52 ASC RFI 11SEP2024 - Amendment 1.pdf

Modular Aircrew Restraint, Back and Leg Support (MARBLES) and B-52

Advanced Seat Cushion (B-52 ASC)

Request for Information (RFI) # FA8606-24-R-2009

General Introduction:

1. This announcement constitutes a Request for Information (RFI) only. Air Force Life Cycle

Management Center (AFLCMC) Human Systems Program Office (AFLCMC/WNU) is conducting a market assessment to identify potential sources and companies that may possess the expertise, capabilities, and experience to respond to the requirements listed in this document.

AFLCMC/WNU is issuing this combined RFI to explore innovative and cost-effective options to provide this capability and to obtain valuable feedback on the requirements for the Modular

Aircrew Restraint Leg, Back and Leg Support (MARBLES) and B-52 Advanced Seat Cushion

(ASC). This RFI is issued solely for information and planning purposes and will be considered to determine the acquisition strategy for the United States Air Force (USAF) MARBLES and B-52

ASC solutions as well as potential future solicitation.

2. This is not a request for competitive proposals. AFLCMC/WNU is not seeking proposals at this time and will not accept unsolicited proposals. Respondents are advised that the government will not pay for any information or administrative costs incurred in response to this RFI. Please be advised that all submissions become Government property and will not be returned. All costs associated with responding to this RFI will be solely at the responding party’s expense.

3. This RFI does not commit the Government to reply to the information received, or to later publish a solicitation, or to award a contract based on this information.

4. Respondents may be contacted if additional information is needed to fully understand the marketplace and/or comments to the requirements presented below.

Background:

The current use Personnel Clothing Unit (PCU)-15 and PCU-16 torso harnesses, Advanced Concept

Ejection Seat (ACES) cushion and back cushion, Miscellaneous Unit (MXU)-22/Parachute (P) lumbar pad and B-52 seat cushions utilized by USAF aircrew were developed in the 1960s. The MARBLES program is calling for solutions that utilize modern innovations and industry practices to improve upon the existing harnesses and cushions. The B-52 ASC program is calling for solutions to improve upon the existing B-52 seat cushions. AF aircrew report significantly higher chronic neck, shoulder, and back injuries than general AF population. Contingency and future operations may require aircrew to fly longer missions and wear additional torso mounted equipment further increasing potential fatigue, discomfort, and injury. The expected result of the MARBLES effort is a modular, integrated solution that will improve aircrew comfort, resilience, and safety during flight. The expected result of the B-52 ASC program is a new seat cushion which will improve B-52 aircrew comfort, resilience, and safety.

Purpose:

The purpose of this RFI is to gather information on the current state and availability of vendors who can provide items that can meet USAF requirements for the MARBLES and B-52 ASC programs as discussed in the requirements below. These requirements are not all encompassing but are currently considered the most critical in determining item suitability.

1. MARBLES & B-52 ASC

a. The MARBLES system is to consist of four distinct components: Torso Harness, Seat

Cushion, Back Cushion, and Lumbar Pad.

b. B-52 ASC is to consist of only a seat cushion component.

c. MARBLES shall apply to the ACES equipped aircraft including but not limited to: F-15, F15EX, F-16, F-22, A-10, B-1, and B-2.

d. B-52 ASC shall apply only to B-52 ejection seats.

e. MARBLES & B-52 defined legacy systems include but are not limited to:

i. Current torso harnesses used with ACES:

ii. Current ACES seat cushions:

iii. Current ACES back cushions:

iv. B-52 current ejection seat cushion: P/N 194-780127.

f. MARBLES & B-52 ASC shall require no modification of aircraft.

g. MARBLES & B-52 ASC shall accommodate the aircrew population to be defined as 98% of USAF male and female aircrew with the Joint Strike Fighter Civilian American and

Designation Basic Assembly

P/N Typical Fit

PCU-15 68J369

5th to 95th percentile

PCU-16 38J370

Less than 5th percentile

Part Number Config Rev Platform

831711 -403 B-1B

J119126 -501 F F-15, F-16, A-10

37324 F-22

Part Number Config Rev Platform

831792 F B-1B

J115982 -501 K F-16, F-15, A-10

J109707 -509 C F-22

European Surface Anthropometric Resource (JSF CAESAR) United States (US) Sample

Multivariate Cases 1 through 8 (AFRL-HE-WP-2003-0142).

h. MARBLES & B-52 ASC components may be supplied in different sizes to accommodate differing bodily proportions.

i. MARBLES & B-52 ASC shall not increase time for aircrew emergency ground egress from supported aircraft compared with legacy systems.

j. MARBLES & B-52 ASC shall not reduce aircrew reach to cockpit controls compared to legacy systems.

k. Testing with Anthropometric Test Dummy (ATD or “manikin”) utilizing MARBLES &

B-52 ASC shall not exceed aircrew injury thresholds (reference CSB-002 rev. A and

MIL-HDBK-516C):

i. During live-fire ejection by temperature-controlled component testing at +70°F, Dynamic Response Index +Z-Axis (DRZ) shall not exceed 18.0

ii. During live-fire ejection by temperature-controlled component testing at +165°F, DRZ shall not exceed 22.0

iii. Maximum allowable standard deviation across multiple live-fire tests shall be

1.0.

iv. Forces transmitted to occupant from a Vertical Drop Test (VDT) at 12G shall not exceed:

1. DRZ of 18.0 at any time.

2. 1000 lbs. imparted to lumbar of 5th percentile size and weight ATD.

3. 1500 lbs. imparted to lumbar of 50th percentile size and weight ATD.

