U.S. GOVERNMENT PUBLISHING OFFICE

WASHINGTON : 

i 

28–971 2019

[H.A.S.C. No. 115–68] 

ADDRESSING PHYSIOLOGICAL EPISODES 

IN FIGHTER, ATTACK, AND 

TRAINING AIRCRAFT 

HEARING 

BEFORE THE

SUBCOMMITTEE ON TACTICAL 

AIR AND LAND FORCES 

OF THE

COMMITTEE ON ARMED SERVICES 

HOUSE OF REPRESENTATIVES 

ONE HUNDRED FIFTEENTH CONGRESS 

SECOND SESSION 

HEARING HELD 

FEBRUARY 6, 2018 
(II) 

SUBCOMMITTEE ON TACTICAL AIR AND LAND FORCES 

MICHAEL R. TURNER, Ohio, Chairman 

FRANK A. LOBIONDO, New Jersey 

PAUL COOK, California, Vice Chair 

SAM GRAVES, Missouri 

MARTHA MCSALLY, Arizona 

STEPHEN KNIGHT, California 

TRENT KELLY, Mississippi 

MATT GAETZ, Florida 

DON BACON, Nebraska 

JIM BANKS, Indiana 

WALTER B. JONES, North Carolina 

ROB BISHOP, Utah 

ROBERT J. WITTMAN, Virginia 

MO BROOKS, Alabama 

NIKI TSONGAS, Massachusetts 

JAMES R. LANGEVIN, Rhode Island 

JIM COOPER, Tennessee 

MARC A. VEASEY, Texas 

RUBEN GALLEGO, Arizona 

JACKY ROSEN, Nevada 

SALUD O. CARBAJAL, California 

ANTHONY G. BROWN, Maryland 

TOM O’HALLERAN, Arizona 

THOMAS R. SUOZZI, New York 

JIMMY PANETTA, California 

JOHN SULLIVAN, Professional Staff Member 

DOUG BUSH, Professional Staff Member 

NEVE SCHADLER, Clerk 
(III) 

C O N T E N T S 

Page 

STATEMENTS PRESENTED BY MEMBERS OF CONGRESS 

Tsongas, Hon. Niki, a Representative from Massachusetts, Ranking Member, 

Subcommittee on Tactical Air and Land Forces ................................................ 3 

Turner, Hon. Michael R., a Representative from Ohio, Chairman, Subcommittee on Tactical Air and Land Forces .................................................................. 1 

WITNESSES 

Cragg, Clinton H., Principal Engineer, NASA Engineering and Safety Center . 4 

Joyner, RDML Sara A., USN, Navy Physiological Events Action Team Lead, 

U.S. Navy .............................................................................................................. 6 

Nowland, Lt Gen Mark C., USAF, Deputy Chief of Staff for Operations, 

U.S. Air Force ....................................................................................................... 8 

APPENDIX 

PREPARED STATEMENTS: 

Cragg, Clinton H. ............................................................................................. 32 

Joyner, RDML Sara A. ..................................................................................... 39 

Nowland, Lt Gen Mark C. ............................................................................... 52 

Turner, Hon. Michael R. .................................................................................. 29 

DOCUMENTS SUBMITTED FOR THE RECORD: 

[There were no Documents submitted.] 

WITNESS RESPONSES TO QUESTIONS ASKED DURING THE HEARING: 

[There were no Questions submitted during the hearing.] 

QUESTIONS SUBMITTED BY MEMBERS POST HEARING: 

Mr. Gaetz .......................................................................................................... 75 

Ms. Tsongas ...................................................................................................... 73 

Mr. Turner ........................................................................................................ 67 

(1) 

ADDRESSING PHYSIOLOGICAL EPISODES IN FIGHTER, 

ATTACK, AND TRAINING AIRCRAFT 

HOUSE OF REPRESENTATIVES, COMMITTEE ON ARMED SERVICES, SUBCOMMITTEE ON TACTICAL AIR AND LAND FORCES, Washington, DC, Tuesday, February 6, 2018. 

The subcommittee met, pursuant to call, at 3:30 p.m., in Room 

2118, Rayburn House Office Building, Hon. Michael R. Turner 

(chairman of the subcommittee) presiding. 

STATEMENT OF HON. MICHAEL R. TURNER, A REPRESENTATIVE FROM OHIO, CHAIRMAN, SUBCOMMITTEE ON TACTICAL AIR AND LAND FORCES 

Mr. TURNER. Everyone, take a seat. We are under the pressure 

of votes. They are going to happen sometime around 4:00, 4:15, so 

we are going to try to make certain we get through everybody’s 

statements and maybe some initial comments. 

So beginning with my opening comments, the subcommittee 

meets today to receive an update on how the Departments of the 

Navy and the Air Force are addressing physiological episodes [PE] 

in tactical and training aircraft. I would like to welcome our distinguished panel of witnesses. We have Mr. Clint Cragg—is that correct? Okay—Principal Engineer from the NASA [National Aeronautics and Space Administration] Engineering and Safety Center 

[NESC]; Rear Admiral Sara Joyner, Physiological Episodes Action 

Team Lead for the U.S. Navy; and Lieutenant General Mark 

Nowland, Air Force Deputy Chief of Staff for Operations. I want to 

thank each of you for your service and for your important testimony today. 

For over 2 years now, this subcommittee has held briefings, hearings, and conducted site visits regarding the occurrences of physiological episodes, or PEs, in tactical and training aircraft. As I stated before, I believe Navy leadership was initially slow to respond 

to this issue that is having a direct effect on overall readiness and 

affecting the confidence of our pilots, as well as their ability to perform their missions. 

Because it is not just that these events are occurring; it is also 

the anxiety that these events occur in succession. As a result of the 

subcommittee’s activity, the National Defense Authorization Act 

[NDAA] for fiscal year [FY] 2017 included legislation that required 

an independent report of the Navy’s efforts to resolve these issues. 

That report was delivered to the subcommittee in mid-December, 

and a copy has been provided to members’ offices. 

According to the report, the Navy was addressing the PE problem as an aircraft problem, not a human problem. We have to ac-
2 

knowledge that physiological episodes happen to people, not aircraft. I was just talking to the Secretary of the Air Force, and the 

human body as a sensor is perhaps different than just our technological sensors and can give us a gap in the information or data 

that we are receiving, but we have to trust those pilots, those 

human responses and reports that we are having of these issues. 

The report also concludes that the F/A–18 systems that support 

human health are ‘‘complex, dynamic, and interactive.’’ As a result, 

the more complex, dynamic, and interactive a system is, the more 

important it is to have a well-coordinated systems approach to 

design and operations. 

Finally, the report notes that the physiological episodes will persist in the F/A–18, and all high-performance aircraft, if there is a 

piecemeal approach to human systems integration. Our witness, 

Mr. Cragg, was the primary author of this report, and he is prepared to provide the subcommittee with a summary of the report’s 

findings and recommendations. 

On September 15th of last year, Ms. Tsongas and I visited the 

Naval Air Station Pax [Patuxent] River to receive briefings on the 

root cause and corrective action processes from members of the 

Navy’s Physiological Episodes Action Team [PEAT]. We spoke with 

engineers and pilots and learned about the Navy’s process to find 

the root cause of these events. We were also briefed on the Navy’s 

attempts to alert and protect the aircrew and monitor the system. 

Additionally, we spoke with engineers at some of the labs who 

are analyzing specific portions of the primary systems that make 

up the Environmental Control System, ECS, and the On-Board Oxygen Generating System, OBOGS. I believe the Navy has taken a 

step in the right direction by establishing a formal action team directly responsible for addressing physiological episodes. The team 

is led by our Navy witness today, Rear Admiral Joyner. 

However, despite these efforts, pilots are continuing to experience physiological episodes, and I am concerned about the increased frequency. For example, since the subcommittee’s last 

event in May of last year, the Navy as well as the Air Force have 

continued to report incidences of PE in aircraft. 

This past summer, the Navy made the decision to ground T–45 

training aircraft due to increasing occurrences of pilots experiencing hypoxia symptoms in the aircraft. The decision was made after 

a significant number of instructor pilots at all three T–45 training 

locations refused to fly the aircraft due to safety concerns with the 

oxygen systems. It is an incident that we were very concerned 

about in this committee that would have to go to the level of the 

pilots themselves intervening and refusing to fly, prior to leadership understanding the need to intervene. 

The Air Force grounded F–35 Joint Strike Fighters [JSF] at Luke 

Air Force Base in June of last year due to oxygen problems, and 

the F–35 fleet has experienced 29 physiological episodes to date. 

In early December of last year, the subcommittee was informed 

that 13 A–10 aircraft at Davis-Monthan Air Force Base have been 

grounded due to problems with the oxygen systems. And just last 

week, the Air Force grounded all T–6 training aircraft at six operating locations due to an increasing rate of unexplained physiological episodes in the T–6 aircraft. 
3 

There is no doubt this remains a complex problem to solve that 

requires a well-coordinated systems approach to include all factors, 

such as the aircraft, the pilot, and the environment. So in closing, 

we need to be reassured that this remains a top priority for the 

Navy and the Air Force and that the two services are coordinating 

efforts and that such a systems approach to solve this problem is 

being taken. 

The increasing frequency of these physiological episodes is having a direct effect on overall readiness, and as such we expect to 

receive your professional assessments on what we as members of 

this subcommittee can do to help you address this critical problem. 

In addition to effects on readiness, this has a direct correlation and 

effect on morale. 

Before we begin with witnesses’ opening statements, I would like 

to turn to my good friend from Massachusetts, Ms. Niki Tsongas, 

for any comments that she may want to make. 

[The prepared statement of Mr. Turner can be found in the Appendix on page 29.] 

STATEMENT OF HON. NIKI TSONGAS, A REPRESENTATIVE 

FROM MASSACHUSETTS, RANKING MEMBER, SUBCOMMITTEE ON TACTICAL AIR AND LAND FORCES 

Ms. TSONGAS. Thank you, Mr. Chairman, and good afternoon to 

our witnesses. It is good to have you here. And I want to thank 

Chairman Turner for holding this hearing and continuing the subcommittee’s focus on this really important issue. 

One of the reasons for today’s hearing is a completion of the independent review of the Navy’s efforts to address persistently high 

rates of physiological episodes experienced by aviators in F/A–18 

aircraft, a critical issue since these episodes can put a pilot’s life 

at risk. 

The review was mandated by the fiscal year 2017 NDAA and 

conducted by the NASA Engineering and Safety Center under the 

leadership of Mr. Clinton Cragg, who is here with us today, and I 

would like to thank you, Mr. Cragg, and your entire team for your 

diligent work on the report. 

I am also pleased that Rear Admiral Joyner is with us today, but 

I must point out that the Navy has decided to move the Admiral 

out of her current position overseeing the service’s response to 

physiological episodes after less than a year in the position. While 

I understand that the Navy is working to find another talented officer to take over the position, I do believe that making the change 

so soon sends an unfortunate message to the entire Navy aviation 

community, including their families. This important issue deserves 

unified leadership and I would urge Navy leadership to prioritize 

continuity in this position moving forward. 

After reviewing the report, it appears its findings and recommendations fall into three broad categories. First, it makes several findings and recommendations related to the, quote, ‘‘human factors’’, 

unquote, underlying the Navy’s physiological episode problem. The 

report states upfront that, quote, ‘‘Physiological episodes happen to 

people, not aircraft’’, unquote. It goes on to point out numerous 

areas where human factors research, data gathering, and testing is 

needed to provide a true end-to-end understanding of the problem. 
4 

I will have several questions on some of the issues raised in the 

report in this area. 

Second, the report points out several specific concerns with the 

design and specifications of the F/A–18 aircraft related to aircrew 

life support. It places particular attention on the aircraft’s oxygen 

generation and cabin pressure systems, raising significant questions regarding both. 

Finally, the report examines internal Navy organizational challenges that may be making it much harder to address the PE issue. 

In particular, the report focuses attention on the need for the 

Navy’s medical community to be more tied into the Navy’s ongoing 

lines of effort. 

And of special concern to me, given what we learned about the 

situation the Navy faced this summer in its T–45 training community, the report also raises concerns about, quote, ‘‘a breakdown of 

trust in leadership within the pilot community,’’ unquote, regarding 

the Navy’s efforts on this issue. 

I know that hundreds of dedicated people in the Navy are working very hard to address this problem. But the report points out 

that we have a long way to go and that in some areas we can do 

much, much better. I am hopeful that the Navy is carefully examining the findings of this report and acting on them as quickly as 

possible and hope to learn more on this front today. 

The other reason for today’s hearing is to get an update from the 

Air Force on its challenges with its own physiological episodes, 

most recently in F–35A, A–10s, and T–6A aircraft fleets. In the 

case of the T–6A, the Air Force’s fleet remains grounded. We need 

to know the full story of what happened and how the Air Force 

plans to stay ahead of this problem moving forward. I look forward 

to today’s testimony and yield back. 

