'Oversight' blamed in crash of fighter jet Wing fasteners missing since Jan. 1996, panel finds

December 13, 1997|By Jay Apperson | Jay Apperson,SUN STAFF

As investigators sifted through the wreckage of a stealth fighter that crashed in Baltimore County, they quickly focused on a white, gutter-shaped piece of half-inch-thick aluminum.

On the piece of metal, taken from inside the crumpled jet's wing, they found four holes where they should have found four bolts and white paint where they should have found bare metal.

In a news conference at Martin State Airport yesterday, Air Force Col. John H. Beard pointed to the recovered part as the key piece of evidence in the probe of the F-117A crash Sept. 14. Announcing a panel's finding that "unintentional maintenance oversight" was to blame for the crash, he said the missing bolts caused the plane's left wing to weaken and fall off.

Beard said the fasteners had been missing since January 1996, when the wing component was taken apart, stripped of paint, reassembled and repainted.

Two later inspections, including one performed after a pilot reported that the plane's wing seemed to be misaligned, failed to uncover the oversight, he said.

"In my opinion, the check perhaps could have been a little more thorough," Beard said.

Incomplete maintenance records have prevented investigators from pinpointing which Air Force technicians incorrectly installed the part, Beard said.

He also said the problem was "isolated" and that no similar problem was found on the remaining 53 Air Force stealth fighters.

The fighter crashed into a Bowleys Quarters neighborhood while making a flyby as part of an air show at the Middle River airport. Thousands of spectators watched as the plane's left wing broke off and the plane tumbled from the sky.

The plane exploded in a fireball that damaged two houses, but the pilot parachuted to safety and no one was seriously injured. Residents have been compensated nearly $300,000, said Col. Victor Donovan, head of the Air Force team handling damage claims.

After the crash, the Air Force convened a five-member investigation board. In explaining the findings yesterday, Beard, a command pilot who led the first air combat mission in the Persian Gulf war, said Lockheed Martin engineers quickly zeroed in on the "Brooklyn Bridge" assembly.

"It was before my board was even convened, which was two weeks after the crash, that Lockheed's engineers had already discovered that, in fact, four fasteners were not there and were well on their way toward determining that the four fasteners were the cause," Beard said.

He also explained how the paint job told the tale: Most holes were surrounded by a thin, unpainted ring -- the outlines of the fastener collars. But four holes showed no such ring and showed white paint inside the hole.

Beard said the plane's design was changed several years ago when a steel plate was added to the assembly to stiffen the wing. When the plane's wings were removed and reinstalled in January 1996 at Holloman Air Force Base, N.M., four of five fasteners in a section of that part were left off, according to the report.

Because the plate obscured the missing fasteners, no one could have seen the mistake without removing the assembly, which would have taken 14 man-hours, Beard said. "Based on the evidence, it is my opinion that the accident was caused by unintentional maintenance oversight during the left Brooklyn Bridge assembly re-installation in January 1996," he said.

In July 1996, the wing assembly was inspected at Holloman by three technicians using a mirror and a flashlight to look for loose and missing fasteners, but no problem was discovered, according to the report.

A year later, a "chase pilot" behind the fighter reported that part of the left wing seemed to be 2 inches higher than it should have been, but a check did not uncover the problem.

Beard said it will be up to commanders at Holloman to determine whether any technicians should be disciplined.

Pub Date: 12/13/97

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