The House Armed Services Committee’s (HASC) tactical air and land forces panel wants the Pentagon to submit a report on the pilot breathing system for the Lockheed Martin [LMT] F-35 fighter after a National Aeronautics and Space Administration (NASA) report last November pointed to hypoxia-like incidents and cognitive impairments among F-35 pilots.

The HASC tactical air and land forces panel’s portion of the committee fiscal 2022 National Defense Authorization Bill requires Defense Secretary Lloyd Austin, in consultation with NASA Administrator Bill Nelson, to investigate, assess, and implement corrective actions for F-35 breathing system problems noted by the technical assessment of tactical and training aircraft breathing systems last Nov. 19 by NASA’s Engineering and Safety Center (NESC).

In early 2017, the U.S. Navy requested NESC to perform an independent review of physiological episodes across the service’s F/A-18 fleet.

The NASA report last November on pilot breathing systems and physiological episodes encountered by pilots of T-45, T-6, and F/A-18s over the last few years included a “quick excursion” into such incidents on two F-35 aircraft and interviews with five F-35 pilots, a HASC aide said on July 28.

“The F-35 breathing system noticeably discourages normal breathing function via high-pressure, pressure surges, and hyperoxia,” per last November’s NASA report.

The report said that there is “a distinct breathing system disparity across F-35 aircraft with no clear explanation or solution,” that “symptoms are frequent and variable among pilots and tend to mimic pilot-specific hypoxia symptoms,” and that the F-35 breathing system “could result in cerebral (brain) hypoxia and cognitive disorders, and/or create conditions of increased work of breathing, excessive fatigue of respiratory muscles, and non-specific respiratory discomfort.”

NESC said that its hypothesis that the F-35 breathing system caused such impairments is a hypothesis as yet untested in the flight environment.

“I was trying to log into the [computer] to document the standard post-maintenance debrief,” according to one F-35 pilot comment included in the NASA report. “It’s an incredibly basic thing, just logging into a computer that I’ve done over and over again. But I kept logging in over and over again with the wrong password. I had to ask the maintenance individual there, why I couldn’t log in and they were like ‘you’re straight up using the wrong login name and password.’ It was really obvious to them that it was kind of an inappropriate. I was inappropriately confused at that point. Nothing manifested in the air, but I could definitely detect a cognitive slowing and confusion on the ground, after landing.”

Other F-35 pilot comments in the NASA report pointed to cognitive harm. “I’m just slow,” per the pilot’s report comment. “It’s like you just stare at something for however long, for 20, 30 seconds and you’re like ‘I’m just staring at it… and I need to… I know what I need to do… but,’ [I can’t].’”

The HASC aide said July 28 that the committee contacted the F-35 Joint Project Office at Patuxent River Naval Air Station, Md., to get its perspective on the report, but “they kind of discounted the NASA study and the fact that it wasn’t a formally sanctioned or designed test, or as detailed as they would have liked to have seen.”

The F-35 JPO “kind of discounted it as, ‘They looked at two aircraft. They had limited sensors available for their use,'” the aide said. “They [the F-35 JPO] really didn’t lend it [the NASA report] much credit.”

HASC intends that the DoD report on the F-35 breathing system lead to any needed changes in the breathing system to avoid complex and costly retrofits.

“Looking at all the physiological episodes that have occurred across tactical air platforms–the F-22, F/A-18, T-45, T-6–over the years, unfortunately, it’s taken Congress to get the Department [of Defense] to look at those issues and take action,” the HASC aide said. “Based on those past actions with those aircraft, we’re doing the same with the F-35.”

The aide said that the F-35 has had more than 40 physiological episodes of various types, and the NASA report noted that the first such F-35 physiological episodes surfaced in pre-production testing in 2012.

“We want to make sure that instead of the pilot having to adapt to the jet, the jet needs to make sure that it complies with military specifications required for pilot breathing systems,” the HASC aide said. “The pilot shouldn’t have to think about breathing in the airplane. It should just come naturally so that they can focus on the tactical employment.”