Mr. TURNER. Thank you, Ms. Tsongas. Without objection, all our 

witnesses’ prepared statements will be included in the hearing 

record. 

Mr. Cragg will begin, followed by Admiral Joyner and General 

Nowland. Mr. Cragg. 

STATEMENT OF CLINTON H. CRAGG, PRINCIPAL ENGINEER, 

NASA ENGINEERING AND SAFETY CENTER 

Mr. CRAGG. Chairman Turner, Ranking Member Tsongas, and 

members of the subcommittee, thank you for this opportunity to 

discuss the NASA Engineering and Safety Center’s, or NESC’s, 

independent assessment of the Navy’s efforts to understand and 

mitigate the F/A–18 fleet physiological episodes. 

Mr. TURNER. I am sorry, sir. If I could interrupt you for a second, 

if you could move that microphone to in front of you, because we 

are not hearing you— they are directional. If you could point it at 

you, there you go. Thank you. 

Mr. CRAGG. Too complicated for me. I am honored to be serving 

as the lead for this NESC team. The NESC performs independent 

testing, analysis, and assessments to help address some of NASA’s 

tougher challenges. 

We can draw upon technical experts from all 10 NASA centers, 

from industry, from academia, and other governmental agencies. 
5 

This allows us to bring the country’s best experts to bear on the 

problems and challenges of NASA programs. 

In February 2017, the U.S. Navy’s Naval Air Systems Command 

requested NASA’s assistance in assessing the Navy’s efforts to understand the causes of physiological episodes affecting aircrew on 

their F/A–18 fleet. In March of 2017, the NESC assembled a multidisciplinary team with a broad range of expertise that included 

flight surgeons, life support system experts, engineers, and several 

subject matter experts. 

In the course of this investigation, the team reviewed data from 

a variety of sources, visited multiple manufacturing sites and Navy 

commands, and held numerous discussions with knowledgeable 

personnel. The NESC team’s findings and recommendations are 

based on this data and not an exhaustive review of all F/A–18 documentation. 

To address the complex causes of physiological episodes, the 

NESC team used a multi-systems trends analysis approach and 

formed the following resulting findings. First and foremost, physiological episodes are a human phenomenon. Although the Navy has 

put a significant effort into investigating the physiological episodes, 

the bulk of their efforts to date have been directed at the aircraft, 

rather than human physiology. Centering our investigation on the 

human element revealed new information about the character of 

physiological episodes. 

Second, hypoxia—determined to be the most prevalent cause of 

physiological episodes—is not a condition of insufficient oxygen in 

the breathing gas. It is insufficient delivery of oxygen to tissues of 

the body, importantly, the brain. 

Third, a key reliable On-Board Oxygen Generating System performance is uniform operating conditions, which the F/A–18 design 

and dynamic operating environment rarely provides. 

Fourth, the F/A–18 program has a large amount of aircraft performance data, but a shortage of evidence related to human health 

and performance in an F/A–18 environment. 

Fifth, the F/A–18 systems that support human health are complex, dynamic, and interactive. This requires a well-coordinated 

systems approach to design requirements, interfaces, and operations. 

Finally, an unacceptable number of physiological episodes will 

persist in the F/A–18 program if there continues to be a piecemeal 

approach to the human systems integration. 

The NESC team made the following observations regarding the 

Navy processes. Until recently, the absence of a single leader to coordinate and prioritize the Navy’s physiological episodes efforts resulted in organizational stove-piping and exclusion of key stakeholders. Investigations have been structured as if the physiological 

episodes were isolated events, rather than a series of related 

events. 

Furthermore, troubleshooting efforts used a top-down approach 

that emphasized component-level behaviors instead of evaluating 

the performance of the system as a whole. In this case, the system 

means the aircraft, the pilot, and the environment. 

The NESC team asserts that a dedicated, coordinated, crossorganizational, and cross-discipline program—under the direction 
6 

of a single leader with clearly defined authority—would improve 

the U.S. Navy’s effectiveness in finding and fixing the causes of 

physiological episodes. 

The NESC team has identified a number of near- and long-term 

recommendations. Near-term tasks are focused on gathering key 

evidence about human health and performance and understanding 

hypoxia in the F/A–18 flight environment. Long-term tasks which 

may provide substantial benefit include utilizing a data-driven 

causal analysis effort, updating the F/A–18 to conform to MIL– 

STD–3050 [Military Standard], and developing a systems-level understanding of bleed air management systems. 

In conclusion, and although key data is lacking, the NESC believes that the majority of F/A–18 physiological episodes are a result of hypoxia. This hypoxia, it is believed, is caused by a combination of issues affecting the various stages of oxygen delivery process, including those stages within the human. 

We applaud the Navy’s efforts to gather the necessary data to resolve these issues. The NESC report has provided a conceptual 

framework to view the issue of physiological episodes in a new light 

and offers recommendations that may guide future processes and 

technological improvements. 

I thank you for the opportunity to testify before the subcommittee and look forward to your questions. 

[The prepared statement of Mr. Cragg can be found in the Appendix on page 32.] 

Mr. TURNER. Admiral Joyner. 

STATEMENT OF RDML SARA A. JOYNER, USN, NAVY 

PHYSIOLOGICAL EVENTS ACTION TEAM LEAD, U.S. NAVY 

Admiral JOYNER. Mr. Chairman, Representative Tsongas, and 

distinguished members of the subcommittee, thank you for the opportunity to appear before you today to discuss the Department of 

the Navy’s ongoing efforts to address physiological episodes, or 

PEs, in fighter and attack and training aircraft. 

Addressing PEs remains the Navy’s number one safety priority 

and encompasses naval and Marine Corps aviation communities. 

We have implemented numerous technical and operational measures to mitigate the risk to our aircrew. Utilizing every resource 

available to resolve these issues, the Department of the Navy has 

engaged a broad spectrum of internal and external partners, including subject matter experts from the United States Air Force, 

National Aeronautics and Space Administration, Federal Aviation 

Administration, industry, academia, medical communities, and the 

Navy’s dive communities. In addition, we have established regular 

fleet communication to share all data and progress related to PEs. 

I would like to first focus on the efforts of the Physiological Episodes Action Team, or PEAT. In April 2017, the Chief of Naval Operations directed a comprehensive review of PEs be conducted. As 

a result, the PEAT was formed to serve as a single-source Navy 

and Marine Corps entity which unites both Department of Defense 

[DOD] and non-DOD entities as a cohesive force to combat PEs. 

The PEAT follows three lines of effort: Warn the aircrew, fix the 

machine, protect and prevent. Our efforts rely on understanding of 
7 

an inherently challenging environment encountered at altitude and 

its effects on the human body. 

The PEAT has served to synchronize efforts to resolve physiological episodes between NAVAIR [Naval Air Systems Command], 

Commander Naval Air Forces, Bureau of Medicine and Surgery, 

the Naval Safety Center, our industry partners, and academia. 

Coordinating multiple agencies, the PEAT’s focus is on finding 

the root causes of PEs, correcting deficiencies that they are identified, and equipping existing agencies with long-term resources to 

address PE issues effectively. 

Additionally, the PEAT is responsible for providing timely information to aircrew and maintainers regarding past PEs, present research, ongoing mitigation efforts, and future plans. Direct fleet engagement has been established where representatives from the 

PEAT, NAVAIR, and the Naval Safety Center are available for 

frank and direct dialogue with aircrew, providing an open forum 

between warfighters and leadership. 

We provide a response triage reports to aircrew to improve feedback and communication. These efforts combined have made a 

great impact in restoring aircrew confidence in their equipment 

and the efforts to resolve the PE problem. 

Why haven’t we solved the issue yet? Our incredibly talented engineers at NAVAIR have worked diligently to ensure the aircraft 

are operating according to required specifications and that material 

solutions met engineering requirements. As our aircraft capabilities 

have advanced, we have encountered challenges in how to best support the human in the cockpit in an ever more dynamic environment. 

Today, we benefit from oxygen systems that no longer limits prolonged operations. Rather it is limited only by the constraints of 

fuel, ordnance, and human endurance. Routinely operating for 8 

hours or longer on a combat mission, by flying higher, faster, and 

longer, we have come to realize that there are aspects of our operational environment that need to be more fully understood. 

The NASA report was valuable in reminding us that we need to 

consider not just what we were most comfortable with addressing— 

the engineering elements—but also the human performance element of the aviation environment. 

The effects of pressure and breathing gas composition on the 

human body. It became apparent that in order to discover physiological episode root causes, we needed to start with the human, the 

aviator, and the cockpit. The close relationship between our aeromedical specialists and our engineers had atrophied, and we are 

working actively to restore this relationship in combatting PEs. 

Today we acknowledge that there is more we need to learn about 

human physiology in a pressurized environment and incorporate 

that into our engineering design. We are moving forward to close 

our knowledge gap through research and instrumentation on humans in flight and to develop a thorough and holistic understanding of environmental challenges in the flight regime that results in 

PEs. 

I would like to thank Congress for supporting the Navy’s and our 

efforts to address PEs. We were able to combine congressional 

funding with other resources to immediately put into motion re-
8 

search and material solutions to address physiological episodes, as 

well as expedite longer-term solutions. 

We are moving forward in optimizing the cockpit environment 

with measurable improvements, providing our aviators with every 

tactical advantage in a dynamic environment in which they operate. It is appropriate that I appear today with our Air Force partners. Not present today are our international partners who continue to assist us in gathering data and providing solutions to the 

PE issue. 

Right now, the Royal Australian Air Force and the Swiss Air 

Force fly with instrumentation to gather further data in support of 

our efforts. I have no doubt that through our coordinated efforts we 

will be successful in resolving this issue for the U.S. Navy, the Marine Corps, the Air Force, and our international partners. 

Thank you for the opportunity to present our progress today. I 

look forward to your questions. 

[The prepared statement of Admiral Joyner can be found in the 

Appendix on page 39.] 

Mr. TURNER. General Nowland. 

STATEMENT OF LT GEN MARK C. NOWLAND, USAF, DEPUTY 

CHIEF OF STAFF FOR OPERATIONS, U.S. AIR FORCE 

General NOWLAND. Chairman Turner, Ranking Member Tsongas, 

and distinguished members of the subcommittee, thank you for the 

opportunity to provide an update on our physiologic events within 

your United States Air Force. 

Today I will address some of the risk our airmen face defending 

our Nation, as well as multiple initiatives underway to address 

physiological events. Operating high-performance aircraft is fundamental to air superiority. Inherently, the nature of our profession 

means there will always be risk to the human body. It can be 

caused by unforeseen mechanical issues in our increasingly complex aircraft or by overstressing our bodies when we are max performing those aircraft to their combat capability. 

As the Deputy Chief of Staff for Operations, I believe that training our pilots is the critical factor between life and death. Whether 

it is executing the right procedures during in-flight emergency or 

the maneuvers necessary to defeat an adversary in combat, training is paramount. Therefore, we make sure it goes hand-in-hand 

with material solutions when we implement recommendations for 

physiologic events. 

The Air Force tracks and provides historical data on physiological events. And even though the probability that Air Force pilots 

will experience a physiological event remains much less than 1 percent per year, the Air Force takes flight safety very serious. The 

service investigates every incident that may impact our most valuable asset, our people. 

And we are in complete agreement with actually the NASA report. This is really about people, as we have discovered over our 

incidents over time. The Air Force increased the budget of our 

711th Human Performance Wing nearly by $60 million over the 

past 10 years, which goes back to the F–22 incidents we had, because we recognized we needed to look at the human element here. 
9 

This funding has supported multiple research vectors into hypoxia, 

biomechanics, and toxicology studies. 

Additionally, the Air Force was able to add five pilot physicians 

last year. I have Dr. Bill Mueller behind me who is an example of 

those. He is a rated Air Force pilot, but he is also a physician, so 

he flies the airplanes that were actually out there and able to talk 

to the aviators. This unique critical program qualifies aerospace 

physicians to fly the airplane and then care for the airmen. 

We have also made organizational changes to the Headquarters 

Air Force Operations staff. I have appointed a general officer to be 

the singular point of contact for physiologic events. We learned 

from the Navy essentially. Brigadier General Bobbi Doorenbos will 

integrate the flow of information during physiological event investigations. She couldn’t be here today because she has something 

with her family, her father, but she is hand-in-hand with Admiral 

Joyner. 

General Doorenbos provides a single nexus to pass information 

from aircrew to senior leaders and across multiple stakeholders. 