4. 2200 lbs. imparted to lumbar of 95th percentile size and weight ATD.

l. MARBLES & B-52 ASC shall not displace the seated aircrew more than ±2 inches from the thrust line of the ejection seat (reference MIL-DTL-9479E, 3.2.17.1 and Figure 2) compared to legacy systems.

m. MARBLES & B-52 ASC shall endure environmental testing (IAW MIL-STD-810H

Change 1; “Environmental Engineering Considerations and Laboratory Tests”; 18 May

2022):

i. To include air pressure (altitude), explosive decompression, exposure to rain, operating temperature range (-65°F to +165°F), temperature shock, electrical surface resistivity, solar radiation, dust, sand, and fungi.

n. MARBLES & B-52 ASC materials selection shall be tested IAW 14 CFR 25.853

Appendix F Part I(a)(1)(ii):

i. MARBLES & B-52 ASC materials average tested burn length shall not exceed

8 inches.

ii. MARBLES & B-52 ASC materials average tested burn time shall not exceed

15 seconds.

iii. MARBLES & B-52 ASC materials average tested dripping flame time shall not exceed 5 seconds after falling.

o. MARBLES & B-52 ASC shall be sustainable and transportable within existing USAF and Defense Logistics Agency (DLA) infrastructure.

p. The contractor shall provide documentation including:

i. Component level detail drawings.

ii. Manufactured assembly detail drawings.

iii. Operation/Operator instructions

iv. Troubleshooting guides or troubleshooting instructions

2. ACES Torso Harness System:

a. Safety & Egress:

i. ACES Torso Harness shall provide for attachment to ACES structure.

ii. ACES Torso Harness shall provide for attachment to ACES parachute by two canopy release points of:

1. Koch Gen II Canopy release (P/N 990010-1 / 990010-9) or Frost Canopy release (P/N 81116-10).

iii. ACES Torso Harness shall restrain aircrew in the event of a crash.

1. ACES Torso Harness shall withstand 40G forward crash testing with 95th percentile ATD.

iv. ACES Torso Harness shall remain releasable by aircrew and emergency responders following crash testing.

v. ACES Torso Harness shall maintain all aircrew ejection sequence functions in live-fire ejection sled testing of the escape envelope of 0 to 600 Knots Equivalent

Airspeed (KEAS):

a. ACES Torso Harness shall restrain aircrew to ejection seat during catapult phase of ejection.

i. At applicable airspeed, Torso Harness shall restrain aircrew to ejection seat during drogue parachute phase

b. ACES Torso Harness interface to the ejection seat shall release aircrew from seat during ejection phase Seat-Aircrew-Separation

(SAS).

c. Following SAS, ACES Torso Harness shall maintain aircrew attachment to ejection seat parachute.

b. Construction & Materials:

i. ACES Torso Harness system shall weigh less than 5.6 lbs., excluding attached aircrew flight equipment (AFE) Subassemblies.

ii. ACES Torso Harness shall have a designed safety factor minimum 1.5x of the forces the ACES Torso Harness system experiences during crash and ejection, until aircrew is safely released from ACES Torso Harness.

iii. ACES Torso Harness attachment to parachute risers shall withstand parachute opening shock forces through parachute risers: 4500 lbf minimum on a single riser and 6000 lbf minimum total riser force.

iv. ACES Torso Harness restraint and strength shall not be compromised by environmental conditions: operating temperature range, temperature shock, precipitation exposure, or solar radiation

c. Aircrew Population Compatibility:

i. ACES Torso Harness shall be adjustable to fit tightly to individuals’ torso and leg proportions in the aircrew population.

ii. ACES Torso Harness may be supplied in differing sizes to accommodate differing anthropometric cases of the aircrew population.

d. AFE Compatibility:

i. ACES Torso Harness shall not interfere with the wearing and use of aircrew flight clothing, Multi-Climate Protective System, mask equipment, helmets and

Helmet-Mounted Devices (HMD), anti-exposure suits, Anti-G garments, Chemical Biological Radiological Nuclear equipment (CBRN), survival vests and life preservers.

ii. ACES Torso Harness shall provide for secure attachment and use of AFE

Subassemblies:

1. HMD connectors include but are not limited to Night Vision Goggles

(NVG) and Joint Helmet Mounted Cueing System (JHMCS).

2. Attachment locations compatible with oxygen connectors CRU-60/P, 94/P, 120/A, 122/A shall be placed to accommodate limited length oxygen hoses.

3. ACES Torso Harness shall provide for the attachment of PCU-10/P (P/N

8140561-10) or PCU-11/P (P/N 66E1697) Personnel Lowering Device

(PLD) in the lumbar area.

a. Torso Harness attachment for PLD V-ring (P/N PS27765-1) shall support weight of aircrew and equipment of at least 350 lbs.

b. Torso Harness shall provide for the attachment of the PLD

Hardware Pocket accessible to aircrew.

c. Torso Harness shall provide for the attachment of the PLD

Hardware Lanyard which limits the possibility of entanglement with other objects.

4. ACES Torso Harness strapping, components, and parts shall not obstruct bladder relief use for both male and female aircrew.

5. Other accessories include but not limited to minimum survival kit SRU-

16/P; distress marker light pocket; emergency radio beacons AN/URT-

33, AN/URT-44, and AN/URT-46.

e. Service Life:

i. ACES Torso Harness shall have a shelf life not less than 3 years.

ii. ACES Torso Harness shall have a service life not less than 7 years and not to exceed 10 years from date of manufacture.

3. ACES Seat Cushion System:

a. ACES Seat Cushion shall be supplemental or replacement for ACES current seat cushion or attachable to ACES Torso Harness (including ACES current torso harnesses PCU-15/P and PCU-16/P).

i. If attached to the ACES pan, ACES Seat Cushion shall provide attachment points requiring no modification to the ACES.

ii. ACES Seat Cushion design shall not obstruct the aircrews’ full range of motion of supported aircraft’s adjacent controls and connections.

1. Controls layout and orientation varies by supported aircraft and to include but not limited to stick, harness release, and ejection controls.

iii. ACES Seat Cushion removal and installation shall not require use of special tools.

iv. ACES Seat Cushion maintenance and cleaning shall not require removal of the ejection seat from the aircraft.

b. ACES Seat Cushion shall not weigh more than 5.0 lbs.

c. ACES Seat Cushion shall reduce aircrew reported discomfort on sorties ranging up to 14 hours.

i. Baseline: 39% of male aircrew reported discomfort after sortie.

ii. Baseline: 54% of female aircrew reported discomfort after sortie.

iii. ACES Seat Cushion reduction of discomfort shall be verified together with

ACES Back Cushion and ACES Lumbar Pad.

d. ACES Seat Cushion shall reduce aircrew seated pressure points (“hotspots”) compared to

ACES current seat cushion.

i. Seat Cushion pressure points shall be verified by pressure mapping testing utilizing representative aircrew population.

e. ACES Seat Cushion shall not increase risk of aircrew injury during ejection compared to

ACES current seat cushion.

i. ACES Seat Cushion risk of aircrew injury shall be verified together with ACES

Back Cushion and ACES Lumbar Pad.

ii. ACES Seat Cushion risk of aircrew injury shall be verified by live-fire sled utilizing ATDs 5th and 95th percentile.

f. ACES Seat Cushion shall have a shelf life not less than 6 years.

g. ACES Seat Cushion shall have a service life not less than 3 years.

