Physiological Events down 62%

The Pentagon has improved the Physiological Event problem seen on aircraft since about 2017, with events down 62%, but a number of events went unreported to the public. Between 2017, when the alarm was first sounded about PE episodes, and 2022, which was the latest fiscal year, there were 1,543 events reported. Of those the Air Force T-6A had 285 incidents. The F-18E had 134, the F-16 114, F-18C 91, and the EA-18G with 91. Unreported were PEs on larger aircraft, with the E-3 Sentry having 16 events, with only 31 aircraft.

Most PEs were reported as hypoxic events, but they ranged from spatial disorientation to G induced loss of consciousness, to reactions to smoke and air pressure changes. Most events were self reported or flagged as hazards, with 253 in 2018, down to 105 in 2021. The numbers went back up in 2022, with 114. Roughly one third of the events were severe enough to be considered mishaps, with 155 in 2017, dropping to 28 in 2022. Most of mishaps were recorded at Class C or D, which are damages between $25,000 and $600,000 or an injury that keeps someone from work. Those dropped from 130 in 2017, to 17 in 2022.

There were three undisclosed Class A mishaps during this time period. Class A mishaps result in $2.5M in damage or a fatality. Class B mishaps result in $600,000 to $2.5M in damage, or permanent disability, or the hospitalization of three or more personnel. The first Class A was an F-15C in Oregon, March 21, 2019. A student pilot was rendered unconscious during a training flight. He was able to land the aircraft safely, but the aircraft suffered $2.5M in damage. An investigation wasn't launched, because while the aircraft suffered $2.5M in damage, it wasn't destroyed.

August 2, 2018 a Marine Corps UH-1Y Super Huey suffered an undisclosed Class A mishap. Details were not provided, as the information was declared controlled unclassified information.

The third accident was August 5, 2017, when a Navy F-18F Super Hornet suffered an undisclosed Class A mishap.

In 2022 there were no Class A mishaps reported. In 2017, there were five Class A mishaps, with a Navy EA-18G, F-5N, F-18F, F-18C, and an MV-22B involved. In 2017, the Navy admitted that four F-18 pilots had died from a lack of oxygen in the cockpit since 2007. Navy T-45 Goshawk pilots refused to fly the aircraft after PE events spiked in that fleet.

Both the Air Force and the Navy formed action teams to bring the numbers down. The Air Force reported 400 PEs between 2017 and 2022, with all being hypoxia like symptoms. They involved seven airframes. The F-15, F-16, F-22, F-35, A-10, T-6 and T-38 airframes. They reached a high with 135 in FY18, and dropped to 40 in 2022. The Air Force has most of the PE reports from 2022, with the T-6A at 42, F-16C at 11, A-10C at 9, T-38C at 9, and F-35A at 6. The Air Force accounted for three quarters of the FY22 PEs. The F-35 fleet reported 44 events over 6 years, with the Air Force F-35As being responsible for 32, and six of seven in FY22. Since 2019, the Navy and Marine T-6 fleet has reported fewer than 10 episodes a year, while the Air Force reported 40 a year for their T-6As.

All the attention has been on the fighter fleet, but the KC-135 reported 5 PEs last year, the same as the T-45, EA-18G, and F-18E, while the E-3 reported four. In the six years reported the KC-135 reported 33 incidents, the C-130 32, and the MH-60S 27.

The services found root causes for 94% of reported PEs, but are still looking at them through specific lenses. For example the Navy has determined that hypoxia is not to blame for most breathing difficulties. The Air Force on the other hand looks through most events through the lens of hypoxia. Multiple paths are being taken to combat the events, from a new version of OBOGS to getting a new breathing system that delivers oxygen rich gases faster, to training and monitoring various systems.

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