A freak collision with a large bird--probably a 15- to 20-pound pelican--brought down a $280-million B-1B bomber on a test flight over Colorado last September, the Air Force said Wednesday in its official investigation report on the accident.
The bird slammed into the plane as the craft was traveling at 600 m.p.h. and the bomber's thin aluminum skin was ruptured just above the right engines, ripping a critical hydraulic line and starting a 3,000-degree fuel fire that doomed the giant jet. Three Air Force officers died in the crash, one because his ejection seat malfunctioned, the report said.
Early Theory Discounted
An early theory that the plane had flown through a flock of birds and sucked several of them into its large engines proved wrong, officials said.
The crash was the first for a B-1B bomber, and Air Force Brig. Gen. James W. Meier called the bird strike a rare and "extremely unlucky" accident. He said that the plane is designed to withstand high-speed collisions with 5- to 6-pound birds or lower-speed strikes by large birds. He said that no other B-1B had ever hit so large a bird and that the Air Force has had little experience with similar collisions involving other planes.
The B-1B was flying over an Air Force bombing range near La Junta in southeastern Colorado when the accident occurred. The day before, an Air Force officer in the area reported "several hundred" migrating North American White Pelicans flying between two small lakes on the test range.
After the accident, the Air Force suspended low-level, high-speed flights of the plane. It said that it will spend $62.5 million to reinforce three vulnerable points of the B-1B's skin. The modifications will be done by Rockwell International, the plane's prime builder, and the Air Force, and are expected to be completed by the end of this year.
The B-1B, the Air Force's first new front-line bomber in 25 years, is designed to penetrate Soviet air space by flying at high speeds close to the ground. It is supposed to employ sophisticated electronic defensive measures to fool Soviet radars.
Its capabilities are now in question because of the bird accident on Sept. 28 and previously reported problems with the bomber's radar-jamming systems.
The Air Force spent $28 billion to design and build 100 of the advanced bombers. The last B-1B rolled off Rockwell's assembly line in Palmdale, Calif., Wednesday. Revisions in the plane's electronic systems are not expected to be complete until 1991.
Saw a White Blur
According to the official account of the accident, the B-1B took off from Dyess Air Force Base near Abilene, Tex., at 7:57 a.m. en route to the La Junta bombing range. At 9:32 a.m., after a refueling stop, Capt. Lawrence Haskell, a pilot trainee flying the plane, saw a white blur shoot by the nose of the plane. An instant later, the six-man crew heard a loud bang and felt a shudder in the rear of the plane.
Maj. James Acklin, a flight instructor, took the controls and radioed a military air controller that the plane had hit a bird or birds and had an engine fire. He climbed to 3,500 feet, swept the variable-angle wings forward to reduce airspeed and tried to regain control of the plane, which had begun to roll to the right.
Later investigation showed that the bird's impact broke a key hydraulic line, causing a fire that melted a fuel line, setting off an intense fire. Unable to regain control, Haskell told ground controllers the crew was going to eject.
Crew's Last Words
"We gotta get out!" were the crew's last words on the radio transcript.
The automated ejection system catapults the four ejection seats in order, with the pilot last. The third seat in the sequence, the co-pilot's, malfunctioned and Maj. Wayne Whitlock, another flight instructor, went down with the plane. The two other crash victims, Acklin, and pilot trainee Lt. Ricky Bean, were in extra jump seats that are used on training missions and do not have ejection devices.