4. ACES Back Cushion System:

a. ACES Back Cushion shall be supplemental or replacement for ACES current seat back cushion or attachable to ACES Torso Harness (including current torso harnesses PCU-

15/P and PCU-16/P).

i. ACES Back Cushion system shall provide cushioning for occupant middle/upper back (thoracic) and shoulders.

ii. ACES Back Cushion removal and installation shall not require use of special tools.

iii. ACES Back Cushion maintenance and cleaning shall not require removal of the ejection seat from the aircraft.

b. ACES Back Cushion shall not weigh more than 4.0 lbs.

c. ACES Back Cushion shall reduce aircrew reported discomfort on sorties ranging up to 14 hours.

i. ACES Back Cushion reduction of discomfort shall be verified together with

ACES Seat Cushion and ACES Lumbar Pad.

d. ACES Back Cushion shall not increase risk of aircrew injury compared to ACES current seat back cushion.

i. ACES Back Cushion risk of aircrew injury shall be verified together with ACES

Seat Cushion and ACES Lumbar Pad.

e. ACES Back Cushion shall have a shelf life not less than 6 years.

f. ACES Back Cushion shall have a service life not less than 3 years.

5. ACES Lumbar Pad System:

a. ACES Lumbar Pad shall be supplemental or replacement for ACES current seat back cushion and/or attachable to ACES Torso Harness (including current torso harnesses

PCU-15/P and PCU-16/P).

i. ACES Lumbar Pad system shall provide cushioning for occupant lower back

(lumbar).

b. ACES Lumbar Pad shall not weigh more than 2.0 lbs.

c. ACES Lumbar Pad shall reduce aircrew reported discomfort on sorties ranging up to 14 hours.

i. ACES Lumbar Pad reduction of discomfort shall be verified together with ACES

Seat Cushion and ACES Back Cushion.

d. ACES Lumbar Pad shall not increase risk of aircrew injury compared to ACES Current

Seat Back Pad.

i. ACES Lumbar Pad risk of aircrew injury shall be verified together with ACES

Seat Cushion and ACES Back Cushion.

e. ACES Lumbar Pad shall have a shelf life not less than 6 years.

f. ACES Lumbar Pad shall have a service life not less than 3 years.

6. B-52 ASC System:

a. B-52 ASC shall be supplemental or replacement for B-52 current seat cushion.

i. B-52 ASC shall provide attachment points requiring no modification to the B-52

Ejection Seat and B-52 Ejection Seat Survival Kit lid assembly (P/N 024-

750088).

ii. B-52 ASC design shall not obstruct the aircrew’s full range of motion of B-52’s adjacent controls and connections.

1. Controls layout and orientation may vary by aircrew function and to include but not limited to items such as stick and ejection controls.

iii. B-52 ASC removal and installation shall not require use of special tools.

iv. B-52 ASC maintenance and cleaning shall not require removal of the ejection seat from the aircraft.

b. B-52 ASC shall weigh not more than 4.0 lbs.

c. B-52 ASC shall reduce aircrew reported discomfort on sorties ranging up to 36 hours.

i. Baseline: 39% of male aircrew reported discomfort after sortie.

ii. Baseline: 54% of female aircrew reported discomfort after sortie.

d. B-52 ASC shall reduce aircrew seated pressure points (“hotspots”) compared to B-52 current seat cushion.

i. B-52 ASC pressure points shall be verified by pressure mapping testing utilizing representative aircrew population.

e. B-52 ASC shall not increase risk of aircrew injury compared to B-52 current seat cushion during ejection.

f. B-52 ASC shall have a shelf life not less than 6 years.

g. B-52 ASC shall have a service life not less than 3 years.

Guidance:

When a respondent submits their information, they need to:

1. Clearly demonstrate your ability to meet the requirements listed above. Please provide the current product specifications, capabilities and any relevant data to prove its capabilities to meet the

USAF requirements.

2. If your company is capable of some but not the entire requirement stated in this RFI, please provide a response that explains the requirements for which you are capable and follow the same rules in the paragraph above.

3. Include a schedule for production and delivery.

4. Provide a Rough Order of Magnitude (ROM) for the acquisition of 20 MARBLES systems and/or

B-52 ASC systems. The ROM Shall include the cost of each component separately (Torso

Harness, Seat Cushion, Back Cushion, Lumbar Pad). Please note: ROM pricing, if available, shall be considered informational and is not considered an offer to buy or an offer to sell and does not bind respondent or the USG into any purchase agreement or contract.

5. Explain how your products will comply with 10 U.S.C. 2533a (“The Berry Amendment”) as it pertains to textiles utilized in your design.

6. Please provide your RFI Reponses to Mr. Colin Cochran on or before 11 OCT 2024. Title email responses in the subject line of the emails as follows: “Response to MARBLES and B-52 ASC

Request for Information # FA8606-24-R-2009.

7. Responses shall include the following information:

• Company/ Institute Name

• Address

• Types of Business (including numbers of employees)

• Point of Contact

• Cage Code

• DUNS Number

• NAICS Code

• Phone Number

• Email Address

• Web page URL

8. All prospective contractors must be registered in the System for Award Management (SAM) database to be awarded a DoD contract. The North American Industry Classification System

(NAICS) code for this requirement, if applicable to the company’s capabilities, should be included in the company’s NAICS code listed in SAM.

9. Please limit your response to no more than 30 pages, to include product sheets, test data, graphs, charts, and answers to the questions above; and identify a representative to support further

Government inquiries and requests for clarification of the information provided, if needed.

Marketing materials are considered an insufficient response to this RFI.

