Nine B-52 bombers sit side by side in the enormous hangar. Surrounded by scaffolding and repair crews, the old planes look like dowagers come to town for a makeover. In a way that's just what they are. Every four years or so US Air Force B-52s fly here for a thorough overhaul. Skin is painted, engines checked, and new equipment added to keep the aircraft airborne even though the date originally set for their retirement is long past.
``Avionics get updated, they get adapted to carry cruise missiles, things like that,'' says Mark Van Gilst, an Air Force engineering planning chief. ``The whole process takes four to five months.''
Welcome to the San Antonio Air Logistics Center (ALC), one of the Air Force's five huge maintenance and refurbishment centers in the continental United States. With a budget of more than $16 billion, the San Antonio ALC's job is to keep Air Force planes flying, if not forever, at least as long as possible.
Toward that end ALC employs a variety of high-tech tools intended to make sure planes are structurally sound. Engineers here claim it would be unlikely that an Air Force plane would suffer the sort of failure that caused skin on an Aloha Airlines 737 to blow off in flight last April.
The B-52s in for their checkup are a good example of the scrutiny the San Antonio ALC says it puts planes through. Small sections of fuselage on many of the planes have been painted gray, meaning they are to be cut out and replaced. ``Eddy current'' tests, in which electrical current is used to generate a picture of a piece of metal's soundness, have determined that these patches have microscopic cracks.
On the B-52s ``we're seeing a lot of stress corrosion,'' says Mr. Van Gilst.
The last B-52 rolled off a Boeing production line in 1962, but a plane doesn't have to be that old to develop stress corrosion. At the other end of the ALC maintenance hangar is a C-5 transport, a whale-like plane dating from the early '70s. Resting on jacks, it seems somehow tired. Forward of the wings its fuselage is visibly rippled from the stress of hundreds of hours in the air.
Besides B-52s and C-5s, the San Antonio ALC is the support depot for the ubiquitous C-130 prop transport and T-38 trainers. Other planes in the service inventory go elsewhere - F-16 fighters, for instance, are sent to the Ogden ALC in Utah.
But some F-16 engines get sent to a special building here. The San Antonio ALC also overhauls more than half of the Air Force's jet engines, including the Pratt and Whitney F-100, the powerplant of the F-16.
F-100s are pulled for renewal after they have been pushed to full throttle some 1,800 times, says Col. Carl Portz, chief of the engine division. Parts are then refurbished and minutely inspected to make sure they have no cracks in the making. Shattered engine rotors and bearings are among the most dangerous mechanical problems that fighter pilots can face.
Tiny engine rotor blades, for instance, are checked by hand for wear and imperfections. Many of the rotor inspectors are blind - their acute sense of touch makes up for their lack of eyesight. Rotors are cryogenically frozen, then spun at tremendous speed in testing pits lined with lead brick. Any imperfection, and the frozen rotor shatters, doing frightening damage to the lead shield.
More mundane glitches of the sort that show up on your car are also fixed - with F-100s ``oil leaks can sometimes be a problem,'' says Colonel Portz.
In San Antonio, at least, fixing airplanes is big business. With 20,000 employees, the ALC is perhaps the largest industrial plant in the Southwestern US. Building 375, the hangar that currently contains the B-52s, C-5, plus a smattering of smaller C-130s, is the largest space in the world without central support columns. It's so large they have basketball courts set up in the spaces between planes.
But the San Antonio ALC has some other duties, too. Logisticians at the base keep records on all the Air Force's nuclear ordinance. Along with taking care of mammoth airplanes, the ALC maintains the Air Force's small fleet of boats and ships. It also manages the Department of Defense working dog center.
That's right, dogs.
Logisticians here purchase all the dogs trained in the military for guard and security duty. No poodles allowed - most of the Pentagon's canines are German Shepherds.