Air Force seeks maker of G-suit in fatal crash

The Air Force is trying to identify the maker of a life-support garment worn by a Nellis Air Force Base pilot who blacked out from high gravitational forces and was killed when his F-16 fighter jet crashed in rural Nevada last year.

Even though the accident investigation is closed, the search continues for a record of the garment’s serial number, which could be traced back to the manufacturer of some G-suits that failed. Investigators concluded Capt. Eric Ziegler’s blackout was not caused by a failed G-suit.

The military’s heightened interest in the June 28 crash that killed Ziegler near the Nevada Test and Training Range was sparked by concerns voiced by a former fighter pilot and crash investigator from Las Vegas.

Bill McWilliams, a retired colonel who was vice-commander of the Tactical Fighter Weapons Center at Nellis, says the crash brings to light the government’s inability to track and recall G-suits that might be vulnerable to failure. Such failures were reported in 2003 after fabric specifications had been changed.

While no one will ever be certain what caused Ziegler to lose consciousness, McWilliams said he wants the Air Fore to reopen its investigation of the crash to help correct problems with the government’s system for tracking its inventory of anti-G force suits.

“Here’s a critical part of a pilot’s life-support system and there is no trail from the Defense Logistics Agency or the manufacturer to the bases and the lots they came from,” said McWilliams, who sat on 14 accident investigation boards and safety panels in his Air Force career.

“They’ve already said they don’t know where it came from. And that’s the crux of why it needs to be reopened.”

He said the agency’s “repeated statement that (it) does not provide failed G-suits to operational units … is flatly unprovable and is so common sense as to verge on being condescending if not insulting.”

His comments came in interviews last week after reviewing more than 100 pages from the crash report’s summary, a ruling by the Armed Forces Board of Contract Appeals and emails from defense agency officials.


One Air Combat Command officer acknowledged officials are trying to piece together a paper trail that would confirm the origin of Ziegler’s G-suit, but he said investigators still think Ziegler blacked out from causes other than a faulty G-suit.

“We’re attempting to confirm whether the available information could be used to identify the manufacturer,” said the officer, who spoke on background Thursday.

He was referring to a local identification number that was assigned to life-support equipment used by Nellis pilots. This ID number could then be correlated with the manufacturer’s serial number for the G-suit.

The chapslike garment worn around a pilot’s legs and abdomen contains bladders that inflate to prevent blood from pooling during acceleration from turns and rapid maneuvers when pilots experience high gravitational forces.

In theory, the G-suit system works in tandem with the pilot’s own efforts to counter the effects of high G-forces by automatically increasing pressure in the bladders in proportion to the rapid G-force onset. The bladders inflate with pressurized air connected through a hose in the aircraft.

The portion of Ziegler’s G-suit with the serial number wasn’t recovered. Search teams, however, recovered a remnant of his G-suit.

“The two snaps were still snapped together and the bottom of the zipper was still engaged. This indicates at the time of the mishap, the waste zipper was properly closed,” according to the investigation report.

The investigation board, headed by Brig. Gen. Donald J. Bacon, had no reason to conclude that Ziegler’s G-suit was a factor in the crash, according to the Air Combat Command officer. “The suit was anything but an extremely remote possibility as a contributing factor.”

The board concluded that Ziegler, a 30-year-old pilot with more than 1,000 hours flying F-16s, blacked out from high gravitational forces. Bacon’s report cited a “preponderance of evidence” that Ziegler didn’t perform muscle restraining techniques to deter losing consciousness as he sped downward at 750 mph to evade a wingman in a simulated dogfight.

An Air Combat Command spokesman, Lt. Col. Edward T. Sholtis, said the fact that the pilot experienced G-force induced loss-of-consciousness, or G-LOC, “is not a negative reflection on Capt. Ziegler.”

“Fighting G-LOC during a series of high-performance maneuvers places extra­ordinary physical demands on fighter pilots, and there is always risk that even the most exceptional pilots may lose consciousness during the seconds that make the difference between a successful training flight and a tragedy,” Sholtis said Friday.


Several manufacturers supply G-suits to the Air Force, Navy and Marines. Officials at Air Combat Command head­quarters in Langley, Va., said they are attempting to determine the brand and supplier’s lot number of Ziegler’s G-suit to find out if it was acquired after 2003. That’s when a change in fabric specifications resulted in failures of some garments during high-pressure endurance tests at one production plant, Derm/Buro Inc.

DuPont made fibers used in Derm/Buro G-suits and those from other garment suppliers. The company notified the Defense Supply Center in Philadelphia in March 2002 that it had changed the color of its fibers to address the military’s night-visibility concerns.