10. Respondents should indicate which portions of their responses are proprietary and mark accordingly. All information received in response to this RFI that is properly marked as

“proprietary” will be handled accordingly. Proprietary information must be clearly marked on the outside container and on the materials inside. The Government shall not be liable for, or suffer any consequential damages, for any proprietary information not properly identified.

11. Verbal questions will NOT be accepted. All questions will be answered via email to all interested parties; except as provided above. Additionally, questions must NOT contain trade secrets or classified information. The Government reserves the right to not address questions received after

11 OCT 2024.

Questions:

1. Responses to questions from interested parties will be promptly answered via email, unless some release of proprietary information is involved, or the answer addresses a question specific to a company or that company’s response. Post submittal, one-on-one information sessions with respondents are not contemplated; however, they may be offered to responders to clarify the

Government’s understanding of their submittal, the capability ramifications, or to discuss their business approach. Information feedback sessions may be offered to respondents after the RFI assessments are completed.

2. Points of Contact (POC) for this RFI:

Colin Cochran, Contracting Specialist colin.cochran@us.af.mil

1st Lieutenant Dongli Ye, Program Manager dongli.ye@us.af.mil

Contracting Office Address:

Bldg. 12

1981 Monohan Way

Wright-Patterson AFB, Ohio 45433 mailto:colin.cochran@us.af.mil mailto:dongli.ye@us.af.mil

DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited.

Number: CSB-002A

Date: 7 Mar 2019

Subject: USAF Revision of MIL-HDBK-516C section 9.1.1Escape system safety compatibility criteria standard; supporting data and legacy criteria.

References:

Parr, Jeffrey, “A Method to Develop Neck Injury Criteria to Aid Design and Test of Escape Systems Incorporating Helmet Mounted Displays,” AFIT/DS/ENV/14-01.

Rowson, Steven and Duma, Stefan, “Brain Injury Prediction: Assessing the Combined Probability of Concussion Using Linear and Rotational Head Acceleration,” Annals of Biomedical Engineering, Vol. 41, No.5, May 2013.

Gennarelli, Thomas & Wodzin, Elaine, editors, “Abbreviated Injury Scale 2005, Updated 2008,” Association for the Advancement of Automotive Medicine, Oct 2008.

Joint Service Specification Guide, 2010-11, Crew Systems Emergency Egress Handbook, 30 Oct 1998.

Joint Service Specification Guide, 2010-12, Deployable Aerodynamic Decelerator Handbook, 30 Oct 1998.

Crew Systems Bulletin

AFLCMC/EZFC

Bldg 28, 2145 Monhan Way

WPAFB, OH 45433-7017

Phone 937-656-9683

Revision History

Rev. Change details Date -- Initial release with initial number: EZFC-CSB-16-001 28 Nov 2016 A Updating bulletin numbering system 7 Mar 2019

Background:

Airworthiness change notice 516CN-5 implements updates to the Air Force standard for airworthiness criteria in section 9.1.1 of MIL-HDBK-516. In order to accommodate the format of MIL-HDBK-516 and associated templates much of the supporting data for the new criteria could not be included directly in the document. Consequently it is being presented in this bulletin, below, in section 1.

In addition, there was a desire to present legacy criteria for instances where minor modifications may be made to legacy systems, which do not justify the necessity to meet the new criteria. This legacy data is also presented below in section 2. Appendix A of this document has also been added to provide some context and rationale for the new criteria; as a means of documenting the intent of the update. Appendix B is intended to present guidance for standard methods of collecting and processing data from escape system tests. Appendix C includes guidance for minimum seat and manikin instrumentation for ejection seat tests.

Appendix D provides information on acceptable manikin configurations for USAF ejection seat tests.

1. Direct supporting data for change notice 516CN-5, MIL-HDBK-516 revision of Air Force section 9.1.1 Escape system safety compatibility, current airworthiness standard.

1.1 Dynamic Response Index Z axis (DRI/DRZ) Calculation: The DRI is representative of the maximum dynamic compression of the vertebral column of the human body. In physical terms, the human body is described mathematically in terms of an analogous, lumped parameter mechanical model consisting of a mass, spring, and damper. DRI was originally developed for catapult phase only; given the acceleration vector is parallel to the spinal column; within 5o of the z-axis. DRI terms have also been developed for the x-axis (DRX) and y-axis (DRY) which can be combined with the original z-axis term (DRZ) to describe acceleration effects on the human body from all axes after the ejection seat has separated from the aircraft (see Multi-axis Dynamic Response Criterion (MDRC) below). The compression of the human body along an axis is captured by the following second order differential equation:

Where

Displacement of the occupant’s body with respect to the critical point

Occupant’s relative velocity with respect to the critical point

Occupant’s acceleration in an inertial frame

Damping coefficient ratio of the dynamic system

Undamped natural frequency of the dynamic system

Measured acceleration along the pertinent axis of the seat at the critical point

Note. For DRZ and MDRC calculations, measured gz accelerations shall include 1 ‘g’ for gravity.

Critical Point definition: Prior to seat/occupant separation, MDRC and DR are calculated from seat accelerations acting into the Critical Point. The coordinate system and the dimensions that define the location of the Critical Point are given in figure 1.1. Since placement of an accelerometer at the Critical Point is not practical, the seat sensors shall be arranged as follows: the primary seat sensor array consisting of a triaxial accelerometer shall be located on the seat pan and as near to the base of the occupant's spine as possible so that the Z-axis of the sensor(s) is parallel to the seat back tangent plane. The z-axis acceleration shall be used to calculate the DRZ. An additional triaxial accelerometer with the Z-axis of the sensor(s) parallel to the seat back tangent plane shall be mounted on the centerline of the seat back, approximately 46.2 cm (18.2") up from the lower seat reference point. The X and Y accelerations from this accelerometer shall be used to calculate the DRX and DRY, respectively. After seat/occupant separation, MDRC and DR are calculated from lumbar z axis accelerations acting into the base of the spine with the z axis aligned along the spine and with x and y axis chest accelerations as shown in figure 1.2.

The estimated natural frequency and damping ratio for the Air Force flying population along each axis direction is given in table 1.1 based on axis orientation as shown in figure 1.2.