We continuously strive to improve our processes which we share information between multiple agencies and our joint partners during 

these events. The Air Force stood up an investigative team called 

the Characterizing and Optimizing the Physiological Environment 

in Fighters. Typical, we have a five-letter name as opposed to the 

Navy’s four. We call it COPE Fighter. This multiple service interagency team identifies solutions to optimize human performance 

and minimize unexplained physiologic events in our high-performance aircraft. 

But they are not always high-performance aircraft. So I would 

like to provide a quick update on our T–6, which is our primary 

trainer, which is critical to United States Air Force. The trainer 

fleet experienced multiple unexplained physiological events since 

the beginning of 2018. The first one happened at Columbus on the 

19th of January, and I happened to be there on the day when it 

happened. It was an extremely cold day. 

We took an operational pause last Friday after we had multiple 

events across the fleet, to include Sheppard and Vance—and if you 

remember, Vance had had previous events. We did it because we 

needed to think about the safety of our student pilots and the instructors. This pause will remain in effect until we are certain that 

aircraft and procedures ensure flight safety. 

Major General Patrick Doherty, the commander of the 19th Air 

Force and our Air Education and Training Command, and his wing 

leaders are actively meeting in person with T–6 instructors and 

student pilots to discuss the current situation and to listen to their 

concerns. We have learned this from our F–22 Raptor, our F–15, 

and our F–35. Direct interface with the leadership to the pilots is 

critical. 

But it is also critical that they meet with the spouses, because 

we need to ensure the family members that we put safety first and 

to explain what actions we are undertaking to repair and return 

the fleet to flying status. The key is trust. If the aircrew doesn’t 

trust their system, the family doesn’t trust the Air Force, we lose. 

That is why training is critical to this whole as we move forward. 
10 

In our experience, we have studied the OBOGS, the onboard generating systems, and for the most part, we have not really discovered anything that is not working properly. We had some A–10 

issues, which was a maintenance issue. We think we are discovering in the T–6 it is a maintenance issue right now. The system 

and the way the systems work is sound. Maintaining it is the critical factor. 

Your Air Force T–6s have flown 2.1 million hours with a physiological rate of 1.95. That means 1.95 incidents for every 100,000 

hours flown. But in 2018, the rate is soaring. So what is going on? 

That is why we paused to look at it. But we also need to get in 

the training, and we totally agree with the Navy—I mean with the 

NASA. We need to instrument our pilots. We are looking into that 

as we move forward. 

I thank you for the opportunity to provide you an update, and 

I appreciate the opportunity to answer any questions. 

[The prepared statement of General Nowland can be found in the 

Appendix on page 52.] 

Mr. TURNER. General Nowland, I got to tell you, I could not be 

more disappointed by your presentation. I mean, we have hearing 

after hearing after hearing on this, and we have this report in front 

of us, and the report and the presentation that we have is that the 

human factor is not being taken into consideration and your answer is training. 

Now, I got to tell you, what I have in front of me—and I just had 

the Secretary of the Air Force in my office, and she does not agree 

with you. And I am glad, because you didn’t ground your aircraft, 

your T–6 aircraft, just last week because of training. And this is 

a significant issue, and it is not just listen and talk. This is pure 

safety. 

Now, when we first started having hearings on this, the issue 

that individuals who are testifying before us came forth with was 

the difficulty to replicate the conditions in which the physiological 

episode happened. No one ever came to us and tried to blame the 

pilots and say it is just an issue of training. There is something 

wrong with the systems that these pilots are relying on for their 

lives and that we are asking them to rely on. 

Now, I was just telling the Secretary—and I mentioned this in 

the very first hearing that we had on this—I had this issue when 

I was a mayor, and it was with my firefighters and their breathing 

apparatus and equipment. And we, too, could not replicate anything that was happening with their equipment except situation 

after situation they found themselves in where their breathing apparatus was failing. And it had an impact of morale on the entire 

fire department. 

And what I am stunned by is that here I am—and I don’t even 

know how many hearings we have had on this—and I still have 

someone who is representing one of the most important service 

branches for our pilots come and say this is an issue of training 

and listening and we need to talk to spouses. I mean, I have this 

report in front of me, and one of the headlines on this report is ‘‘No 

Physiological Monitoring of the Pilot’s Breathing Air Has Been 

Conducted.’’ This isn’t an issue of talking. 
11 

I mean, the Secretary of the Air Force is concerned that the T– 

6 training aircraft are grounded not because somebody doesn’t have 

training. Now, I realize what they have done in the past, but I realize what they are doing now. And I realize the problem that we 

had in the failure of the leadership in the Navy because we had 

pilots that refused to fly because the leadership of the Navy continued to treat this as if it was not a physiological episode that was 

happening to people, but that it was something that, because they 

were not able to replicate it, didn’t need to be addressed. 

Now, we asked for this report and to move forward with this, because we didn’t feel like we were getting the right answers. But if 

you continue to come before us and say this is just an issue of 

training the pilots, I mean, you know, General, should we start 

doing hearing training where we ask you to come before us and 

then let’s have you hold your breath for a minute during the first 

hearing, and the second hearing we will have you hold your breath 

for the second for 2 minutes during the second hearing? It makes 

no sense. 

Mr. Cragg, give us some sense here. I know the OBOGS system 

has been tested. There are certainly concerns of maintenance. 

There are certainly concerns of where to identify this. But clearly 

something is wrong for these number of pilots to have these incidences and these planes to be grounded versus just we just have 

to train them to understand what happened when the incidents 

happen. 

What should be happening to try to fix this so our planes fly 

again and people can get the training and our pilots have the confidence in their equipment? 

Mr. CRAGG. Well, sir, as we looked at the situation, we tried to 

come up with some hypotheses on what was causing the problems 

with the pilots. And we went through and looked—at least on the 

Navy side, we went through and looked at all the cases and our 

flight surgeons came up with a consensus that over 80 percent of 

those cases were due to hypoxia. 

Then we looked at the systems onboard the aircraft, and they 

have what is called an OBOGS degrade light, which comes on when 

the percentage of oxygen gets below certain values. So what we— 

we did a little further digging and found out that many or most of 

the physiological episodes that occurred happened without this 

OBOGS degrade light on. So in other words, they were getting 

enough proper oxygen in the cockpit. 

And so when we went to look further, what we found was there 

is hardly any information on the human in the cockpit. We don’t 

have the amount of oxygen in his mask, the amount of CO2 [carbon 

dioxide] in his mask, the kind of pressure that you would want to 

know about in the cockpit, the breathing rates, those kind of things 

where we could do some kind of physiological assessment of what 

is happening to the pilot. 

CO 

Now, in our report, you may have noticed we had an oxygen diagram that showed how oxygen was—how we think oxygen is being 

taken away in little certain steps by different circumstances like an 

aircrew vest that is too tight, maybe they didn’t have enough water 

to drink before they went on a flight, some things like that. But 
12 

what we really need is to get a picture of the pilot, and we don’t 

have that yet. 

Mr. TURNER. Do you have any sense that that step is being 

taken? I mean, because as we try to do the data, pulling just off 

of these systems that are producing the oxygen, and being unable 

to replicate it, do you see any steps that are occurring to be able 

to get that data of what the human is experiencing? 

Mr. CRAGG. Absolutely. As a matter of fact, I get a weekly summary from the Navy on what they are doing to assist in the physiological episodes. And the one I got end of last week, they have 

made some remarkable progress on getting those type of instruments in the cockpit that are going to measure just those things 

we talked about. 

Mr. TURNER. What is the data saying? 

Mr. CRAGG. Well, I haven’t seen the data, but what they have is 

they are out testing it with the VX–23, I guess it is, so—I mean, 

it is a heck of a lot further on than it was when we delivered our 

report. 

Mr. TURNER. Admiral, what are you finding? 

Admiral JOYNER. So where we are today is, we went to what was 

easy in T–45. We put in a system that could do cockpit pressure 

and oxygen delivered at the regulator outside of the OBOGS system to the pilot, because we could do that. And when we did that 

on the T–45, we had the discovery that we had a flow problem in 

that aircraft, and that was able to give us that. 

But that was an easier solution than what we are pursuing right 

now. What he is speaking of is something called an AMS—it used 

to be called AMS, now it is called VigilOX—which is an attempt 

to measure breathing gas at the pilot. And we have tried several 

systems so far, and there are a lot of difficulties. It is probably one 

of the most difficult aspects of this problem. We are working closely 

with the Air Force to do this, and we are leveraging a lot of their 

early findings in F–22. 

So we are—these systems come forward. They are not perfect, 

but we have flown three flights now with the VigilOX system. We 

are just starting to collect the data. And it is really early with the 

three flights. Right now we don’t see a lot of problems with the oxygen—— 

Mr. TURNER. I know you can’t tell us anything that is conclusive, 

but are you at least being able to capture something that indicates 

that there is a problem? 

Admiral JOYNER. We are able to capture the information of what 

is being delivered at the pilot level. Right now it will take those 

medical professionals and those researchers for us to better understand the data that is being delivered—because it is not apparent 

from the data that we are seeing what the shortfall would be, but 

it is three flights in, so it is very immature at this point. We are 

taking those steps. Those steps were brought forward by the 711th 

Human Performance Wing, some of their early work with the system, and through NASA prompting and also the oxygen labs at 

NAVAIR, there is a lot of work to make these systems work and 

make the data actually speak to us. 
13 

Mr. TURNER. So speak to us about the F–35. Apparently 29 physiological episodes have occurred. What can we learn from what you 

are doing now? And how does that apply to the F–35? 

Admiral JOYNER. I would say with the F–35, I talk to them constantly. A through C. I am sure the general also is collecting that 

data, as well. They enjoy an airframe that speaks to you more 

clearly than any other airframe we have ever had. So if I take my 

legacy Hornet, you are looking at my 1978 Corvette. If I go to a 

Super Hornet, I am looking at maybe a 2016 Lincoln Navigator. 

And I am in a JSF, I am flying the newest and greatest, and it is 

telling us more data than we have ever had. 

So they are actually accelerating a lot of their learning, and they 

just finished testing their OBOGS system, and they have a good 

understanding of that system. And it was a very positive outcome. 

But obviously we have issues that we have to pull apart that are 

not—we haven’t discovered yet at this point. 

Mr. TURNER. Ms. Tsongas. 

Ms. TSONGAS. Thank you. I would like to talk about the role of 

the medical community, as you have wrestled with these very troubling episodes. And I think one of the—obviously the finding that 

we are all most taken by from the independent report is that this 

is so much about people. 

So I am going to quote again from it, just to sort of restate that. 

So chapter 12 states the following. Quote, ‘‘PEs happen to people, 

not to aircraft. The U.S. Navy is addressing the PE problem as an 

aircraft, not a human problem. Remembering that PEs afflict people and not aircraft may help focus activities on better understanding human systems, human system requirements, and human 

system impacts caused by conditions of flight.’’ 

Later, in Appendix A of the report, it goes further and says, 

quote, ‘‘The naval medical community as a whole has not been involved with attempting to solve the PE issue.’’ From the beginning, 

PEs have been viewed as an engineering issue. And you have even 

referenced that, Admiral Joyner. ‘‘Therefore, a proactive investigative U.S. Navy medicine effort never really got underway,’’ unquote. 

As an example of a lack of U.S. Navy medical involvement, the 

report points out that the decision to deploy hyperbaric chambers 

to treat altitude-induced decompression illness appears to have 

been taken at the operational level. That is to say that it was made 

without any senior-level medical involvement. So, Mr. Cragg, can 

you please elaborate on these statements in the report and what 

you and your team think should be done about it? 

Mr. CRAGG. Well, I think we were clear that the medical community needed to get involved. And I am happy to say that they currently are. One of the flight surgeons on my team participates with 

this meeting of naval medical people that is just now getting 

underway to help support the PE processes that Admiral Joyner 

has started. 

You know, it is unfortunate, but when everybody was saying this 

was an engineering problem, they weren’t asked, and so they didn’t 

participate. 

Ms. TSONGAS. And were you surprised to find that? 
14 

Mr. CRAGG. Yes, we were actually very surprised to find that. 

And—— 

Ms. TSONGAS. So now that we found this to be a real shortcoming, Admiral Joyner, these two findings and this particular example, you know, are obviously quite troubling. And I think most 

members would assume that the Navy’s medical community would 

be tightly integrated in all aspects of addressing the PE issue. 

Those of us here certainly would be. 

So what is the Navy currently planning to do in this area of its 

overall PE response? And is there a plan going forward for U.S. 

Navy medical to be involved and in some way that we can depend 

upon? 

Admiral JOYNER. Yes, ma’am. Part of the standup of the PEAT 

was to bring in the Bureau of Medicine and Surgery underneath 

the PEAT in order to coordinate those efforts better. And that is 

what having a single entity to try to bring this entire fabric together has allowed us. 

