Saturday, September 29, 2001
Dyess B-1s flying out for repairs
By Sidney Schuhmann
Reporter-News Staff Writer
The Air Force has finally scheduled repairs
for cracks found a decade ago in the B-1B bomber’s tail section.
Mechanics at Tinker Air Force Base in Oklahoma
City, Okla., will be making the tail sections of the bombers safer
and sturdier over the next six years, the Air Force News reported.
It’s not unusual for planes to go through
repairs as they get older, said Tom Tomaras, a former B-1 pilot
living in Abilene.
“It’s going to be a permanent
fix that will extend their life,” he said.
Dyess Air Force Base, home to 40 B-1s, declined
to comment on the repairs.
A poorly designed substructure on the $225
million bomber and assembly flaws are probably to blame for the
cracks, said John Morgan, a B-1 structural engineer.
“Ten years into the aircraft’s
life, we started seeing some failures,” he told the Air Force
News, a military news service, earlier this month.
The Air Force owns 93 B-1s, which were built
in the early 1980s.
Cracks in the horizontal stabilizers on
the tail sections of B-1s were discovered in the early 1990s.
Further inspections revealed the problem was fleet-wide.
Horizontal stabilizers are 25 feet long,
8 feet wide and 1 foot deep. They enable the bombers to “pitch
and roll” — or climb, dive and maneuver. The stabilizers
are made of aluminum skins with 25 titanium spars running lengthwise.
A number of aluminum ribs crisscross the spars.
The substructures are built to last the
aircraft’s lifetime — 10,000 flight hours. Some bombers
recently eclipsed the 5,000-hour mark.
Tomaras said the cracks are not serious
and will not affect the bombers flying.
“They were like stress fractures,”
he said. “Metal fatigues when you shake it up and it cracks.
It wasn’t in a necessarily critical position on the tail.”
B-1 structural engineers X-rayed the stabilizers
and used bore scopes to peer through fastener holes to find the
cracks, which were discovered in almost every B-1. Engineers devised
a temporary repair plan to keep the bombers flying until a permanent
repair method could be developed.
The permanent repair calls for removing
the horizontal substructure and replacing it with a beefier substructure.
Full production of the stabilizers is expected to start in the
next two months.
Contact military writer Sidney Schuhmann
at 676-6721 or schuhmanns@abinews.com
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Copyright
©2001, Abilene Reporter-News / Texnews / E.W. Scripps.
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