Axis Direction (rad/s)

Eyeballs Out 60.8 0.04

Eyeballs In 62.8 0.2

Eyeballs Left 58.0 0.09

Eyeballs Right 58.0 0.09

Eyeballs Up 47.1 0.24

Eyeballs Down 52.9 0.224

Table 1.1 Natural Frequency and Damping Ratio Coefficients.

Figure 1.1 Seat coordinate system with critical point.

Figure 1.2 Human coordinate system with lumbar and chest acceleration positions.

The dynamic response for each axis is calculated as follows; where is the acceleration due to gravity:

At the maximum deflection, the DRI is defined as:

1.2 Multi-axis Dynamic Response Criterion (MDRC) calculation: MDRC is defined as:

The dynamic response values computed for each x-, y-, and z-axis component of the acceleration time history (see section 1.1 above for calculation method).

The limit value of the dynamic response for each axis direction; as shown in table 1.2.

Axis Direction Limits (5% Injury Risk)

- X Eyeballs Out

+X Eyeballs In

- Y Eyeballs Left

+Y Eyeballs right

= 17

= 17

- Z Eyeballs Up

+Z Eyeballs Down

= 18

Table 1.2 MDRC Dynamic Response Limits per axis.

Figure 1.3 Maximum allowable MDRC value vs. Ejection Speed.

The MDRC shall be below 1 for speeds up to and including 450 KEAS. While not part of the MIL-HDBK-516 standard as a design goal for speeds in excess of 450 KEAS every effort should be made to maintain the MDRC below the line shown in Figure 1.3

1.3 Probability of concussion calculation: The probability of concussion is defined as:

Where ‘a’ is the observed peak linear acceleration and ‘α’ is the observed peak rotational acceleration as a function of time. Figure 1.4 shows probability of concussion plotted against ‘a’ and ‘α’.

Figure 1.4 Probability of Concussion vs. Rotational and Linear Acceleration.

1.4 Neck injury calculations: Neck injury criteria are based on the Multi-Axial

Neck Injury Criteria (MANIC) and the Neck Moment Index about the x axis

(NMIx). MANIC and NMIx are defined below with individual critical values as shown in table 1.3. The probability of AIS 2 or greater injury corresponding to the MANIC and NMIx values is shown in figure 1.5.

MANIC (identified as MANIC (Gy) by Parr) is defined as:

NMIX is defined as:

Where:

Fx = observed x direction shear loading Fxcrit = critical intercept value for x direction shear loading Fy = observed y direction shear loading Fycrit = critical intercept value for y direction shear loading Fz = observed axial loading (+Fz = tension, -Fz = compression) Fzcrit = critical intercept value for axial loading (different for tension/compression) Mx = observed moment about the anatomical x axis (side bending) Mxcrit = critical intercept value for side bending

My = observed moment about the anatomical y axis (sagittal plane anterior/posterior bending, +My = flexion, -My = extension) Mycrit = critical intercept value for sagittal plane moments (different for flexion/extension) Mz = observed moment about the anatomical z axis (neck twisting) Mzcrit = critical intercept value for neck twisting

Manikin

Neck Size

Manikin Mass

Human Mass Component Force Component Moment

(lbs) (lbs) (lbs) (N) (in-lbs) (N-m)

Small Female

Hybrid III (for 103-pound manikin)

103 <114

Fxcrit 405 1802

Mxcrit

593 67 Fycrit -Mycrit

(extens) -Fzcrit (comp) 872 3880 Mzcrit +Fzcrit (tens) 964 4287 +Mycrit (flex) 1372 155

125 114- 130.5

Fxcrit

496 2206 Mxcrit

845 95 Fycrit -Mycrit

(extens) -Fzcrit (comp) 1099 4889 Mzcrit +Fzcrit (tens) 1214 5400 +Mycrit (flex) 1939 219

136 130.5-

Fxcrit

522 2322 Mxcrit

912 103 Fycrit -Mycrit

(extens)

Mid Male

Hybrid III (for 136-pound manikin)

-Fzcrit (comp) 1157 5147 Mzcrit +Fzcrit (tens) 1278 5685 +Mycrit (flex) 2094 237

150 143-161

Fxcrit

561 2495 Mxcrit

1016 115 Fycrit -Mycrit

(extens) -Fzcrit (comp) 1243 5529 Mzcrit +Fzcrit (tens) 1373 6107 +Mycrit (flex) 2333 264

172 161-186

Fxcrit

625 2780 Mxcrit

1195 135 Fycrit -Mycrit

(extens) -Fzcrit (comp) 1385 6160 Mzcrit +Fzcrit (tens) 1530 6806 +Mycrit (flex) 2744 310

200 186-210

Fxcrit

683 3038 Mxcrit

1364 154 Fycrit -Mycrit

(extens)

Large Male

Hybrid III (for 200-pound manikin)

-Fzcrit (comp) 1513 6730 Mzcrit +Fzcrit (tens) 1671 7433 +Mycrit (flex) 3133 354

220 210- 232.5

Fxcrit

777 3456 Mxcrit

1584 179 Fycrit -Mycrit

(extens) -Fzcrit (comp) 1673 7440 Mzcrit +Fzcrit (tens) 1847 8216 +Mycrit (flex) 3673 415

245 232.5+

Fxcrit

836 3719 Mxcrit

1850 209 Fycrit -Mycrit

(extens) -Fzcrit (comp) 1853 8243 Mzcrit +Fzcrit (tens) 2047 9106 +Mycrit (flex) 4248 480

Table 1.3. MANIC and NMIX upper neck critical values based on body mass.

Figure 1.5 Probability of neck injury vs. MANIC and NMIX values.

As plotted above in figure 1.5, the probability of AIS 2+ injury based on the MANIC value is defined by:

As plotted above in figure 1.5, the probability of AIS 2+ injury based on the Neck Moment Index about the x-axis (NMIX) value is defined by:

1.5 Stability and Center of Gravity Envelope.

1.5.1 Pitch Stability for escape systems that will be used where the head supported mass and center of gravity location is outside the range for the standard head listed in table 1.5A while wearing the appropriate sized HGU-55P helmet, high speed visor, combat edge kit, appropriate sized MBU-20P oxygen mask, 3 inches of O2 hose and communications cord. Seat stability will be maintained to align the neutral axis direction of the aerodynamic deceleration parallel to the main rocket thrust line at low speeds (where rocket thrust is the predominant force and drogues may not be deployed long enough to be effective) or the eyeballs-out (eyeballs-in for backward facing seats) direction at higher speeds (where free-stream velocity is the predominant force); and limit excursions about the neutral axis to +/- 20O in the pitch plane and positively damped at all ejection speeds from seat aircraft separation through sustainer rocket burn out. Positively damped means any oscillations caused by the excursions are bounded and eventually return to zero.