So what did we do? We set up something called the Aeromedical 

Scientific Advisory Board, environmental advisory board, and they 

are a group of professionals, both medical, academia, oxygen specialists, our research scientists, some of the ones from Dayton, 

Ohio, toxicology out of our NAMRU [Naval Medical Research Unit] 

Dayton group, that are dedicated to advising us as we move forward on the PE issue. 

We also have an aeromedical team that is immediately involved 

in all the responses on the flight lines and analyzing and making 

sure that we are coming up with clinical practice guidelines that 

are coherent and are tied in well with that research community 

and with our medical community. 

And then on top of that is we have the root cause corrective analysis team who has—one of the members is an operator who has become a flight surgeon, much like the Air Force was talking about, 

General Nowland was talking about, and we have those professionals, as well, involved in the root cause analysis to make sure 

that we don’t lose that human element as we go forward to try to 

find the root cause of the PE. So those are several examples. 

Ms. TSONGAS. Have you found that by engaging the medical community in a more structured way, has it changed your clinical practice guidelines? So, for example, have you revisited the treatment 

you might—the ways in which you dealt with hypoxia or dealt with 

decompression illness? 

Admiral JOYNER. I think it has standardized the response across 

the flight line, and it has energized further research in those areas 

that we are not as knowledgeable as we need to be for what the 

type of treatment should be. We also engage NASA, has been involved in several case reviews for us on some of the difficult issues 

of what the treatment should be. 

So we are extending beyond even within our internal resources 

to external resources like NASA, Duke oxygen specialists, and 

other people that we are bringing onboard to better understand 

this problem. So I think it has increased the scope. It has increased 

our consistency with the clinical practice guidelines. And we know 

that the chambers themselves, it is a do no harm. We know that 

they improve in conditions under those treatments, and we are not 
15 

going to stop treating them effectively until we can find something 

better. But we have a full research community dedicated to finding 

out better ways to treat our aviators at this point. 

Ms. TSONGAS. Thank you, I yield back. 

Mr. TURNER. They have called votes. I think we can get to Mr. 

Kelly and Mr. Langevin, and then we will take a break. Mr. Kelly. 

Mr. KELLY. Thank you, Mr. Chairman and the Ranking Member. 

This is a very important issue. I think most of the people in here 

have either soldiers—I mean, sailors or airmen that are affected, 

airpeople, airwomen. I have Columbus Air Force Base, and, General Nowland, we just talked beforehand. And I know your son just 

graduated from there, so I know that you are personally invested 

in getting this right, because you have got skin in the game. And 

I think that applies to all of us who have served. 

I kind of agree—there is multiple issues. And we haven’t figured 

it out at any level, and we have got to figure this out, what is causing this, whether it is maintenance, whether it is lack of training, 

whether it is the improper use of equipment, whether it is the 

equipment itself. We have been going over this a long time, but it 

is critical that we get it right and that we get it right quickly, but 

it is more important that we get it right. 

What type of—I don’t see any movement in finding the solution, 

and that is very, very difficult. So, I mean, you have got to start 

with seeing what those are. What things do you think or is there 

any indication that we are getting close to finding at least what is 

causing it, whether it is the maintenance of the system, which I 

heard you say, General Nowland—and I think that is important. If 

we don’t maintain the system right and don’t do that, then we get 

those episodes. 

Do either of you—and this would—anybody on the board, do we 

have any idea what may be causing this? 

General NOWLAND. Congressman Kelly, thank you very much. 

And, Chairman Turner and Ranking Member Tsongas, and the distinguished members, if you got the impression from my testimony 

that we are blaming pilots, we are not. We are not. 

When I meant training, I am talking holistic training, exactly 

back to your part. Part of our suspicion with the T–6 is that the 

time change technical order for the On-Board Oxygen Generating 

System does not exist. We are formulating it right now. So we 

never trained our technicians on how to maintain that piece of 

equipment. 

What we found in the F–22s is the equipment that we had—the 

aircrew flight equipment, the life support equipment, we didn’t 

have our crews trained properly to wear the equipment properly, 

and we noticed the valve on the chest was part of the solution. 

Back to the altitude chambers, we have 10 altitude chambers, 

but the altitude chamber that we did training 10 years ago or 20 

years ago is different than what we do today. So it is a holistic 

view of all of it. 

So I think right now our suspicion is that the maintenance of our 

On-Board Oxygen Generating System for our T–6s, after having 

flown them for 2.1 million hours, needs to be repaired. So we believe there is a repair that—but we don’t know that for sure. 
16 

The human physiological episode, we absolutely believe—as I 

said with the NASA—that that—we have got to collect data. We 

have ear cups data that we use in the F–35 that allows us to take 

the blood. One of the things that we found is when we have a physiological episode, we do not have the time quite right, because the 

blood alkalinity changes. So we are putting testing equipment that 

will meet the aircrew right at the airplane to try to get the best 

data that we can get from the pilots in the meantime. 

So to answer your question, sir, we are working multiple solutions. We think it is maintenance on the T–6 right now. 

Mr. KELLY. One other quick question. And this is to both of you. 

Grounding of the T–6 or the T–45 or whatever equipment, we already have a pilot shortage across the board. What impact does 

this have on the training pipeline? And what are we doing to make 

sure that we don’t have a prolonged impact which gets, you know, 

the accordion effect as we go in time? 

General NOWLAND. Sir, General Doherty, the 19th Air Force commander, is working two solution sets. One is trying to get the OnBoard Oxygen Generating System to work properly. The second one 

is an interim solution where we would modify the CRU-60, which 

is what we connect our oxygen mask to, take it off of the onboard 

generating system, use the ambient pressure, and then modify the 

flight profile so that we stay between 6,000 and 7,000 feet on cabin 

pressure, and then we would stop all solos. We would always fly 

our crews dual as we working the simultaneous. We lose 700 sorties a day right now with the T–6 grounding. That will have an effect on our pilot training. 

Admiral JOYNER. For the T–45, we have turned the curve. Our 

rate is maybe one-fifth of what it was at the point where we were 

approaching the grounding, and that is a significant change. We 

assess that we have identified the flow problem in the T–45 as 

being the primary issue. We have taken steps to mitigate it. We 

have long-term steps to solve it. 

For right now, though, we have a training impact that is—we are 

trying to absorb in all different phases of flight through our followon training. We are bringing the Reserves to bear against the 

training problem. We are extending the resources of the contract 

support that we have on the T–45. And we are trying to buffer that 

impact across the system, longer term relying on some of our aviators to operate longer on a volunteer basis at sea in order to try 

to blend this across the system. 

But there are impacts. And you can’t deny those. We are just trying to mitigate them at this point. 

Mr. KELLY. Thank you, Chairman. My time is expired. 

Mr. TURNER. Thank you. Before I get to Mr. Langevin, General, 

thank you for clarifying that. This is our fifth hearing and briefing 

on this. We just sort of expect a progression of shared values on 

issues, and I appreciate your clarifying your language, because 

when we began this, as Mr. Cragg has said, it is not just the 

human value, the pilot value is not being honored. I appreciate you 

making that clarification statement. Because there is at times 

when you have something like this the question of, is it real? And 

this committee certainly believes that what is occurring is real. 

Mr. Langevin. 
17 

Mr. LANGEVIN. Thank you, Mr. Chairman. I want to thank our 

witnesses for being here today. It is a very important issue that we 

need to get to the bottom of. 

I haven’t heard a whole lot that makes clear sense of all this yet, 

except for some of the information I have before me right now, so 

I will put this out there and then ask Mr. Cragg to respond first. 

But the NASA review report states on page 15 that, quote, ‘‘A problem with the breathing gas system as a whole is that the onboard 

oxygen generation system gets fed last. The enormous amounts of 

cooling air required for the avionics and radars (especially on the 

E/A–18G Growlers) means that the ECS [environmental control 

system] controls preferentially direct flow to them’’ instead of the 

OBOGS. 

Then finding 10–7 of the report states that, and I quote, ‘‘Avionics flow has priority over cabin flow in some operational cases . . . 

data from the PE flights has directly demonstrated cases in which 

high avionics flow results in lower than required cabin airflow.’’ 

Finally, observation 10–2 in the report states that, and I quote, 

‘‘The Navy appears to have little insight into elements of the ECS 

control programming logic. Discussions with engineering teams at 

the Patuxent River and fleet support activity North Island suggest 

that the logic programming control sets were not part of the contract deliverable for the F–18 and, therefore, may no longer be documented in any form.’’ 

So if I had to summarize these three statements, it would be that 

the crew’s airflow comes last. But the Navy doesn’t seem to know 

exactly why that is the case. So given the aircraft can’t operate 

without its crew, one would think that the opposite would be true. 

So, Mr. Cragg, to you, would you agree with the overall assessment? And what else would you like to add to what is in the report 

on this subject? 

Mr. CRAGG. Thank you. Yes, I would agree with that statement. 

The Navy does not fully understand the pressure control logic, because as you mentioned, it wasn’t part of the F–18 design that was 

supplied to the Navy by Boeing. 

But this somewhat gets to the theme—one of the themes of our 

report that we think the Navy needs to do some human system integration where they look at all aspects of what is going on with 

the human, what is going on with the environment, and how the 

system of the airplane itself operates. And if they don’t have an 

idea of how the logic control portion of a key component, the environmental control system, that is a deficiency. 

And they need to do that. They need to figure out how that operates so—you know, one, they can troubleshoot the system properly, 

but at the other side, they need to do this human system integration where they put everything together and understanding exactly how your systems operate is key to that. 

Mr. LANGEVIN. Admiral Joyner, I also have several questions for 

the Navy following the statements in the report. First of all, what 

can be done to fix this? Does the Navy have all the technical data 

on the F/A–18 to address this issue? And if airflow to the crew was 

given first priority on the aircraft, how would that affect mission 

systems? And then finally, does the Navy have an effort in place 
18 

with Boeing to address this design issue in the current and new 

F/A–18s? 

Admiral JOYNER. I would say I vary in my opinion and my status 

on the ECS system. The OBOGS is the primary system that is fed. 

And cooling air is not removed from the OBOGS system in order 

to feed it elsewhere. There are instances where if the avionics are 

overheating that it won’t pull it from the OBOGS, it will pull it 

from the cooling for the pilot in order to make sure the avionics 

function. None of us want our avionics to shut down, because it will 

result in an ejection, and that is not something we want to see. 

So overall, I would say that when I look at the ECS system on 

the F/A–18, we need to regulate it better. That is where our emphasis has been. Due to the timing of the legacy system in the 

F/A–18, a lot of what is available on the ECS system is analog. It 

is in vaults and it is stored elsewhere. We have access to those, but 

it is not as simple as looking it up on a system. You have to go 

find that. And we are working directly with Boeing to make sure 

we have access to all the support material we need. 

The engineers at NAVAIR reassure me and have walked me 

through the system to explain to me why they know that the pressure system and how they have tested it, but we realize we want 

to test it further on the OBOGS system, and we are taking advantage of the 711th lab that they have that they are able to do dynamic testing that recreates the flow that is given to that system 

in the OBOGS. So we are going to take advantage of that testing, 

as well, to do dynamic testing, not just point testing. 

Mr. LANGEVIN. Did I understand you, though, that you completely disagree with NASA’s findings that the OBOGS system is 

fed last? 

Admiral JOYNER. My understanding of the system is that 

OBOGS is prioritized first, ECS is second. The third system that 

goes is the avionics cooling, except if it starts to compromise those 

avionics systems. And then we are going to pull heat but not pressure out of the system. The F/A–18 has a lot of pressure, and it 

is—from what I see to date, it is more about regulating that pressure, because we are causing over-pressurization at times within 

that system. And that is an issue that we have to—we are putting 

in eight corrections to the ECS system in order to try to regulate 

that pressure better and try to smooth the flow. 

So we realize that our concentrator, our OBOGS system, could 

have a better system and we are pursuing that, but we don’t necessarily agree that the—how it is prioritized is done incorrectly. 

Mr. TURNER. We are going to have to take a recess. We do have 

votes we have to run to. And I know Mr. Gaetz has questions, and 

we will be returning for those. 

[Recess.] 

Mr. TURNER. Okay, we will call the hearing back to order. Please 

have a seat. Mr. Gallego, your questions, please. 

Mr. GALLEGO. Thank you. My question is about the GGU–12 OnBoard Oxygen Generation System on our F/A–18s. 

At three separate points in the report, NASA advises us of testing and practices for the critical system that seem abnormal. First, 

the report states that the Navy and Boeing have not followed wellknown industry best practices in a system that is critical to the life 
19 

support of our F/A–18 aircrews. Further, it appears that current 

test equipment does not simulate real flight conditions actually encountered by the F/A–18s. 

So if that is true, it could generate false positive results, as we 

are hearing from now, that may conceal underlying problems with 

the system as it operates under real conditions. And third, it appears that some of the underlying design specifications for the 

F/A–18’s oxygen generation system are decades, decades out of date 

and do not reflect the latest scientific knowledge on aircrew breathing demands. 

