F-35 Pilot Killed in April Crash May Have Ignored Aircraft Instruments: Selva

Air Force Gen. Paul Selva said recently that the Japanese F-35A Joint Strike Fighter pilot who was killed in an April crash into the Pacific Ocean may not have listened to what his aircraft was telling him.

Japan Air Self-Defense Force officials concluded recently that Maj. Akinori Hosomi probably suffered from spatial disorientation, a condition in which pilots lose their sense of equilibrium, before crashing on April 9, 85 miles east of Misawa Air Base.

"The thing we won't know from the accident investigation is what the pilot tried to do -- if he tried to do anything to recover," Selva, the outgoing vice chairman of the Joint Chiefs of Staff, told reporters at a June 18 Defense Writers Group. "So, if you have never suffered from spatial disorientation, then describing it away as something you can technically fix is just hard to do."

Selva described the special chair that the U.S. military uses to simulate what going through spatial disorientation feels like.

"Basically, what they do is they have you lower your head and they spin you like a merry-go-round, and then they ask you to turn your head either right or left," he said. "And while the chair is spinning, they say 'sit up' and they stop the chair. ... I guarantee you that when you experience it, you won't know which way is up ... and that is just in a chair on the ground with one G of gravity."

In flight, environmental factors add to the condition to the point where "you will believe your eyes before you believe your body," Selva said.

"If you are flying on a starlit night, where the stars reflect over the ocean, your eyes can't tell you which way up is," he said. "If you become spatially disoriented -- which means your inner ear has been defeated -- so you have ... maneuvered the aircraft in a way that causes the fluid in your semicircular canals to flow in a way it doesn't normally flow. Then all of your sensory processes in your body can't tell you which way is up, and it doesn't matter how hard you try. You won't be able to do it."

Selva said he experienced the condition early in his career while flying near the Aurora Borealis, or Northern Lights, in "a non-maneuvering aircraft with the autopilot on, flying straight and level."

"The Aurora Borealis was vertical to the horizon. It was at night and, after about 30 minutes of flying with that visual perception, I felt like we were in a 90-degree turn because I was believing my eyes," he said.

Selva said the only thing he could do to solve it was to get up and walk to the back of the airplane, get a cup of coffee and look down into the coffee and see that it was not at 90 degrees.

"A single-seat fighter with multiple inputs doesn't have that and, if that individual got himself into a position of true spatial disorientation, he truly would not have known up from down, right from left," he said.

Crashes as a result of spatial disorientation in the military are relatively rare, but they do happen, Selva said.

"The only thing you can do to defeat spatial disorientation when you are that disoriented is believe what the airplane is telling you," he said. "Assuming it is still in controlled flight ... you have to believe what the instruments are telling you and, if you can't convince yourself to do that, you won't recover from the spatial disorientation. It's physically impossible."

-- Matthew Cox can be reached at matthew.cox@military.com.