Manikin Head Weight (lbs) Cgx (inches) Cgy (Inches)

SF-74A 7.4 0.71 2.33

SF-81 8.1 0.71 1.96

Small Adam 8.4 0.29 1.92

Large ADAM 8.8 0.22 1.91

LM-110 11.0 0.74 1.84

Table 1.5A. Manikin Head weights and Gg location relative to the Occipital Condyle

1.5.2 Yaw stability. Limit excursions +/- 20o in the yaw plane and positively damped at speeds above 250 KEAS. Positively damped means any oscillations caused by the excursions are bounded and eventually return to zero.

1.5.3 Historical data and analysis has shown that controlling the CG envelope is critical to meeting the injury and stability criteria. As a design goal the CG envelope shown in Figure 1.6B illustrates the tolerance about the Center of Gravity (CG) positions for the combined seat/aircrew combination.

Figure 1.6b CG Envelope for one piece seat and movable seat bucket.

1.5.4 Parachute Deployment. The ejection seat-aircrew combination should rotate beyond 90 degrees aft from parachute deployment through parachute opening shock. This ensures that the aircrew is in optimal alignment for the opening shock.

2. Legacy airworthiness criteria for MIL-HDBK-516 section 9.1.1 Escape system safety compatibility standard.

For legacy in-flight escape systems that are not receiving a major upgrade or replacement, legacy requirements will apply per table 2.1.

Parameter Class A: Pre-1970 aircraft & seats

Class B: 1970- 2000 aircraft & seats

Class C: aircraft & seats from 2000-release of this bulletin

Catapult Accelerations

Paragraphs 2.1.1, 2.1.2, 2.1.3, 2.1.4, 2.1.5

Paragraphs 2.1.1, 2.1.2, 2.1.3, 2.1.4, 2.1.5

Paragraphs 2.1.1, 2.1.2, 2.1.3, 2.1.4, 2.1.5

Free-flight/drogue phase accelerations

Paragraph 2.2.1 Paragraph 2.2.2 Paragraph 2.2.3

Head accelerations

Paragraph 2.3 Paragraph 2.3 Paragraph 2.3

Parachute accelerations

Paragraph 2.4 Paragraph 2.4 Paragraph 2.4

Parachute descent rate

Paragraph 2.5.1 Paragraph 2.5.1 Paragraph 2.5.2

Stability Paragraph 2.6.1 Paragraph 2.6.2 Paragraph 2.6.2

Limb Flail Paragraph 2.7.1 Paragraph 2.7.1 Paragraph 2.7.1

Neck Injury Paragraph 2.8.1 Paragraph 2.8.2 Paragraph 2.8.3

Escape Capability Paragraph 2.9.1 Paragraph 2.9.2 Paragraph 2.9.2

Table 1. Legacy system requirements matrix.

2.1 Accelerations: Catapult phase.

2.1.1 The acceleration imposed on the seat occupant in the +GZ direction (parallel to the spinal column) by the ejection catapult should be limited in terms of Dynamic Response Index Z axis (DRZ) values for the z-axis, DRZ, calculated according to the method described below. The following DRIz limits are for specific catapult pre-ignition temperature and ejected weight representing the ejection seat, personal equipment, and human body weight representative of the crew member population anthropometric range. In addition the following limits are based on a configuration which includes the head rest not more than one inch in front of the seat back tangent line, the seat back tangent line no more than 5o offset from the catapult thrust vector, and standard USAF torso harness with a chest strap and lap belt restraint (or equivalent restraint as determined by 711th HPW).

2.1.2 For Class A, B and C systems ensure the mean seat pan acceleration time history generated in system level ejection sled or in-flight tests at test ambient conditions, does not yield a DRZ value in excess of 18.

2.1.3 For Class A, B and C systems ensure the mean seat pan acceleration time history generated in controlled component testing at a pre-ignition temperature of

70 °F does not yield a DRZ value in excess of 18.0 (5% risk of Abbreviated Injury Scale (AIS) 2 injury) with an allowable standard deviation of 1.0.

2.1.4 For Class A, B and C systems ensure the mean seat pan acceleration time history generated in controlled component testing at a pre-ignition temperature of

165 °F does not yield a DRZ value in excess of 22.0 with an allowable standard deviation of 1.0.

2.1.5 For systems that are inconsistent with the above configuration i.e. head rest more than one inch forward of back tangent line, seat back tangent line more than 5o offset from catapult thrust vector and other harness systems, the DRZ values for all pre-ignition temperatures are reduced by 2 in order to compensate for the differences.

See section 1.1 for DRI Calculation method.

2.2 Accelerations: Free-flight and drogue phase (seat/aircraft separation to seat/aircrew separation). The MDRC is a method used to evaluate injury risk due to accelerations in all axis during the free-flight/drogue-flight phase of an ejection. See section 1.2 for MDRC calculation.

2.2.1 For Class A systems, MDRC is not applicable.

2.2.2 For Class B systems, all accelerations shall be limited to meet a MDRC value not to exceed 1.0 (5% risk of AIS 2 injury) up to 350 KEAS and may increase linearly, over 350 KEAS, not to exceed 2.0 at 600 KEAS (see figure

2.1).

Figure 2.1 Maximum allowable MDRC value vs. Ejection Speed.

2.2.3 For legacy Class C systems, MDRC limit of 1.0 is applicable up to 450

KEAS and may increase linearly, over 450 KEAS, not to exceed 1.7 at 600 KEAS

(see figure 2.1).

2.3. Accelerations: Head Injury, all phases. For Class A, B, and C systems head acceleration criteria will be in accordance with the program contractual requirements.

