Air Force investigators who probed the June 28 crash of an F-16C fighter jet that killed Capt. Eric Ziegler should have focused more on the life-support garment he was wearing when he blacked out over the Nellis training range moments before the crash, according to a lawyer for a company that makes the anti-G suits.
The lawyer said he fears some anti-G suits in the military's inventory are flawed because a Defense Department agency changed specifications for fibers in the garments, making some of them defective over time. The suits are designed to reduce the effects of high gravitational forces on pilots.
"While no one can know with 100 percent certainty why Captain Ziegler experienced G-LOC (loss-of-consciousness), unless action is taken to correct the anti-G suit defect, similar unexplained tragedies will befall other service members," Steven Karalekas, an attorney for anti-G suit manufacturer Derm/Buro Inc., said Thursday.
Air Force investigators concluded in a final report released in November that Ziegler, a 30-year-old pilot from West Fargo, N.D., blacked out because he didn't adequately perform a muscle straining exercise in the cockpit. The maneuver prevents loss of consciousness from high gravitational forces.
But Karalekas claims if investigators had looked more closely into the possibility that Ziegler's anti-G suit failed, the Air Force Accident Investigation Board would have known that the Defense Logistics Agency had changed the specifications for anti-G suit fibers without the manufacturer's knowledge.
Derm/Buro found the garments made under the defense agency's defective specification caused bladders to fail in tests at ground level and certainly they would have failed in the air at high altitudes.
"This change was the sole and direct cause of anti-G suit failures that occurred during destructive endurance testing. If the suits fail on the ground, they're going to fail in the air," Karalekas said.
Anti-G suit bladders for the pilot's calves, thighs and abdomen are supposed to automatically inflate with pressurized air connected through a hose in the aircraft to prevent blood from pooling in the pilot's legs.
The Accident Investigation Board determined in its 31-page report that Ziegler, an experienced pilot with more than 1,000 hours flying F-16s, most likely didn't effectively perform an anti-G muscle contraction and breathing procedure to increase blood flow to his eyes and brain.
The report said 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.
The crash occurred on public land, 150 miles north of Las Vegas, 26 minutes after Ziegler departed Nellis Air Force Base and during the fourth engagement with a wingman's aircraft at about 18,000 feet above sea level.
During the simulated air-to-air dogfight that Ziegler's aircraft was engaged in with the second F-16C jet, he "likely sustained 8 to 9 Gs" as he performed an evasive, near-vertical descent at more than 750 mph, according to the investigation report.
But a copy of a 2009 ruling by the Armed Services Board of Contract Appeals supports Derm/Buro's claim the Defense Logistics Agency changed color specifications for fibers that Derm/Buro obtained from a supplier. Materials used for the coloration change resulted in the failure of some anti-G suits that were tested at random.
The board's finding was based on testimony of a diverse group of textile experts as well as detailed laboratory analysis.
"We are persuaded based on the totality of the record and the preponderance of the evidence that the 'coloration change' caused the fabric ruptures experienced by appellant. That change reduced the ability of the cloth and suits to withstand destructive endurance testing," Administrative Judge Robert T. Peacock wrote in the contract appeals board's 71-page decision on May 27, 2009.
That means some anti-G suits out of thousands worn by pilots in the Air Force, Navy and Marine Corps might contain defective fibers that could result in the garment's bladders bursting.
A spokeswoman at Air Combat Command in Virginia wouldn't comment Friday on whether the Accident Investigation Board led by Brig. Gen. Donald J. Bacon was aware of the Derm/Buro case.
"The board investigated available evidence to determine the cause of the crash," command spokeswoman Kelly Sanders wrote in an earlier email to the Review-Journal.
"Information on whether or not a specific piece of information was considered, when, and why, if not discussed within the accident investigation board's report, generally is not releaseable," her email states, citing congressional statutes that limit public information on Air Force accident investigations.
She deferred to a Pentagon spokesman, Maj. Chad Steffey, when asked what steps are being taken to ensure U.S. military pilots aren't wearing anti-G suits made under the questionable specifications noted in Derm/Buro's appeal.
Steffey, in turn, said he raised the issue with the Defense Logistics Agency on Wednesday.
"They are looking into your questions about specification changes to the G-suit cloth and what specs are now being used for purchase," he said in an email.
Air Force investigators noted a gap in the paperwork trail for certifying that Ziegler's garment fit properly.
A discrepancy in an overdue date on the garment's inspection card was blamed on "a documentation error from the actual fit check date not being entered into the computer data tracking system as opposed to the fit check not being accomplished."
Air Combat Command officials, however, said they had no record of the make, brand or lot number for the anti-G suit Ziegler was wearing.
"Air Force procedures do not require the manufacturer information to be maintained in the G-suit inspection records," said Sanders, the command's spokeswoman.
She noted that a number of manufacturers supply Nellis Air Force Base with anti-G suits.
She said the part of Ziegler's G-suit that contained that information wasn't recovered from the crash site. "Therefore, it is unknown who manufactured his specific suit."
However, Ziegler's G-suit zipper was recovered. "The two snaps were still snapped together and the bottom of the zipper was still engaged. This indicates that at the time of mishap, the waist zipper was properly closed," according to the investigation report.
The report further states, "There was no evidence to suggest a malfunction in the ... G-suit."
An outside expert and former military pilot who served on accident investigation boards said the evidence of only remnants of Ziegler's G-suit, among other things, seemed to be lightly touched on by the board.
The Air Force Accident Investigation Board apparently was unaware of the change in G-suit fiber specifications that surfaced in the case before the Armed Services Board of Contract Appeals, "and therefore didn't look into the possible failure in the G-suit," according to the expert who offered his opinion on background.
Before the first mock-combat engagement on June 28, Ziegler had performed what fighter pilots call a "G warm-up," which involves a 90-degree turn involving 4 to 5 Gs. The warm-up ensures that a pilot's G-suit with its five inflatable bladders, the pressure breathing equipment and the inflatable bladder in the helmet are working properly.
He also had completed a G awareness maneuver, a 180-degree turn that involves up to 7 Gs to allow the pilot to practice the anti-G straining maneuver.
Evidence recovered from the crash site revealed that Ziegler "was leaning forward in his seat consistent with being unconscious, his right shoulder further forward than his left," the report said.
Two witnesses observed that no attempts were made to recover the aircraft from its dive, "again indicating that the (pilot) was unconscious at the time of the mishap."
Despite statements in the investigation report that Ziegler had performed a G warm-up and a G-awareness maneuver, Bacon, the investigation board's president, wrote that he found "clear and convincing evidence" that the accident was caused by Ziegler losing consciousness from high gravitational forces with "preponderance of evidence" that he blacked out because he didn't adequately perform the anti-G straining maneuver.
Yet, the "clear and convincing evidence" that Air Force investigators found was questioned by the outside expert because there were no witnesses or video from the cockpit, or radio transmission mentioned in the report that would confirm that Ziegler did or did not perform the anti-G straining maneuver.
Karalekas, Derm/Buro's attorney, said the type of anti-G garment illustrated in the investigation report -- CSU-13 B/P -- is the same type that failed endurance testing after fiber specifications had been changed.
"Clearly, if this can happen to a pilot of Captain Ziegler's talent and experience, one can only image the risk posed to newer, inexperienced pilots. ... Action is needed now to address and correct the problem. Thus far, it is not apparent that the Defense Department is addressing the problem," he said.
Contact reporter Keith Rogers at firstname.lastname@example.org or 702-383-0308.