On July 29, the F-35 JPO wrote in email responses to questions that “55 in-flight and on-ground physiological events have been reported as of July 1, 2021.”

“The JPO is engaged and sponsoring ongoing F-35 pilot breathing research studies with other independent experts including NASA Engineering and Safety Center, Air Force Research Labs, Naval Medical Research Unit Dayton, and others,” per the email responses. “This work also provides a framework for future studies to address improved pilot breathing on the F-35 Life Support System (LSS). In addition, the JPO is also pursuing LSS improvement projects that seek to improve pilot breathing and address potential contributors to PEs [physiological events].”

While the JPO said that it did not agree with NESC’s report findings because of what JPO termed low sample size, the use of an unvalidated aircraft sensor,  and “the lack of an approved and authorized test plan,” the JPO also said “our current plan of action is in line with the NESC’s overall recommendation to further investigate the performance of the F-35 LSS.” The JPO said it has taken the comments of the five pilots into account “as part of feedback from pilots across the fleet through venues such as the F-35 Physiological Event Team (PET), LSS Bi-weekly, F-35 Aeromedical Community of Interest, and pilot forums.”

“The JPO relies heavily on feedback from the pilot community as well as formal PE reporting to identify areas of improvement,” the office said.

The NASA report said that the agency interviews indicated that up to 50 percent of F-35 pilots have experienced “undesirable symptoms at least once.”

“In more severe cases, the aircraft is actively causing acute injury, which, in rare but concerning instances, has demonstrated the potential for permanent disability,” per the report. “At least one pilot has been medically retired from military service with demonstrated pulmonary changes from his service entry.”

The NASA assessment said that “despite highlighting these issues and requesting that the design of the F-35 breathing system be investigated, a number of the pilots interviewed believe that there is undue pressure to ascribe breathing problems to pilots and suppress information about these problems.”

Per the F-35 JPO July 29 email, “all reported physiological events are investigated and adjudicated via the F-35 PET,” and “pilots are directly involved in the PET process as they provide a first-hand account to the team.”

“The JPO also seeks-out continued user engagement through various pilot forums every year, explaining the PE process and encouraging pilots to report issues,” the JPO said.

Beside the F-35, the HASC tactical air and land forces’ portion of the fiscal 2022 defense authorization bill addresses military tactical aviation shortfalls in general.

“Despite billions of dollars of investment in developing and acquiring tactical fighter aircraft over many years, the Air Force, Navy, and Marine Corps will likely continue to face capability and capacity shortfalls over the upcoming decades,” per the HASC panel’s mark, which notes that a Government Accountability Office (GAO) report in 2010, GAO-10-789, projected that the military services would face such shortfalls in 2020.

“Given that the services are still facing tactical fighter aircraft inventory and capability shortfalls more than a decade after the last GAO report on the issue, the committee directs the Comptroller General of the United States to submit a report to the congressional defense committees not later than April 1, 2022, that assesses and identifies current Air Force, Navy, and Marine Corps tactical aircraft capability and capacity requirements and forecasted shortfalls,” per the subcommittee’s mark. “In addition, the report should assess the extent to which the services’ tactical aircraft acquisition and modernization investment plans, including NGAD [Next Generation Air Dominance] efforts, are likely to meet those requirements and address the shortfalls.”

The U.S. Navy, for its part, recently told lawmakers on the HASC tactical air and land forces panel that the service expects to resolve its strike fighter shortfall by fiscal 2025 (Defense Daily, July 19). That would be five years earlier than the Navy had projected last year.

“We are scratching our heads on how the Navy moved up their analysis in terms of eliminating the shortfall by about five years,” the HASC aide said on July 28. “One, they didn’t reinstate the 36 Super Hornets that they were going to procure in [fiscal] ’22, ’23, ’24 and also took out about 104 aircraft out of their service life modification [SLM] program. Also, their NGAD program is still pretty much on the same timeline that it was last year.”

The aide said that, despite the Navy’s goal to put Block II Boeing [BA] F/A-18E/F Super Hornets through SLM in one year at a cost of between $7 million and $8 million per aircraft, the cost and timeline “are nearly double that.”