2.4. Accelerations: Recovery parachute deployment/inflation phase. For all

Cases A, B and C, the maximum resultant deceleration/stabilization recovery parachute deployment and inflation loads experienced by the aircrew during escape do not exceed the following maximum resultant chest accelerations.

No more than 15 G (vector sum) if the direction of force applied to the body is random and unpredictable as in a typical manual bailout or crew mounted parachute system.

No more than 25 G (vector sum) if the system is controlled so the force is applied while the body is in an optimum position (inertial resultant in +z to −x direction or “eyeballs out” to “eyeballs down.”)

2.5. Descent rate: Recovery parachute descent/steady state phase.

2.5.1 For legacy Class A and B systems average recovery parachute descent rates do not exceed vertical velocity of 25 ft/sec for 300 pound suspended weight at standard day SL conditions.

2.5.2 For legacy Class C systems average recovery parachute descent rates do not exceed vertical velocity of 24 ft/sec for 337 pounds suspended weight at standard day SL conditions.

2.6. Stability: Free-flight and drogue phase (seat/aircraft separation to seat/aircrew separation).

2.6.1 Seat stability criteria are not applicable to Class A systems

2.6.2 For Class B and C systems, seat stability will be maintained to align the neutral axis direction of the aerodynamic deceleration parallel to the main rocket thrust line at low speeds (where rocket thrust is the predominant force and drogues may not be deployed long enough to be effective) or the eyeballs-out

(eyeballs-in for backward facing seats) direction at higher speeds (where free-stream velocity is the predominant force); and limit excursions about the neutral axis to +/- 20O in the pitch plane and be positively damped at all ejection speeds and +/- 20o in the yaw plane at speeds above 250 KEAS.

2.7. Limb Flail: Windblast, free-flight and drogue phases (seat immersion into airflow to seat/aircrew separation).

2.7.1 Aircraft capable of speeds above 300 KEAS must incorporate limb restraints (arm & leg) to prevent limb flail. Legacy data indicates probability of flail injuries increases with airspeed and is approximately 5% probability at 300

KEAS. Leg restraints should prevent movement of the legs laterally beyond the sides of the seat. Arm restraints should prevent movement of arms rearward beyond the seat back tangent line. For class A, B & C systems this criteria is only applicable to those systems which incorporated limb restraints prior to any modification.

2.8. Neck injury criteria: all phases. The neck injury criteria detailed below apply through all phases of the ejection with and without helmet mounted displays such as night vision goggles or joint helmet mounted cueing system.

2.8.1 Neck injury criteria are not applicable to Class A systems.

2.8.2 The following neck injury criteria apply to Class B systems.

The neck injury criteria, Nij, calculated from the following equation intint M M

F F

N yz ij += should not exceed 1.0 for all time during the escape sequence where Fz is the axial load, Fint is the critical intercept load, My is the flexion/extension bending moment, and Mint is the critical intercept moment. The critical intercepts are as given in table 2.2 below.

Manikin Tension (Lb) Compression (Lb)

Flexion (in - Lb)

Extension (in - Lb)

Small Female 755 755 1370 550

Mid-sized Male 1000 1000 2740 1105

Large Male 1220 1220 3670 1470

Table 2.2 Critical intercept values for Nij calculation.

2.8.3 For Class C systems the following neck injury criteria apply up to 450 KEAS. Above 450 KEAS the Large Male Hybrid III Type Manikin limits apply to all manikins and weight ranges.

The maximum acceptable neck tension (lifting force) limits measured at the occipital condyles (C0-C1, upper neck) and cervical vertebrae (C7-T1, lower neck) are defined in table 2.3 (use linear interpolation for intermediate values in force and time duration). These limits represent the maximum allowable load that can be sustained for a given duration.

Small Female Hybrid III Type Manikin (103 to 118 lbs)

Mid-Size Male Hybrid III Type Manikin

Large Male Hybrid III Type Manikin (200 to 245 lbs)

Duration (ms)

Tension at C0-C1 & C7-T1

(lbs)

Duration (ms)

Tension at C0-C1 & C7-T1

(lbs)

Duration (ms)

Tension at C0-C1 & C7-T1

(lbs)

5 414 5 618 5 761 31 414 35 618 37 761 40 200 45 320 48 450 80 200 80 320 80 450

Table 2.3 Class C Neck Tension Force and Duration Limits for a Given Occupant Size.

Neck Compression and Shear Force Limits

The maximum acceptable cervical compression and shear force limits are defined in table 2.4 (use linear interpolation for intermediate values in force and time duration).

Small Female Hybrid III Type Manikin (103 to 118 lbs)

Mid-Size Male Hybrid III Type Manikin

Large Male Hybrid III Type Manikin (200 to 245 lbs)

Duration (ms)

Compression at C0-C1 & C7-T1

(lbs)

Duration (ms)

Compression at C0-C1 & C7-T1

(lbs)

Duration (ms)

Compression at C0-C1 & C7-T1

(lbs)

5 519 5 790 5 979 27 200 30 320 32 450 80 200 80 320 80 450

Duration (ms)

Resultant Shear at C0-C1

(lbs)

Duration (ms)

Resultant Shear at C0-C1

(lbs)

Duration (ms)

Resultant Shear at C0-C1

(lbs)

5 405 5 625 5 777 20 225 25 337 28 414 29 225 35 337 39 414 37 165 45 247 50 304 80 165 80 247 80 304

Duration (ms)

Resultant Shear at C7-T1

(lbs)

Duration (ms)

Resultant Shear at C7-T1

(lbs)

Duration (ms)

Resultant Shear at C7-T1

(lbs)

5 810 5 1250 5 1554 20 450 25 674 28 828 29 450 35 674 39 828 37 330 45 494 50 608 80 330 80 494 80 608

Table 2.4 Class C Neck Compression and Shear Force Limits for a Given Occupant Size.

Combined Neck Moment and Load Limits

The maximum combined-cervical-force-and-moment limit, expressed as Neck Injury Criteria (Nij), is 0.5, as measured at the occipital condyles (C0-C1). The maximum Nij as measured at the cervical vertebrae (C7-T1) is 1.5. Nij is not applied for pure tension or compression. Nij is calculated from the following equation:

intint M M

F F

N yz ij += where:

Fz is the axial tension/compression load.

Fint is the critical intercept load (defined in table 2.5).

