By John M. Donnelly, CQ | Feb. 23, 2016
The director of Pentagon weapons testing is questioning claims by the general in charge of the F-35 fighter jet program that potentially deadly flaws in the plane’s ejection seats have been largely fixed.
The testing official, Michael Gilmore, also confirmed the accuracy of CQ reports last fall disclosing that the F-35’s flawed ejection seat poses a serious risk not just to the lightest weight F-35 pilots, as some Defense Department officials have suggested, but also to pilots weighing up to 200 pounds.
At issue is a glitch in the F-35’s ejection seat revealed through mannequin tests. Pilots, especially lighter ones, during ejection rotate into a position that can cause their necks to snap when a powerful rocket-propelled parachute is fired from the seat.
Safety assessments revealed last October by CQ show that pilots weighing 136 pounds or less are all but certain to be killed when the ejection seat’s parachute rockets out in certain scenarios. Pilots weighing less than 136 pounds are currently barred from flying the planes as a result, though there are now no F-35 pilots that are under that weight.
More importantly, however, the tests conducted last summer showed a 1 in 4 risk of fatal injury to pilots weighing up to 165 pounds — which comprises nearly 1 in 3 pilots, according to historical records.
Significantly, Gilmore said in written responses to questions this week that he has seen no evidence that any tests have been run using mannequins weighing between 137 pounds and 244 pounds — the weight range for most military pilots. That raises questions about the safety of the majority of the military’s F-35 pilots, who fly for the Air Force, Navy and Marine Corps.
A senior Air Force official said last fall that the service considers the F-35 ejection seat risk “serious” for pilots up to 200 pounds due to the testing failures on lightweight mannequins and the absence of tests using average-weight mannequins.
Asked if he agreed with the Air Force’s “serious” risk assessment for pilots up to 200 pounds, Gilmore said, “Yes.”
“Testing with mannequins of various weights would provide more data for the services to conduct risk assessments associated with the ejection sequence,” he said.
‘High Loads on the Pilot’s Neck’
In a roundtable with reporters Feb. 10, Air Force Lt. Gen. Christopher Bogdan, head of the F-35 program, said his office oversaw three tests last fall to assess a pair of solutions to the problem first revealed in tests last summer. The first fix is a switch that pilots weighing less than 136 pounds can hit to delay the release of the parachute by fractions of a second — enough so the pilot’s body readjusts in the seat so it’s in a better position when the parachute releases. The second solution is sewing material into the seat to restrain a pilot’s head from going too far backward.
“Both those fixes have already been tested and already worked,” Bogdan said, adding that they are “ready to go into the field and into production by the end of the year.”
The only remaining challenge that Bogdan acknowledged was that the weight of a new helmet, which may be exacerbating the whiplash problem, must be reduced before the ban on pilots less than 136 pounds can be lifted.
Gilmore had a much different take.
Tests to date have been done either on unusually light mannequins (136 pounds or less) or on extremely heavy ones (245 pounds), but nothing in between those weights, Gilmore’s written comments show. Consequently, there is no data that could shed light on risks to the majority of pilots.
What’s more, the only ejection seat tests in the last three years that have not put unacceptable stresses on the necks of mannequins have been conducted on those weighing 245 pounds.
While Bogdan described last fall’s tests as having demonstrated only that the two solutions “worked” and cited no problems, Gilmore pointed out shortcomings and in two of those tests.
Specifically, in an Oct. 15 test with a 103-pound mannequin, the material that had been sewn into the seat to restrain the head succeeded in keeping the parachute release from snapping the mannequin’s neck, Gilmore said. However, he added, the material “does not prevent the high loads on the pilot’s neck due to rocket firing and wind blast.”
A Nov. 19 test with another 103-pound mannequin was meant to assess both fixes: the switch for lightweight pilots and the material head restraint. But, the combination of solutions was not enough, Gilmore said, as “neck load exceedances were still observed during the initial catapult and wind blast phases . . . and during the parachute opening phase.”
The third test, a Dec. 11 trial with a 245 pound mannequin, showed no problems.
More Data Needed
Gilmore also pointed out other reasons to believe last fall’s tests are not the final word. First, he said, the trials were conducted “by contractors for the program office,” not independent assessors. He also said his office has not received the data from these tests, only summaries by the program office.
Gilmore noted, too, that he’s “concerned about the lack of information or plans from the program office” for testing ejections in conditions where the plane is out of control or damaged. He said there may be “additional risk to the pilot” in these circumstances from pieces of the cockpit canopy, which shatters by design ahead of the ejection sequence.
He said several testing conditions must be in place before anyone can say, as Bogdan did, that the ejection seat fixes have worked. The seat must be tested on the full weight range of mannequins. They must be wearing a new lighter weight helmet. The conditions tested must include those where the plane is damaged or out of control. And the raw data, not just summaries, must be submitted to the testing office.
Until then, Gilmore said, “we cannot assess whether the fixes work and are ready to field.”
The fixes would then need to be incorporated into the planes, he said.
Lastly, Gilmore rebutted a statistic frequently used by Bogdan to minimize the risk to F-35 pilots, which he has used repeatedly before lawmakers and reporters: that the risk to an F-35 pilot ejecting and dying due to an ejection seat flaw is 1 in 50,000.
But Gilmore said those odds are minimal because the figure takes into account the small chance that a pilot will have to eject in the first place. When the risk is assessed on the odds of a pilot surviving an ejection if it occurs, the odds worsen drastically, according to the Pentagon safety documents signed by Bogdan.
“However, when the situation requires ejection, the ejection seat and life support equipment should function reliably and properly,” Gilmore said. “The low probability of an actual ejection should not reduce the importance or value of having an ejection seat that provides an opportunity for the pilot to survive the ejection. Also, the seemingly low probability cited by the program likely does not include the risk of needing to eject in combat due to battle damage.”
The F-35 program office had not responded by press time to repeated requests for comment.