One of the report’s key recommendations to bring these specifications up to date to conform to standards developed in 2015. So, Mr. 

Cragg, taken together, these examples from the report indicate that 

the breathing system of the F/A–18 has serious problems. Do you 

agree? 

Mr. CRAGG. Yes, sir. 

Mr. GALLEGO. And how would you summarize what these problems are? 

Mr. CRAGG. Well, I would say unfortunately the original OBOGS 

specifications were not put through the human systems integration 

process that would have highlighted the fact that it cannot deliver 

for all conditions, like high-stress portions of the flight. That is why 

a key recommendation of our report is to re-examine the OBOGS 

in light of the human system integration effort. And additionally, 

as you pointed out, some of the testing that is done on the OBOGS 

doesn’t utilize in-flight conditions. But I understand they are getting better and closer to the real thing. 

Mr. GALLEGO. They are getting better and closer to the real 

thing. Is there a time period we understand that this is going to 

be happening? 

Mr. CRAGG. I think you have got to ask the Navy that, sir. 

Mr. GALLEGO. Lieutenant General Nowland, while you are not 

Navy, do you have anything to add to Mr. Cragg’s answer? 

General NOWLAND. On the F/A–18, no, sir, I do not. 

Mr. GALLEGO. Okay. I think many of us are a little anxious to 

see some form of conclusion or time period, especially involving the 

lives of our service members. I yield back. 

Mr. Chairman, I yield back. 

Mr. TURNER. Mr. Carbajal. 

Mr. CARBAJAL. Thank you, Mr. Chairman. Thank you all for your 

service and for addressing us today. 

The report makes two statements regarding leadership and communications within the naval aviation community that I want to 

touch on. 

First, in finding 10–29, it states that, quote, ‘‘There has been a 

breakdown of trust in leadership within the pilot community’’ and 

that ‘‘one notable area leading to a lack of trust in leadership is 

the completion of Parts A/B/C of the Physiologic Episode report. 

Once these questionnaires are completed, they disappear through 

the ‘system,’ only to be examined months later. None of the pilots 

interviewed ever received official word as to the cause of the incident or the mitigation the U.S. Navy would be taking to reduce the 

likelihood of a repeated event.’’ 
20 

Second, with regard to feedback from aviators, the report observation 10–20 points out that, quote, ‘‘The Navy has not conducted 

a fleet wide survey of their F/A–18 air crew to understand the PE 

problem from the human perspective, where these events actually 

occur.’’ 

Taken together, it appears that the communication issue noted 

in the Navy’s own comprehensive review conducted earlier this 

year remains a problem. 

Rear Admiral Joyner, what is the Navy doing to get feedback on 

PE event investigations back to the crew members that experience 

them? 

Admiral JOYNER. Yes, sir. What we do right now is we have a 

quick look that we are doing. We start in T–45s, where we try to 

come back at the 48-hour point, and we brief out our quick look response of what we are receiving from the Parts A, B and C, and 

information that we receive from the aircraft itself. And we present 

that to the aircrew. Approximately 30 days later, we come back 

with a full report, which outlines what we found on the aircraft as 

far as any system failures, any additional information we were able 

to derive from the data sets. 

So in F/A–18, we are using Slam Stick data, which tests the 

pressure inside the cockpit. We are getting the OBOGS information 

for any type of malfunctions we are able to find. We also have a 

quick response force that falls in on the aircraft. And rather than 

breaking the system, as we have historically, we holistically analyze a system with a team on station that includes a medical professionals. It includes engineers. A Boeing rep [representative] is 

also onboard. And the pilots are also involved with the pilot maintenance and the aviation physiology, the aeromedical safety officer, 

all fall in on the aircraft to do this analysis and try to figure out 

root cause for each of the events. 

That is all communicated back to the pilots. Part of that communication plan is also what we call the PE road show, which is—I 

just returned from Japan doing one out there, both Atsugi and 

Iwakuni, and we addressed the pilots directly on what we are finding with their aircraft, different trends. We are getting a health 

monitoring system up online that basically shows the prognostic 

health of their airframes by BUNO [bureau number], and we are 

showing them on their aircraft what we are seeing with the data. 

So the feedback loop has been strengthened, and we are making 

sure that we are getting that back down to the deckplates, to the 

aviators, site by site. 

The second part is the survey. We just completed the survey last 

Friday. We did get over 500 responses out of our aviation community, but we also did maintainers, as well. It was a large response. 

We got about 22 percent of aviators and maintainers responded to 

the survey. And that survey is designed to go ahead and solicit that 

feedback and get information about different things that have impacted the pilots and how they are operating. 

So we did take both of those onboard, and we did move forward 

on them quite regularly. And then we also have the weekly newsletters and engagements that we do with the fleet. I go site to site. 

Mr. CARBAJAL. And was this done, this survey of the F/A–18 

community, as well? 
21 

Admiral JOYNER. Yes, sir, that was F/A–18 and T–45. 

Mr. CARBAJAL. Great. May I ask how long this feedback loop has 

been in place? 

Admiral JOYNER. The T–45 feedback loop has been in place for 

roughly I think 3 months. When we stood it up and went back to 

flying, back in September timeframe, we realized that we needed 

to push that information down. And so in September, the T–45 led 

the way, and now we have brought that onboard with F/A–18 and 

we started that roughly November, December timeframe. 

Mr. CARBAJAL. Great. Thank you very much, Mr. Chair. I yield 

back. 

Mr. TURNER. Mr. Panetta. 

Ms. Tsongas. 

Ms. TSONGAS. Thank you all for being here. I am sorry for the 

break, but appreciate your patience. Admiral Joyner, I just have a 

couple of quick questions, really only take a yes or no answer, or 

a maybe if it is not clear that it is one or the other. 

The report states in finding 10–20 that there has been no definable effort to use the OBOGS laboratory at the 711th Wing at 

Wright-Patterson Air Force Base to assess effects on OBOGS output gas. Is there currently a plan in place to conduct this testing? 

Mr. TURNER. I was going to ask that, but I felt like I had a conflict, so thank you for asking that. I did not ask her to ask that, 

but that is important. That is in the report, and that is a question. 

Admiral JOYNER. Yes, ma’am. We are intending to use the 711th 

Dynamic Testing Lab that they have on site. 

Ms. TSONGAS. It is an important resource, and it is a shame it 

took this study to lead to that. Does the Navy intend to issue a request for proposal in the near future for a new On-Board Oxygen 

Generation System for the F/A–18? 

Admiral JOYNER. Yes, ma’am. 

Ms. TSONGAS. Does the Navy intend to develop and install a new 

cabin air pressure monitoring and alerting system for the F/A–18? 

Admiral JOYNER. Yes, ma’am. 

Ms. TSONGAS. Does the Navy intend to design and replace the 

F/A–18’s cabin pressure regulator valves? 

Admiral JOYNER. Yes, ma’am. 

Ms. TSONGAS. Is the Navy doing—— 

Admiral JOYNER. We are looking into a suitable replacement for 

that. We have gone through to repair them and to make sure that 

the maintenance, when they come back out to the fleet, is accurate. 

We are looking at a couple of different options for that valve, but 

right now we have concerns about some of the solutions we have 

been offered. So I wanted to clarify that. 

Ms. TSONGAS. Okay. Is the Navy doing upgrades to the ECS software on F/A–18s and EA–18Gs to deal with icing in the ECSrelated water lines? 

Admiral JOYNER. Yes, ma’am. 

Ms. TSONGAS. And is the Navy planning to install an automatic 

backup oxygen system in the T–45? 

Admiral JOYNER. Yes, ma’am. 

Ms. TSONGAS. Is it planning to do so for F/A–18s? 

Admiral JOYNER. It is not at this time. 

Ms. TSONGAS. Thank you. 
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Mr. TURNER. Admiral, help us. We have had a total of five now 

hearings and briefings. Ms. Tsongas and I both traveled to you and 

have received briefings on this. We asked for this report, and, Mr. 

Cragg, thank you so much for the detailed information that is in 

this, and this is very, very helpful, of, unfortunately, things that 

aren’t happening after things that aren’t happening after things 

that aren’t happening. 

This has got to be fixed. This has got to stop. And I don’t have 

confidence that we are getting nearer to that. I believe that there 

are a number of things that are being done and a number of things 

that are not being done that are now being done because the report 

said to do them. 

But this would seem to me to be something that needs to be done 

quickly and expeditiously and that this should not be a research 

project. This should be a fix-it project. Help me get some sense that 

we have in place things that are going to do that, knowing that 

this started with our having an understanding that pilots had to 

revolt and say, ‘‘I won’t fly’’ because the chain of command wasn’t 

even recognizing their complaints and their incidences, you know, 

all the way to there is still a sense of morale of lives are at risk. 

Help us get a sense that the work that we are doing and the 

work that you are doing is going to result in something. 

Admiral JOYNER. Right now, T–45s are fully operational. They 

operate every day. We have over 27,000 flight hours. We have had 

six events in those aircraft, all mild in nature, one of which was 

a system failure that was identified by the system. 

So we have turned the corner on T–45. We have long-term corrections in place, design changes to the aircraft to fully address it, 

so we are not declaring victory. We have an RCCA, root cause corrective analysis, team that goes line by line, starting with the 

human, ending with the human, trying to find root cause for both 

the T–45 and the F/A–18. 

Industry is involved. Aeromedical is involved. NASA helps consult and keep us on track so that we don’t lose sight of things that 

may be falling out. We have a long-term goal of adding a robust 

human systems integration effort on par with our aircraft design 

requirements and engineering force. So we are looking to fully integrate them within our efforts. 

On F/A–18, we are turning the corner. We see now that we are 

able to influence the pressure response on the aircraft. We have 

been able to make noticeable and observable, measurable changes 

to the F/A–18, which are resulting in a better, more stable ECS 

system. There are long-term design changes in place to ensure that 

we further stabilize that system and we have an OBOGS concentrator that we are looking for a request for proposal. 

We are open to added things that are found along the way in 

order to make sure that we are not missing anything. That root 

cause effort is a longer-term effort that will lead us—the medical 

force outcomes will take more time. Those are fully funded through 

the FYDP [Future Year Defense Program] type of efforts to fully 

define pressure and oxygen requirements for pilots. We are working with the Air Force actively, and we are pursuing all those answers long term. 
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I don’t—every day I ask myself, what else could we be doing that 

we are not doing? I turn to NASA and I ask those questions. I work 

with the Air Force. And we make sure in academia, as well. And 

we want to make sure that we are not missing a single thing, and 

we have gotten your assistance, as well, which is helping us do 

those efforts. 

So all I can tell you is, my effort doesn’t stop. I will have somebody who will relieve me in this effort, and we won’t stop until we 

resolve it. 

Ms. TSONGAS. I want to thank Mr. Cragg for this very important 

study that I think has helped create a path forward. And I appreciate, Admiral Joyner, the seriousness of purpose you have brought 

to this effort. Again, as I said in my opening remarks, I am very 

concerned that you are being rotated out in less than a year into 

this effort and remain very hopeful that somebody will be put in 

your place who can stick with it a little longer, because we know 

change does lead to setbacks. And we can’t afford to lose any more 

time. 

And just wanted to say, as we are here, as we sit here today, new F/A–18s are rolling off the production line at a cost of about $69 

million per aircraft. At some point, paying $69 million for an aircraft we know has serious problems with its life support system 

has to be questioned. So I am not calling for stopping production, 

but it seems clear that the Navy and Boeing need to work together 

and come up with improvements to the F/A–18 that make them 

safer for our brave men and women in the military to operate, because we know it puts their lives at risk, and to make sure every 

single new F/A–18 has those improvements built in from day one 

and we are not back here a good number of years hence revisiting 

these same problems yet again. 

Thank you, and I yield back. 

Mr. TURNER. Thank you. Mr. Cragg, many times this committee 

authorizes a request for a report to be done. You and NASA have 

outdone yourselves. This was a phenomenal and excellent report. 

It is great to see that work product translated from our request. 

And thank you for the dedication of which you approached this. 

Appreciate all of your efforts for this. I hope as we get to our— 

what will have to be a sixth hearing and/or briefing on this, that 

we have a greater sense—although, Admiral, I appreciated your 

closing comments of things that you are accomplishing—a greater 

sense that this is being advanced in a way that hopefully the committee can feel as if it is being done in a way that our oversight 

is no longer necessary and these can be just incidences that go into 

reports instead of incidences that in the aggregate require congressional action. 

Thanks. With that, we will adjourn. 

[Whereupon, at 5:40 p.m., the subcommittee was adjourned.] 