My is the flexion/extension bending moment.

Mint is the critical intercept moment (defined in table 2.8)

Force or Moment

Small Female Hybrid III Type

Manikin (103 to 118 lbs) intercept load or moment

Mid-Size Male Hybrid III Type

Manikin intercept load or moment

Large Male Hybrid III Type Manikin (200 to 245 lbs) intercept load or moment

Tension (lb) (+Fz) 964 1530 1847 Compression (lb) (-Fz) 872 1385 1673 Flexion (in-lb) (+My) 1372 2744 3673 Extension (in-lb) (-My) 593 1195 1584

Table 2.5 Class C Critical Intercept Values for Nij Calculation at C0-C1 and C7- T1 for a Given Occupant Size.

Neck X and Z Moment Limits

To evaluate neck lateral bending (Mx) and rotation (Mz), the Neck Moment Index (NMI) will be calculated. The maximum allowable NMIx, is 0.5, as measured at the occipital condyles (C0-C1) and 1.5 as measured at the cervical vertebrae (C7-T1). The maximum allowable NMIz, is 0.5, as measured at the occipital condyles (C0-C1) and 1.0 as measured at the cervical vertebrae (C7-T1). NMI is calculated using the following equation:

iLIM i i M

M

NMI =

where:

NMIi is NMIx or NMIz

Mi is Mx or Mz

MiLIM is the Mx or Mz limit (defined in Table 2.6)

Appendix A

Background information on 2016 MIL-HDBK-516 revision of Air Force section 9.1.1 Escape system safety compatibility standard.

The following is provided to document the intent of the USAF update to section

9.1.1 of MIL-HDBK-516, change notice 516CN-5.

Congress has recently provided direction on reducing ejection seat injury risk for the full range of aircrew population. A July 2014 Congressional letter to the Secretary and Chief of Staff of the Air Force stated that new and old ejection seats should meet a 5% chance of injury. In the National Defense Authorization Act (NDAA) for Fiscal Year 2015 congress tasked the DoD IG to evaluate aircraft ejection seat safety when using advanced helmet sensors. The DoD IG recommended that MIL-HDBK-516 be updated to ensure that a 5% risk of major injury was the standard for airworthiness. In response to the Congressional letter and DoD IG the USAF has reviewed the operational ejection data that showed the standard USAF ejection seat was achieving less than 2% spinal injury rate that is lower than the 5% rate required by the 1967 MIL-SPEC that drove the development of the ACES II ejection seat. The USAF has identified recently published research that establishes a new head and neck criterion that can be used to establish a 5% chance of an Abbreviated Injury Scale (AIS) 2 neck injury.

(The AIS was developed by what is now the Association for the Advancement of Automotive Medicine to fill the need for a standardized system for classifying type and severity of injuries resulting from vehicular crashes. The AIS was adopted as the standard for crash investigation teams funded by the US Department of Transportation as well as many academic and industry research organizations in the US and internationally. It therefore provides a widely accepted standard of injury classification with which to correlate with injury probabilities.)

The changes to section 9.1.1 of MIL-HDBK-516 are intended to implement the Congressional request and the findings of the DoD IG for new systems and upgrades to the greatest extent allowed by current technology. The proposed criteria establish a 5% or less (in the case of spinal injury) probability of AIS 2 injury for each major phase of an ejection event.

The injury criteria used by the USAF to determine the airworthiness for escape systems has not been updated since MIL-HDBK-516 was initially issued. The criteria as identified were established in 1967 and reflected the requirement for a 5% chance of a major, comparable to AIS 2, spinal injury or other injury caused by seat accelerations. In the late 1990’s the government expanded the aircrew population to include females and larger males and established head and neck load requirements to account for the use of helmet mounted displays. These changes are intended to account for these newer requirements as well as the Congressional and DoD IG guidance.

Existing escape system performance and injury criteria have not always been applied correctly. In recent years some criteria have been utilized without all the specific conditions and/constraints under which they were developed and should be applied. In other cases, criteria have been developed without a way to correlate to injury probability. In addition, particularly with respect to neck injury, multiple criteria have been developed which are difficult to interpret and potentially conflicting. This bulletin seeks to correct some of these issues while attempting to meet the Congressional intent noted above.

Dynamic Response Index (DRI) has been in existence for many years; however in more recent applications, the specific conditions for applying the DRI have not always been carried forth. The DRI was developed around a specific seating geometry of headrest position and direction of applied load relative to the seat back as well as traditional USAF seat restraint harness geometry. In order to apply the DRI correctly these constraints must be present in the system. If not, then extensive testing and/or operational data is required in order to show that DRI can be applied to other system configurations. Without this addition data the DRI limit must be reduced to account for non-standard configurations. In addition, while the DRI was designed to reflect a five percent injury risk (as also currently required by Congress) USAF experience over the past 38 years with the ACES II ejection seat have shown that a 2% spinal injury risk due to catapult acceleration has been achieved and this favorable level of performance should be maintained in USAF aircraft for the future.

Multi-axis Dynamic Response Criterion (MDRC) is defined with three different risk levels for a major or incapacitating injury (AIS2). When using the low risk limiting values a MDRC of 1 has been correlated to 0.5% chance of injury. When using the moderate risk limiting values a MDRC of 1 has been correlated to 5.0% chance of injury. When using the high risk limiting values a MDRC of 1 has been correlated to 50% chance of injury. Due to the difficultly in the past of meeting this requirement up through the desired 600 KEAS envelope of an open ejection seat, it has only been applied up to 450 KEAS. There has been no guidance above 450 KEAS; however, based on empirical data and analysis of MDRC with different risk level limits an attempt has been made to provide guidance for limits above 450 KEAS. This may not provide a five percent injury risk above 450 KEAS but at least provides some boundaries at the higher speeds.

Recent research on head injury has noted the importance of rotational acceleration of the brain in addition to linear accelerations typically associated with brain injury. This combined linear and rotational acceleration criteria as related to concussion injury is provided as guidance for head acceleration limits.

Little new information is available on acceleration injury due to parachute opening shock loads. For typical ejection seat testing, instrumented manikins are generally used which allows for an MDRC to be measured based on manikin mounted instrumentation rather than seat mounted. For these applications

MDRC based on…