“We are unable to determine the precise date when DuPont began supplying the new fibers to fabric manufactures,” according to the appeals case ruling.

McWilliams said the Accident Investigation Board glossed over the possibility of G-suit failure and apparently wasn’t aware of a 2009 ruling. An administrative judge found DuPont’s changes made the fabric less effective for enduring the high-pressure expansion of the bladders.

The law judge ruled that the military changed fiber specifications without Derm/Buro’s knowledge. A hearing in the case is scheduled for Tuesday in Falls Church, Va., to address compensating Derm/Buro for increased costs to correct defects stemming from the specification change.


McWilliams said the failure of G-suits in testing after the coloration change is reminiscent of problems that occurred in F-111A Aardvarks, a multipurpose strategic bomber that had experienced engine test failures before one crashed in 1979. The crash occurred after the Air Force had authorized modifications to the engines to operate at higher temperatures.

McWilliams visited the engine production facility and traced the problem to bearing failure. He concluded that lubricants broke down at those higher temperatures, resulting in carbon deposits that, in turn, caused bearings to fail.

He said one reason to reopen the Ziegler crash investigation, if nothing else, is a passage in the appeals case ruling about what happened after the coloration change.

On Aug. 7, 2003, a suit from one lot failed end-item testing. The fabric “in the abdominal region of the suit ruptured during endurance testing.”

The rupture was the first experienced by the manufacturer, which “had timely delivered from 500 to as many as 1,200 suits per month for a total of approximately 32,000.”

Later, on Aug. 28, 2003, two more production lots failed leak tests “for failure to hold the minimum pressure required.” The inspection team discovered that a hose assembly was defective.

But Air Combat Command spokeswoman Kelly Sanders said, “It is highly unlikely that a suit that failed manu­facturer testing made it into the government inventory.”


Command officials believe there is only a remote possibility that Ziegler’s G-suit contributed to the F-16 crash. Command officials said records show Ziegler’s G-suit was “inspected thoroughly” by unit specialists less than a month before the crash.

During the May 31 inspection, the G-suit would have been fully expanded as if in a 9-G turn and then inspected for signs of stress, wear and tear. Ziegler also inspected the G-suit before his flight and he had conducted a number of high-G maneuvers in the same suit on previous missions and during the fatal flight, officials said.

But McWilliams pointed out there is no way to know for sure if Ziegler’s G-suit was defective if a G-suit can’t be traced to a specific lot and manufacturer. Investigators also noted in their report that there was a gap in the paperwork trail for certifying that Ziegler’s garment fit properly.

No recommendations for improving the Air Force’s tracking system were made in the Ziegler case. However, recommendations typically aren’t released to the public.

“They are tracked internally by the Air Force to ensure air crew and aircraft safety,” Sanders said.

Despite Bacon’s statement that there was a “preponderance of evidence” that Ziegler didn’t perform an anti-G force straining exercise, there was no video or transcripts that outline the final moments of his flight.

The procedure is supposed to be repeated until G forces on the body return to normal, or 1 G, the gravitational force at sea level. Ziegler likely sustained 8 to 9 Gs, the investigation board reported.

G-suits that fail testing are quarantined, according to Defense Logistics Agency spokeswoman Michelle McCaskill.

She said 954 designed to the 2003 specifications were put in the government’s inventory last year.

But only a tiny fraction — two garments from every lot of 500 and one bladder from not more than 501 — are randomly selected for endurance tests on mannequins at ground level to simulate G-force conditions. If one garment fails the test, the lot is rejected.


McWilliams said, “The bland statement that service representatives were present when the investigation of failures was in process, and at the board proceedings does not excuse the lack of even a hint of follow-through or corrective action.”

Air Force officials say G-suits are tracked and accounted for in a database maintained and updated by air crew equipment personnel at the unit level. “The unit has some discretion in deciding how detailed their tracking system is, but they are required to maintain a record of the item’s serial number,” one official said on background.

McWilliams said unit identification numbers or serial numbers “have no value if the G-suit user doesn’t know who manufactured the particular G-suit series (or lots) and has no evident way of finding out.

“To make matters worse, if a G-suit fails in flight at a critical time, resulting in or contributing to the disastrous consequences that conceivably might have occurred in this instance, do you simply write it off as ‘We don’t know.’ Or, ‘It’s too hard to examine what the AIB (accident investigation board) pointed out?’ I dare say that would be a most controversial way to conduct business under any circumstance, and totally unacceptable to an operating command using potentially defective G-suits.”

Contact reporter Keith Rogers at or 702-383-0308.

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