A P P E N D I X 

FEBRUARY 6, 2018 

PREPARED STATEMENTS SUBMITTED FOR THE RECORD 

FEBRUARY 6, 2018 

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QUESTIONS SUBMITTED BY MEMBERS POST HEARING 

FEBRUARY 6, 2018 

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QUESTIONS SUBMITTED BY MR. TURNER 

Mr. TURNER. a) By centering your investigation on the human element, what new 

information was revealed? 

b) What were the shortages of evidence related to human health in an F/A–18 environment that you encountered? 

Mr. CRAGG. 4a: 1. NASA flight surgeons, reviewing pertinent Physiological Episode (PE) Medical information as a whole instead of just individual cases, determined that > 80 percent of the PEs were Hypoxia related. 2. The human system, 

specifically the requirements for meeting human needs, was not represented in the 

integrated end-to-end description of the F/A–18. This omission made it difficult for 

system hardware engineers to find end-of-the line problems when isolated individual 

systems appeared to be working well. 

4b: There was and is hardly any data or measurements being taken in the F/A– 

18 that addresses the human response to the flight environment. Data needed includes: 

i. breathing patterns (rate, depth, volume) in flight 

ii. cabin pressure 

iii. Oxygen levels, flow and pressure in the breathing gas system 

iv. Exhaled CO2 levels in the mask 

Data such as the above serve two purposes: 1) as a monitor of human health in 

the dynamic flight environment, and 2) as specific diagnostic checks on components 

of the integrated life support system. 

Data that was collected included inflight sorbent tube samples from EA–18 Growlers of pilot breathing gas. This data, when investigated by NASA, demonstrated an 

unambiguous relationship between increased contamination and the occurrences of 

PEs. The Navy did not and has yet to conduct proper analysis on these samples. 

It is important to note that the relationship is one of correlation; NASA did not conclude that contamination was the cause of PEs. 

Mr. TURNER. a) Is the U.S. Navy capable of solving the PE problem? 

b) Has the Navy been forthcoming with all of their data? 

Mr. CRAGG. 6a: Yes. When the NASA investigation started, the NASA team saw 

dedicated individuals across the U.S. Navy doing their best to find and fix the PE 

problem. However, they weren’t working together in an organized way, and their 

central focus was on the plane—not on the pilot and importantly, not on the dynamic plane/pilot/environment interaction. 

6b: Yes. The Navy quickly provided us with everything we asked for. 

Mr. TURNER. The report notes in several observations and findings that your team 

found specific design problems with the F/A–18’s environmental control system, onboard oxygen generation system, and CRU–103 regulator. Can you explain those in 

detail? 

Mr. CRAGG. The F/A–18’s Environmental Control System (ECS) is fed high pressure air from a direct connection to the engine that varies in its pressure whenever 

the pilot changes the throttle. The ECS feeds other systems that must account for 

these pressure changes. One of these systems, the cabin pressure control system, 

is prone to instability which leads to pressure excursions in the cockpit. Others, like 

the onboard oxygen generation system (OBOGS) and CRU–103 regulator, appear to 

be delivering oxygen to the pilot in a manner inconsistent with nominal pilot performance for some flight regimes. Put simply, all evidence supports that the pilot 

is not getting the stable cabin pressure and breathing oxygen supply that he/she 

needs in some cases, due to complex system interactions and deficiencies in the design of the jet as an integrated system. 

However, more generally and more importantly, these problems are rooted in the 

lack of a (human system) ‘‘requirements driven’’ approach to the design and engineering of the integrated environmental control system, onboard oxygen generation 

system, and CRU–103. While these systems may indeed meet individual documented requirements; it remains evident that documented requirements are insufficient to comprehensively support pilot physiological needs. There remains a dearth 

of data surrounding the pressure and breathing performance needs of a human 

being operating the F/A–18; and by extension a dearth of data to support or refute 
68 

when these performance needs are being met or not met operationally by the aircraft. 

Put simply again; the ECS, OBOGS, and CRU–103 were specified based on an 

evolution of operational history and aircraft design legacy, rather than validated 

performance data used to evaluate pilot demands in the tactical jet flight environment. While this approach for hardware design is sufficient to support pilot performance in most cases; it supports no understanding of where the actual performance envelope lies, and therefore no ability to anticipate or evaluate when the performance envelope may be exceeded and result in a Physiological Episode. Additionally, the GGU–12 OBOGS unit and oxygen delivery schedule falls significantly short 

of meeting the newest requirements of MIL–STD–3050. This new standard collects 

the best information on meeting pilot breathing requirements for aircraft using 

OBOGS. The NASA team also pointed out that the CRU–103 pilot breathing regulator, while capable of providing additional pressure during periods of high-g force, 

as is done for example in the F–22, is not used in this manner in the F/A–18. This 

minor change in usage has been found to help pilots breath more easily during highstress combat maneuvers. NASA has not monitored the continuing execution of the 

program. However, the agency has been informed that the Department of Defense 

has fully accepted NASA’s finding that Physiological Episodes happen to people, not 

aircraft. According to the DOD, these findings have driven their Navy Physiological 

Episode Action Team (PEAT) to shape a holistic strategy that examines Physiological Episodes as an interactive condition between the human and the aircraft. Although physiological monitoring is not a near-term capability, the DOD has indicated the PEAT is aggressively pursuing acceleration opportunities and accelerating 

mitigations to the fleet, where DOD is looking at mechanical fixes to the machine 

but also directly assessing human health and performance in the cockpit. 

Mr. TURNER. The report notes numerous concerns with the Navy’s ‘‘Human System Integration’’ process. One finding stated that the process is ‘‘deficient’’. Can you 

elaborate on those concerns? 

Mr. CRAGG. The Navy’s Human System Integration process is indeed ‘‘deficient.’’ 

The Finding in question states: F10–30: Currently the Human-Systems Integration 

(HSI) process within the U.S. Navy is deficient; it appears to be associated with a 

decrease in the available subject matter expertise in the fields of Aerospace Medicine, Physiology, Human Factors Engineering, Cognitive Psychology, and Human 

Systems Integration, as well as organizational barriers to meaningful interaction 

amongst these disciplines across the U.S. Navy. NOTE: This finding is similar to 

one made in the USAF F–22 Life Support System review several years ago. In 2012, 

NASA was asked by the USAF to provide a review of the F–22 Life Support System. 

One of the major findings was a significant increase in the work-of-breathing for pilots during flight. This issue was primarily the result of a lack of thorough humanmachine interface testing in the flight environment. The work-of-breathing theory 

was evaluated by simply instrumenting a pilot wearing standard aircrew flight 

equipment and placing them in a centrifuge configured to replicate the life support 

system an operational F–22 aircraft. These data led to improvements in the F–22 

design and in the human performance associated with piloting an F–22. 

In 2012, USAF General Gregory S. Martin testified before Congress that (from the 

NASA report): 

‘‘Over the past 20 years, the capabilities and expertise of the USAF to perform 

the critical function of Human Systems Integration have become insufficient, leading to: 

—The atrophy of policies/standards and research and development expertise with 

respect to the integrity of the life support system, altitude physiology and aviation 

occupational health and safety. 

—Inadequate research, knowledge, and experience for the unique operating environment of the F–22, including routine operations above 50,000 feet. 

—Diminution of Air Force Materiel Command (AFMC) and Air Force Research 

Laboratory (AFRL) core competencies due to de-emphasis and reduced workforce to 

near zero in some domains.’’ 

Many of these same underlying Human-Systems Integration deficiencies are evident in F/A–18. 

Human-Systems Integration (HSI) is defined as the ‘‘interdisciplinary technical 

and management processes for integrating human considerations within and across 

all system elements; an essential enabler to systems engineering practice’’ (Haskins, 

2007). The goal of HSI is to integrate the human into the system as a critical element; the human is as critical to system design considerations as the hardware or 

software. 

With regard to fighter aircraft, the interaction of the human with the aircraft (i.e., 

human factors) is one particular domain that demands a great deal of attention be-
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cause of the complexities involved, and because of significant consequence associated 

with failure. This domain is the comprehensive integration of human capabilities 

and limitations (physical, sensory, cognitive, and team dynamics) into systems designed to optimize human interfaces and facilitate human performance in training, 

operation, maintenance, support, and sustainment of a system. The Department of 

Defense has formalized the role of HSI. There are nine domains of HSI: manpower, 

personnel, training, human factors engineering, occupational health, environment, 

safety, habitability, and human survivability. A commonly accepted HSI success 

story was the development of the F119 engine for the F–22 by Pratt & Whitney. 

Because both the USAF and Pratt & Whitney were dedicated to HSI the development constantly included the human element. The resulting design increased ease 

of assembly, maintenance, and repair thereby reducing overall labor costs, servicing 

frequency, and number of tools required. The USAF elevated the visibility of this 

process and the contractor also shared in this vision by creating testing facilities designed to better evaluate the engine to ensure reliability. Ultimately, the key to successful HSI is the fervent commitment from top-level leadership in maintaining the 

integral nature of HSI. This has not been the case in the F/A–18. 

To maintain the combat edge, weapon systems must change over their life cycle. 

This is a fact. However, these changes must be appropriately evaluated using an 

HSI analysis to explore the potential impact to the human. The F/A–18 life cycle 

has been extended for years beyond what was originally planned and has undergone 

a number of modifications ranging from structural to digital. There is a vast difference between the original F/A–18A ‘‘Hornet’’ and the EA–18G ‘‘Growlers’’. The oxygen system changed from liquid oxygen (LOX) to the OBOGS. The EA–18G received advanced radar, various electronics counter-measures components, and a second aircrew member who acts as the Weapons Systems Operator (WSO). These 

changes impacted the demand for engine bleed air but no rigorous assessment was 

conducted to determine if the engine bleed air can meet these demands while maintaining appropriate OBOGS oxygen concentration and flow throughout all phases of 

flight. Just as the aircraft changes over time, new understandings of human physiology also occur that must be considered in terms of the overall system. Indeed, 

even during initial design phases, assumptions about the human are made and 

sometimes these assumptions are not valid. Thus, the requirements based on incorrect assumptions or an incomplete understanding of human physiology can be costly 

to correct. In 1993, a study identified that pilots could over-breath the on-board oxygen generation system (OBOGS). A recommendation was made to change MIL–D– 

85520 to require the oxygen systems of tactical aircraft to produce peak inspiratory 

flow rates of at least 260 LPM (NAVAIR TM–93–59 SY). This recommendation was 

not implemented. It is noteworthy that MIL–STD–3050 (2015) now contains a similar minimum flow requirement. During the early stages of the spike in reports of 

F/A–18 PEs, the Navy assumed that the PEs resulted from a defect in the aircraft. 

The aircraft was taken out of service and inspected. No consideration was given to 

the integration of the human and machine during flight operations. While an inspection could determine if a component was operating within spec in a controlled environment, it remained unknown if the component performed as expected on the aircraft during dynamic flight. Furthermore, it remained unknown if these established 

specifications met the demands of the human system during flight, and if they continued to meet those demands following various system changes. The human was 

not considered as a critical element; the HSI was deficient. As new information 

about the machine and the human is learned, we now recognize that the physiologic 

requirements determined for the original system design were already partially inadequate. Due to the increased cooling needs in latest models of the F/A–18, this inadequacy has increased. The greatest concern is the lack of data to answer the question: how inadequate? 

It’s impractical to instrument an entire system of any significant complexity, however, key pieces of information are required to correctly diagnose problems. For example, the F/A-18’s pressure fluctuations are difficult to assess because there is no 

inlet or output sensor that directly records these data for analysis. This is a knowledge gap in terms of characterizing and assessing the machine performance. Similarly, there are critical knowledge gaps in characterizing the human system. In fact, 

the most important data required to identify and solve PEs is entirely absent; there 

is no data collected to objectively define the human physiological experience in the 

cockpit during operational flight. There is no routinely recorded data about oxygen 

pressure, flow, or percentage. Additionally, there is little data on pilot breathing 

rates, breathing volume, cabin pressure, etc. Without data, the human subjective report of a PE cannot be compared with in-flight exposure and potential causal factors 

cannot be confirmed or dismissed. Furthermore, without measurements to characterize the current conditions, it will be challenging to know if the results of the 
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Navy’s changes positively or negatively impacted the human. To be clear, the PE 

rate is a deeply insufficient metric as human participation can be influenced by various factors far easier than data. This is a hindrance to exploring and assessing the 

validity of any solution. 

Like the USAF in 2012, the Navy’s critical core competency of HSI expertise has 

atrophied due to a lack of investment and support. Currently, the emphasized expertise is aircraft engineering solutions. The best way to affect change for a humanmachine system is by integrating the human into the system and assessing that integration with each subsequent design modification. Without appropriate HSI expertise at the table, the most integral, intelligent, and valuable part of the system— 

the human—isn’t represented. 

