Air Force Says Stealth Fighter Crash Is Due to Missing Bolts

MIDDLE RIVER, Md. —  A $42-million Stealth fighter lost a wing during an air show and crashed in a neighborhood Sept. 14 because maintenance workers failed to install four bolts, the Air Force said Friday.

An investigation found that only one of five 1-inch fasteners that help keep the wing in place was put on back in January 1996 while the F-117A was undergoing repairs.

Two later maintenance checks failed to spot the problem, even though one of those checks was prompted by a pilot who said the wing had too much “flex,” said Col. John Beard, head of the investigative panel.

“It is my opinion the accident was caused by unintentional maintenance oversight,” Beard said.

Air Force Maj. Mike Wagner, a member of the investigating team, said parts of the wing began to vibrate “like a flag whipped by the wind” as the plane flew past the crowd at an air show near Baltimore.

It caused the wing to snap. The pilot ejected safely as the plane crashed and burst into flames.

No one on the ground was hurt, but one house was destroyed and several others were damaged.

A change in the design of the bat-wing plane may have made it harder to detect the problem. In 1992, Lockheed Corp. added two steel plates to stiffen the wings. The plates covered the missing fasteners, and maintenance workers would have had to spend 14 hours taking apart the whole assembly to see the mistake, he said.

The names of those responsible for the missing bolts were lost when maintenance records were transferred from paper to computer, Beard said.

The Air Force has inspected its entire fleet of 53 F-117A planes since the crash and found no other fighters with the same problem, Beard said.