Raising concerns in Washington DC: F-35 oxygen system causing breathing issues for pilots
WASHINGTON — A subcommittee of the U.S. House's Armed Services Committee, whose members include local congressman Rep. Matt Gaetz, is asking the Department of Defense and NASA to investigate the problematic pilot breathing system aboard the fifth-generation F-35 Lightning II stealth fighter jet and to take steps to correct any issues.
The oxygen delivery system aboard the F-35 has long been a subject of concern, and was noted as a contributing factor in the May 19, 2020, nighttime crash of an F-35 assigned to the 58th Fighter Squadron of the Eglin Air Force Base-headquartered 33rd Fighter Wing on an Eglin runway.
The pilot was able to eject safely from the aircraft as it landed at too shallow an angle, but the $176 million fighter jet was destroyed. An Air Force Accident Investigation Board (AIB) report on the crash indicated that the pilot had been having some trouble sleeping in the days prior to his fateful flight, but went on to offer some serious commentary on the oxygen delivery system.
According to the report, the pilot "noted that he usually feels more fatigued in the process of flying this aircraft than his previous aircraft, the F-15E." Further, "It is known amongst the F-35 flying community that the oxygen delivery system is very different than legacy oxygen delivery systems (delivery systems used in older aircraft), such as the one used in the F-15E."
The report says that, in augmenting pilots' exhalation and inhalation, the F-35 system "is not instantaneous" and "cause(s) many pilots across the F-35 platform to report feeling more fatigued than normal when compared to their prior legacy aircraft."
The House Armed Services Committee's Subcommittee on Tactical Air and Land Forces makes its request for assessment and action on the F-35 breathing system in its "mark-up" review and comment on the latest National Defense Authorization Act, the defense spending and policy bill now making its way through the House and the U.S. Senate in advance of the Oct. 1 start of the new federal fiscal year.
At some point, the two separate versions of the bill will be reconciled by a combined House and Senate conference committee before being sent to President Joe Biden for action.
In its mark-up, the subcommittee references a November 2020 report from NASA's Engineering and Safety Center Technical Assessment Report on the effects of breathing gear on pilots' breathing and performance aboard a number of military aircraft, including the F-35.
The F-35 gets almost 200 references in the 519-page report, the preparation of which included interviews with F-35 pilots. Specifically, the NASA document notes, "(f)ive F-35 pilots were interviewed on their in-flight experiences" and "(a)ll of them reported experiencing breathing difficulties in the F-35."
In a listing of findings specifically regarding the breathing system, the NASA assessment notes that among other things, the "measured pressure, flow and timing response of the breathing system is inconsistent."
"For a given pressure, the amount of flow at the beginning, middle, and end of the breath is unpredictable, and can be chaotically different," the assessment says.
Elsewhere in the report, the NASA safety center notes that "(s)uch rapid changes in the breath-to-breath supply forces the pilot to continually compensate by adjusting breathing rate, volume and exhalation/inhalation force."
Other findings note that it "noticeably discourages normal breathing function via high-pressure, pressure surges, and hyperoxia (excessive oxygen supply)."
Additionally, the NASA report says the breathing systems appear to function differently among individual F-35s and that pilots "report that exhalation and verbal communication can be difficult in the F-35, including reports of being cut off mid-speech by mask pressure fluctuations, while talking."
But in line with the subcommittee recommendation, the report notes shortcomings in the assessment and suggests a need for more work.
"Taken alone, the two F-35 limited data sets and five pilot reports cannot be used to draw statistically significant conclusions," NASA notes, "... but these data do support findings that suggest the possibility of significant systemic design, integration or performance deficiencies ... ."
"More importantly, the evidence, taken together, fully supports a strong recommendation that additional data and pilot experience be collected to fully understand the situation and implement corrective actions, as necessary," the report says.
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