Mr. TURNER. In the FY17 NDAA, this Congress directed the Secretary of the Navy 

to conduct an independent review of the plans, programs, and research of the Department of the Navy with respect to physiological episodes affecting aircrew of the 

F/A–18 Hornet and F/A–18 Super Hornet aircraft, as well as the efforts of the Navy 

to prevent and mitigate the effects of such physiological events. This subcommittee 

is interested in hearing what the Navy found valuable from NASA’s report and how 

are you using NASA’s findings today to inform future efforts with the F/A–18 series 

aircraft? 

Admiral JOYNER. The Navy found NASA’s report useful in identifying organizational constructs that were not working well to respond to the urgent issue of physiological episodes (PEs), including communication shortfalls, stove-piping of information, and lack of a single clear leader for PE efforts. NASA’s recommendations provided a catalyst for reorganization and the adoption of a broader view of the Naval 

Air Systems Command’s (NAVAIR’s) systems engineering boundaries when addressing the PE problem, specifically inclusion of the human factors and physiological 

needs in system design and function of the aircraft. Additionally, NASA bolstered 

support for a comprehensive Root Cause Corrective Action (RCCA) investigation 

that the Navy has fully embraced as the path to solving the PE issue. Below are 

NASA’s 8 key recommendations and the Navy’s actions: 1. Measure parameters that 

directly assess human health and performance. Make measurements in the cabin 

environment whenever possible. The Navy is exploring every option to measure and 

record meaningful data in the cockpit. Several development efforts are ongoing in 

coordination with PMA–202, the Aircrew Systems Program Office and the Navy Bureau of Medicine and Surgery (BUMED) to field sensors that can directly measure 

human performance and physiological response while not being intrusive or interfere with cockpit duties. While human-mounted sensor technology matures, integration of multiple sensors in the aircraft cockpit and aircrew flight gear continues. 

One example of a newly fielded sensor is the SlamStick, a small pressure sensing 

and recording device carried in aircrew pockets. SlamSticks are carried on every F/ 

A–18 and E/A–18 sortie. Data is downloaded after flight and uploaded to a central 

database for analysis. This data has been used extensively to characterize and understand the cockpit environment. 

Mr. TURNER. Navy leadership has consistently said physiological episodes are the 

number one safety priority within Naval Aviation as it is directly related to aircrew 

health. This Congress has consistently asked what it can do to help in this effort. 

As a result, the Budget Request for Fiscal Year 2018 was shaped to provide the financial resources required to address the issue. Can you briefly describe to the subcommittee what solutions are being accomplished with these funds? 

Admiral JOYNER. To address issues in the T–45, the Navy received resources in 

FY18 in the form of additional O&M funds which are funding the ongoing T–45 

Root Cause and Corrective Action (RCCA) investigations. The funds will also be utilized to fund a contract with the OEM (Boeing) to support the RCCA and provide 

Field Service Representatives (FSRs) at all Chief of Naval Air Training (CNATRA) 

T–45 training sites. Some examples for T–45 include: Enhanced Emergency Oxygen 

System (EEOS). Maximizes the oxygen storage capacity of the emergency oxygen 

system for retrofit of the SKU–10/A (F–18) and SKU–11/A (T–45) Seat Survival Kit 

Assembly. T–45 Oxygen Concentrator. Obsolescence issues with the T–45 OBOGS 

concentrator (GGU–7A), coupled with a need for additional reliability and safety enhancements drive a need for a replacement OBOGS concentrator. The GGU–25 was 

designed in 2008 by Cobham and was partially tested for use with the T–45. In 

FY18, the Navy funded F/A–18 PE efforts targeting three primary areas. The first 

was to fully fund all the RCCA requirements. The RCCA is investigating 427 

branches on the fault tree. Closure of these branches will require a massive data 

collection effort and engineering analysis. Below are some of the examples of RCCA 

efforts underway being funded by FY18 budget: Flight test—Multiple flight test effort are ongoing to collect data in support of the RCCA. The major effort is the extensive instrumentation of an F/A–18C to execute a flight test plan that will fully 
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characterize the dynamics of the ECS and breathing gas delivery systems. Manned 

and Unmanned aircrew and life support systems testing (KBRWyle Brooks, San Antonio)—will test aircrew and life support systems using pressure chambers and centrifuge to create realistic operational conditions to characterize and measure performance in a controlled environment. 

Mr. TURNER. The subcommittee understands the Navy stood up the Physiological 

Episodes Action Team (PEAT) to unify mitigation efforts across Naval Aviation, and 

address shortfalls in communication and data sharing between PEAT core members 

and external fleet stakeholders. While the subcommittee believes establishing the 

PEAT for these purposes makes sense for the Navy, we are interested in hearing 

what the PEAT is doing to find synergies within the Department of Defense, and 

how are these efforts being executed to find a solution? 

Admiral JOYNER. Finding synergies between organizations is part of the PEAT 

charter, which did not limit the team from looking outside of the Department of the 

Navy or Department of Defense. There are several aspects to investigating PEs: 

from analysis of the aircraft, determining what system effects are on the human, 

and developing strategies for current and future aircraft. The PEAT has engaged 

a broad swath of internal and external partners, including subject matter experts 

from United States Air Force (USAF), National Aeronautics and Space Administration, Federal Aviation Administration, industry, academia, medical, and dive communities. In addition, we’ve established regular fleet communication to share all 

data and progress related to PEs. While investigating the aircraft, we have leveraged work that was done by the USAF while conducting a review of the F–22 aircraft in 2012. Specifically, the methodology of using a Root Cause Corrective Action 

team and performing a rigorous analysis of root cause has enabled us to employ 

high-velocity learning and not repeat mistakes of past efforts. While determining 

human and physiological understanding, the PEAT has employed the efforts of the 

Naval Medical Research Unit-Dayton (NAMRU–D) to actively research multiple topics where medical understanding is immature. NAMRU–D enjoys a strong partnership with the USAF 711th Human Performance Wing (HPW) providing complementary capabilities for aeromedical research while supporting cross service collaboration in both research and experimentation. As we continue to research strategies for 

future aircraft, it should be noted that we are currently developing joint solutions 

for two shared aircraft-the T–6 and the F–35, and we are embedded with the Joint 

Program Office as well as the USAF’s PE team, being led by Brig Gen Doorenbos. 

We are sharing information and resources, which will yield a higher quality product 

for the warfighter. 

Mr. TURNER. The Chairman and Ranking Member of this subcommittee visited 

Naval Air Station Patuxent River, Maryland, on 15 September 2017 in an effort to 

see firsthand what the Navy is doing to address physiological episodes. It was a very 

informative visit and impressive to see the number of both active duty service members and DOD civilians dedicated to solve the current issues affecting F/A–18 and 

T–45 aircraft. As it was thoroughly described during the visit, could you please 

briefly explain to the subcommittee the processes set in place when a physiological 

event happens, how the investigative process is performed and what the feedback 

mechanism is to return findings and information back to the aviators? 

Admiral JOYNER. Physiological Episode (PE) reporting protocol commences when 

aircrew reports physiological symptoms during or after flight. Safe recovery and aircrew treatment are prioritized above any and all data collection or reporting requirement. Aircrew are met plane-side by an ambulance for initial evaluation and 

treatment, if required. The data collection and reporting effort are guided by three 

Naval Safety Center forms, Parts A/B/C. Part A is used to capture the aircrew’s narrative of the flight and PE event, mission type and profile, environmental conditions 

and self-reported aircrew symptoms. Part B directs the aircraft be placed in a 

‘‘down’’ status and prescribes numerous diagnostics tests and inspections of the aircraft and aircrew flight gear as well as a thorough review of the aircraft maintenance history. Part C documents the medically relevant data collected during postflight evaluation by a flight surgeon, including previous medical history, 24-hour 

physiological and human factors history, all post PE findings and treatment. The 

reporting squadron is assisted by the PE Rapid Response Team (PERRT). Upon report of a PE, the squadron’s Safety Officer (or duty officer in his absence) will notify 

the cognizant Aeromedical Safety Officer (AMSO—aerospace physiologist), flight 

surgeon, and Naval Aviation Technical Representative or Field Service Representative. The PERRT is collectively responsible for ensuring all data collection and reporting requirements are complete. Additionally, they will assist the squadron in 

the decision to return both the aircraft and aircrew to flight. The data collected by 

the PERRT, including SlamStick cockpit pressure data, recorded aircraft flight data, 

and post-flight findings are immediately shared with all stakeholders for review and 
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analysis. Ideally, there is enough data within the first 24 hours to provide immediate feedback to aircrew and the squadron on causality of the PE. In some cases, 

where more extensive testing or engineering investigation is needed, feedback may 

be delayed up to 30 days. Ultimately, PE information that is collected and investigated is submitted into the Naval Safety Center’s WESS Aviation Mishap and 

Hazard Reporting System (WAMHRS) as a hazard or mishap investigation report. 

The hazard or mishap investigation report is released using WAMHRS providing a 

link to the report. This link is transmitted to safety personnel using a collection of 

email addresses called a community of interest. This provides feedback on evidence, 

analysis, causal factors and recommendations to prevent recurrence as well as subsequent endorsements and responses to recommendations in the report. 

Mr. TURNER. The NASA report states that ‘‘The Navy has not conducted a fleet 

wide survey of their F/A–18 air crew to understand the PE problem from the human 

perspective, where these physiological events actually occur’’. Why has such a survey not been conducted? 

Admiral JOYNER. The Physiological Episode Action Team, in concert with Naval 

Postgraduate School (NPS) developed and administered a comprehensive aircrew 

survey. The survey was broadly distributed amongst F/A–18, EA–18, and T–45 aircrew and maintainers. The survey concluded 02 Feb 2018. Over 1,400 responses 

were received, reflecting participation from 21.6 percent of the Fleet, which is considered statistically significant to provide a representative sample of Fleet opinion. 

NPS, in conjunction with the Center for Naval Analysis, are currently compiling and 

analyzing the data and results which will be used to inform the Root Cause Corrective Action investigation. 

Mr. TURNER. The NASA report notes that the F/A–18’s oxygen monitor—the 

CRU–99—does not log data, but that the plan to replace it with the more advanced 

CRU–123 was cancelled. Is that the case and if so why was this upgrade canceled? 

Admiral JOYNER. The CRU–123 program was launched to incorporate a low pressure warning and data logging capability for the aircraft’s oxygen system. Funding 

constraints at the time resulted in these requirements being allocated to a new oxygen monitor: the CRU–123. PMA–265 spent years developing the CRU–123 for the 

F/A–18. Numerous setbacks eroded confidence in the manufacturer’s ability to 

produce a product that would meet the reliability requirements for the F/A–18. The 

Navy cancelled the CRU–123 program for the F/A–18 after a lengthy development 

effort in which the CRU–123 repeatedly failed qualification standards and was unable to survive the harsher operating conditions encountered by the F/A–18 as opposed to the T–45 which has successfully flown with CRU–123. PEAT acknowledged 

the need for data logging, and current planning includes the installation of a limited 

number of CRU–123s to assist in data collection while waiting for Cabin Pressure 

and OBOGS Monitoring System (CPOMS) development and fielding. In addition to 

needing a robust and reliable system for this critical function, the Navy shifted 

course to the CPOMS to take advantage of additional capabilities that could provide 

aircrew increased real-time in-cockpit situational awareness of critical life support 

systems’ health. CPOMS will incorporate a digital display that will replace the current analog cabin pressure altimeter and provide an easy to read display of cabin 

pressure and warnings for schedule deviations of cockpit pressure, oxygen concentration and flow. CPOMS also has critical growth potential for desired features 

such as integrated cautions and warnings on current aircraft displays, and the ability to automatically perform actions, such as selection of emergency oxygen under 

certain degraded conditions or system malfunctions. The requirement to log critical 

OBOGS performance data is now allocated to the CPOMS and the new concentrator 

for the F/A–18, which is in development by the Aircrew Systems and F/A–18 and 

EA–18G program (PMAs-202 and 265) concentrator. This new approach will provide 

data recording on the aircraft’s data bus, which is a significant improvement over 

the earlier approach to record it remotely on the CRU–123. 

Mr. TURNER. How is the Air Force addressing physiological events, and onboard 

oxygen generation system issues with sister services? 

General NOWLAND. The Headquarters Air Force Unexplained Physiologic Event 

(UPE) Integration Team and the Navy’s Physiological Episodes Action Team 

(PEAT), both led by General Officers, continue to work closely together to investigate in a complimentary manner. Together, they have engaged abroad range of internal and external partners, including subject matter experts from the Air Force 

and Navy, National Aeronautics and Space Administration (NASA), Federal Aviation Administration (FAA), Industry, academia, along with medical and dive communities to resolve these issues. 

