A congressionally mandated review has been unable to determine why air crews of Navy F/A-18 Hornets and F/A-18E/F Super Hornets have experienced an increase in oxygen deprivation and other physiological episodes (PEs) over the past few years, according to a report by NASA’s Engineering and Safety Center (NESC), which performed the study.

But NASA offered several recommendations it said could help speed up the search for a resolution. They include collecting more data, such as measuring breathing patterns during flight, recording cabin pressure, measuring oxygen in the breathing gas system and recording carbon dioxide in the oxygen mask.

A Navy F/A-18 Super Hornet.  Photo: Boeing.
A Navy F/A-18 Super Hornet. Photo: Boeing.

NASA welcomed the recent appointment of Capt. Sara Joyner to lead the Navy’s aviation PE efforts, saying a single leader is needed to coordinate and prioritize work. But NASA suggested it was unhelpful that Boeing [BA], the F/A-18’s manufacturer, “was not fully involved” in PE efforts until recently.

“As the NESC team visited different U.S. Navy facilities, the lack of Boeing presence was conspicuous,” NASA wrote. “When the NESC team interviewed Navy engineers, many individuals noted their isolation and inability to ask Boeing questions related to design, qualification, configuration or performance. A notable exception was found at Royal Australian Air Force (RAAF) Base Amberley, where there was a strong Boeing-Australia presence and a close working relationship between Boeing-Australia and RAAF.”

In a statement, Boeing gave a different assessment of its role, saying it has been “working closely” with the Navy on the PE issue since 2010.

“Earlier this year, we were elevated to co-leads of the [Navy’s PE] team, and pulled resources from across the enterprise to assist,” the company said. “This is a top priority for Boeing.”

To try out potential fixes, the NASA report recommends that the Navy partner with Amberley, whose personnel “are committed to finding the cause(s) of PEs and implementing corrective actions.”

Congress, through the fiscal year 2017 defense authorization act, directed NASA to conduct the PE review because the problem has persisted despite the Navy’s implementation of corrective actions.

A NASA representative was scheduled to discuss the review’s findings at a Dec. 13 hearing of the House Armed Services Committee’s tactical air and land forces panel. But the hearing was postponed without explanation.