One area where the USN and USAF are working together is in aircrew air quality 

assessment. The 711th Human Performance Wing has developed systems to test aircrew air quality in flight such as the real time air quality sensor (RTAQS) which 
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is in-line air supply monitor that detects contaminants and elucidates OBOGS function. It is being used to baseline T–6 (USN/USAF), T–45 (USN), and F–18 (USN) 

aircraft and is also prepared for use in the F–16 (USAF). Additionally, we have established an OBOGS lab that allows us to replace flight conditions and test the performance of OBOGS to detect abnormal performance. This lab has been used to support both USAF and USN UPE investigations. 

Another area of collaboration is in aircrew physiological sensing. The 711th HPW 

in collaboration with industry, academia and government partners have developed 

several aircrew physiological state sensing systems. Some, such as VigilOx and 

Mask Sensing System (MASES), monitor inhaled and exhaled air but others assess 

tissue oxygen saturation, core temperature, heart rate, etc. VigilOx is slightly ahead 

of some of these other technologies and is undergoing verification and validation 

testing. Due to the urgency of the UPE issue, it has been flight tested in the T– 

38 (USAF) and F–18 (USN). Four devices have been delivered, two for testing and 

one each to the USAF and USN for preemptive operational assessments. Our end 

goal with this sensor development is to feed into an autonomous life support system 

that will adjust to keep the pilot in a physiologically safe condition. 

Finally, the 711th Human Performance Wing has a robust collaborative relationship with Naval Aeronautical Research Unit-Dayton (NAMRU–D). The 711th HPW 

with NMRU–D have collaborated with several academic, governmental, and industry partners in exploring how the human body responds to the unique stressors of 

the flight environment. We continue to explore such topics as hypocapnia, 

hyperoxia, hypobaria, work of breathing, contamination, pulmonary function, and 

environmental priming—all issues that may precipitate ‘‘hypoxia-like’’ symptoms. 

The 711th HPW’s unique location with NAMRU–D is particularly fortunate as this 

affords the two organizations to leverage each other’s expertise and move forward 

as one entity on many of the research efforts. 

Mr. TURNER. Why is root cause attribution to physiological events so difficult to 

ascertain? 

General NOWLAND. The root cause for Unexplained Physiologic Events (UPEs) has 

been difficult to ascertain, primarily due to the lack of in-flight cockpit sensors to 

verify both the content of the breathing gas mixtures from the oxygen system (oxygen concentration, flow, pressure), and the physiologic status of the aircrew (expired 

oxygen/carbon dioxide levels, heart rate, respiratory rate, blood oxygen saturation). 

Such sensors are currently in development and will be able to objectively determine 

the root cause of physiologic events by measuring these variables and characterizing 

the integration between the human, the cockpit environment, and aircrew flight 

equipment. Until such sensors are in place, investigations to assess the cause of 

UPEs must resort to modeling human physiological response based on extrapolated 

assumptions of aircraft system performance as gas delivery, rather than the actual 

data itself. In addition to the lack of sensors, the extremely low rate of UPEs makes 

it difficult to identify trends which could be used to indirectly identify possible root 

cause of these events. 

The two principal means to mitigate the hazards associated with high altitude 

flight are to provide increased concentrations of oxygen in aircrew breathing gas 

mixtures (to prevent hypoxia), and to pressurize cockpits to prevent adverse effects 

associated with a hypobaric environment. In modern aircraft, cockpit pressurization 

is provided by engine bleed air supplied to the Environmental Control System 

(ECS). Oxygen for the breathing gas mixture comes from either a Liquid Oxygen 

Supply or an ‘‘On-Board Oxygen Generating System (OBOGS), which also uses engine bleed air to supply breathing gas to aircrew. The non-specific nature of UPE 

symptoms (e.g., lightheadedness, headache, confusion) and the complexity of the 

interaction between the oxygen system, aircrew flight equipment, and the aircrew, 

makes it challenging to identify the root cause of many Pes. 

Current aircrew monitoring systems undergoing testing and evaluation at the 

711th Human Performance Wing include, Canary, VigilOx, physiologic health status 

of isolated personnel (PHYSIO), and mask sensing system (MASES). 

QUESTIONS SUBMITTED BY MS. TSONGAS 

Ms. TSONGAS. The committee has been examining the issue of elevated PE rates 

in F–18 aircraft for more than two years. Throughout that time, we have been told 

that improvements to the GGU–12 onboard oxygen generation system were an important part of reducing the risks of such events. As a result, I was troubled by several things the NASA report had to say about this specific piece of critical equipment on F–18s. First, in paragraph 10.2.2 the report states that ‘‘The first and most 

significant thing to note about the GGU–12 is the disconnect between best practices 
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of pressure swing absorption systems and operating conditions of the GGU–12 . . . 

Best engineering practices for effective gas separation using PSA is constant conditions. [However], the GGU–12 is fully dynamic—nothing about the GGU–12 is constant.’’ The report further states that ‘‘The GGU–12 is tested in the lab and in the 

field with clean, dry air with a fixed flow rate and fixed inlet pressure. This does 

not match any actual operating conditions. The GGU–12 testing program does not 

adhere to the best practice summarized by ‘fly what you test and test what you fly’.’’ 

Finally, the report’s finding 10–1 has this to say about the underlying design 

standards for the GGU–12: ‘‘The NESC team found evidence that traced the oxygen 

peak flow rate requirement to outdated information from the 1960s, which apparently neglected to address newer information on pilot breathing demands document 

in Navy TM–93–59–SY. The GGU–12 OBOGS maximum performance requirement 

does not meet human system demand requirements for flow and oxygen concentration during all phases of flight.’’ Does the Navy have a plan to upgrade the OBOGS 

system in the F–18? What is the schedule? Is there a cost estimate? When would 

fielding commence and be complete? When will Navy OBOGS systems in F–18s 

meet the updated military specifications published in 2015? 

Admiral JOYNER. NASA is correct that best practices for a Pressure Swing Adsorption (PSA) technology is to maintain constant operating conditions. While this 

practice is well suited for a stationary industrial air separation plant, it certainly 

presents a challenge for an advanced high altitude all weather fighter aircraft operating in extreme conditions. The F/A–18 OBOGS actually represents a significant 

step forward in the maturation of supply air integrity and stability. The F/A–18 was 

the first fighter attack aircraft to move the bleed air supply from a direct engine 

bleed port where the temperature and pressures vary widely, to a diversion off of 

the aircraft’s Environmental Control System (ECS) where the temperature, pressure, and water content of the air supply is significantly more stable. The F/A–18 

was also first to introduce a redundant bleed air route that continues to provide 

source air to the OBOGS in the event of an ECS failure. Finally, the GGU–12 was 

fully qualified across environmental conditions which include bleed air temperatures 

ranging from ¥15 to +250F and in ambient temperatures from ¥65 to +160F. In 

actuality, the GGU–12 as installed in the F/A–18 receives conditioned air from the 

ECS that are well within these design parameters. Regarding testing, NASA is confusing routine performance checks with qualification testing. The GGU–12 was fully 

qualified against robust temperature and pressure extremes that exceed the actual 

environment in which it operates. Decades of reliable performance would attest to 

this assertion as well as more recent checks conducted to support the Root Cause 

Corrective Action (RCCA) investigation. It is true that many of the performance 

checks conducted by the fleet are performed at ground level using hangar air with 

flow conditions that are not reflective of aggressive flight. However, it is incorrect 

to assume that these conditions are inadequate to identify a failing system. It is 

noteworthy that the U.S. Navy is the only service that performs routine testing of 

the OBOGS for prognostic health monitoring. This test, which is performed on the 

aircraft every 84 days is designed to catch a failing OBOGS before it results in an 

aborted flight or physiological event. This comprehensive system test checks the system’s ability to produce oxygen, the health of the sieve beds, the timing circuits, the 

accuracy of the low oxygen warning sensor, the oxygen plumbing integrity, and the 

ability of the system to enunciate failure conditions. In addition, the GGU–12 is removed from the aircraft every 400 flight hours for a more stringent off-aircraft test. 

This approach is in compliance with MIL–STD–3050. It is fair to say, however, that 

there is a dearth of information across the services and our international partners 

regarding the life and longevity of an OBOGS. The validity of the pass/fail criteria 

used by the Navy is being validated under a surveillance program to better understand the natural degradation in OBOGS. To date, none of the 28 F/A–18 or 28 T– 

45 aircraft that have undergone this very demanding test have shown significant 

degradation in their molecular sieve or carbon monoxide catalyst. NASA is also incorrect in applying the recommendation of Navy TM–93–59–SY to the GGU–12 oxygen concentrator. The intent of TM–93–59–SY was to establish dynamic breathing 

requirements for OBOGS plumbing and breathing regulators. The F/A–18 OBOGS 

plumbing is designed to absorb the pneumatic shocks and cyclic flow demands of 

human breathing. It does this by using a 100 cubic inch plenum for each cockpit. 

The size of the plenum and the diameter of the oxygen plumbing are designed to 

maintain the oxygen pressure at the pilot’s breathing regulator so that it performs 

well. Thousands of data files from F/A–18 and EA–18G operations using pilot monitoring equipment have confirmed that there is more than adequate supply pressure 

being provided at the pilot’s breathing regulator to meet human system demand requirements. The primary shortcomings of the GGU–12 center on the lack of oxygen 

concentration control and the lack of recorded data. Both of these requirements are 
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new since the CY2015 release of MIL–STD–3050. PMA–265 and PMA–202 are developing a new concentrator for the F/A–18 that will address these issues. 

QUESTIONS SUBMITTED BY MR. GAETZ 

Mr. GAETZ. I understand that many in the military and aerospace communities 

feel that the reasons for the physiological events plaguing military aviation are mechanical. However, in light of the continuing problems with hypoxia in our frontline fighter and training aircraft, has anyone within your respective Services collaborated with academic institutions with known expertise in human performance 

and aerospace physiology/medicine. Has that option been talked about or explored 

in any way? 

Mr. CRAGG. We believe this question is better answered by both the U.S. Navy 

and the U.S. Air Force. 

Mr. GAETZ. I understand that many in the military and aerospace communities 

feel that the reasons for the physiological events plaguing military aviation are mechanical. However, in light of the continuing problems with hypoxia in our frontline fighter and training aircraft, has anyone within your respective Services collaborated with academic institutions with known expertise in human performance 

and aerospace physiology/medicine. Has that option been talked about or explored 

in any way? 

Admiral JOYNER. Yes, Navy is actively engaging with academia. The Johns Hopkins University Applied Physics Laboratory will assist in contaminant evaluation of 

the collected Hydrocarbon Detectors and Sorbent Tube Adapters. The Naval Air Systems Command (NAVAIR) Educational Partnership Program will be hiring a PhD 

Chemist from St. Mary’s College to assist in PE efforts. Also, NAVAIR AIR–4.6 has 

hired Aeromedical experts to consult on the review of PEs in the Aviation Environment Scientific Advisory Board. Stanford University’s ‘‘Hacking 4 Defense’’ will start 

working on this problem in April 2018. This is a no-cost collaboration with graduate 

and undergraduate students who will look at the OBOGS-Hypoxia linkage with a 

naı ̈ve/fresh set of eyes. Members of the team will be from disciplines that include 

pre-med, computer science, engineering, etc. Stanford University has recently done 

work with the U.S. Navy to include proposals to prevent/reduce PEs with Special 

Warfare SEAL Delivery Vehicle drivers caused by multiple ascents/descents during 

long missions. 

Mr. GAETZ. I understand that many in the military and aerospace communities 

feel that the reasons for the physiological events plaguing military aviation are mechanical. However, in light of the continuing problems with hypoxia in our frontline fighter and training aircraft, has anyone within your respective Services collaborated with academic institutions with known expertise in human performance 

and aerospace physiology/medicine. Has that option been talked about or explored 

in any way? 

General NOWLAND. The Air Force remains committed to solving unexplained physiologic events across the fighter and training aircraft. Academic institutions play a 

vital role in helping understand the role of human factors in physiologic episodes. 

The 711th Human Performance Wing (HPW), the Air Force’s aeronautical research 

facility, with Naval Medical Research Unit—Dayton (NAMRU–D) have collaborated 

with several academic institutions like Case Western Reserve University, Norwegian University of Science and Technology, and the University of Notre Dame in 

exploring how the human body responds to the unique stressors of the flight environment. We continue to explore such topics as hypocapnia, hyperoxia, hypobaria, 

work of breathing, contamination, pulmonary function, and environmental 

priming—all issues that may precipitate ‘‘hypoxia-like’’ symptoms. 

The Air Force continually explores additional options to collaborate with other 

academic institutions to leverage their expertise in contribution to help better understand the problem space. Institutions like Embry-Riddle Aeronautical University 

have specialized expertise the Air Force can leverage to help identify human errors 

associated with physiologic episodes; provide data-driven recommendations for addressing human error; and recommend improvements for current human factors 

data collection. 

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