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Tinker team molds, installs metal for hobbled Ellsworth B-1B bomber

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  • By Howdy Stout
  • Tinker Public Affairs
TINKER AIR FORCE BASE, Okla., --  A team of bomber repair experts from the 76th Aircraft Maintenance Group are at Ellsworth Air Force Base, S.D., with custom-made parts to undertake one of the more complicated B-1B repair projects in recent history.

The special repair mission is the result of a faulty maintenance stand that fell, puncturing and gashing a portion of the supersonic bomber's fuselage and fuel tank. The size and extent of the damage meant repairing the aircraft in place with custom-made sections of aircraft skin manufactured at Tinker.

"It was such a team project," said Glenn Berglan, flight chief of the 551st Commodities Maintenance Squadron. "It went well."

Although crews are often dispatched to repair aircraft in place, this is the first time that complex, compound sections of B-1 aircraft skin of this size have been manufactured at Tinker for a repair job. Workers from the 551st Commodities Maintenance Squadron sheet metal shop had to create their own manufacturing jigs and forms to shape the one-eighth-inch-thick aluminum. No original manufacturing jigs still exist.

"What we came up with was just a gauge type tool to make sure we had the right shape and contour," explained Mr. Berglan. "It was designed by tool design engineer Todd Bayless. Then we got the best sheet metal mechanics we could, Robert McCarty, Glenn Haley, and Thomas Seitz to manufacture the skins and doublers."

Designed to fly low-level, at supersonic speeds, the B-1 has a thicker skin than traditional aircraft. In addition, the skin of the aircraft also bears part of the load of the entire aircraft structure, contributing to its overall strength.

"It's built like a big fighter," said David Mason, a unit supervisor for the sheet metal shop that manufactured the sections.

That strength, combined with the complex compound curvatures of the skin, meant a tough job for the sheet metal workers. Mr. Mason said they used up to 60 tons of pressure on one of the machines just to get the proper shape in the aluminum.

"It gave us that initial twist that we couldn't do by hand," Mr. Mason said. "This aluminum is very thick. It's not just sheet metal."

"That was the biggest challenge, making the parts," said Tech. Sergeant William Chapin, team chief of the on-site repair crew. "They stamped out a whole skin for us to cut out the repair patch so it will match the curvature perfectly." Project engineers Ryan Rowten and John Morgan, along with and members of the repair team, helped oversee the skin manufacturing process. The double-contour skin section required a week to manufacture using specifications provided by engineers. Two identical sections were manufactured.

The second section was manufactured to provide a set of doublers -- a second, internal layer of skin -- to help brace the outer skin. Both hand-crafted skin sections had to be identical.

"This repair, we had to be dead-on, otherwise it wouldn't fit," Mr. Mason explained.

Crews are expected to replace several sections of aircraft skin on the forward fuselage between the cockpit and left wing. The manufactured sections are relatively large, measuring 73 inches by 48 inches.

"They wanted a big enough piece that they could cut and lay in," said Mr. Mason.

Mr. Berglan said engineers, aircraft mechanics and sheet metal workers met almost daily during the manufacturing of the skin.

"I think it was extremely helpful that the two sergeants (making the repairs) were here and know what we had done," he said.

Manufacturing two complete sections of skin without existing jigs or forms required a higher level of creativity than normal for aircraft sheet metal work, Mr. Mason said.

"I had to bring in mechanics who were also artists," Mr. Mason said. "It was very tough and very stressful. They had to think really way outside of the box. They earned their pay on this one."

Compounding the repair effort is the fact that the skin section itself forms part of the overall structural strength of the aircraft. The aircraft will be jacked up off its undercarriage and braced to minimize the load on the section of skin to be repaired, said Ryan Rowten, the project engineer overseeing the repair effort.

"That complicates it a little bit. It's a fairly daunting task," said Mr. Rowten.

The faulty maintenance lift also punctured a fuel tank. That, too, must be patched with doublers and sealed for pressurization and leaks. If everything goes according to plan, the work is expected to take four weeks.

"But sometimes when you take the plane apart there is more damage that you can see," said Sergeant Chapin.

"Once the team gets up there it's not 100 percent certain that they won't have to come back to the sheet metal shop," said Barbara Alexander, production management specialist for the 553rd.

"Until that airplane is in the air, it's not finished," Mr. Mason said. "We're on standby."

Sending repair teams from Tinker to fix B-1s at outlying air bases is becoming increasingly common as the demands on the strategic bomber are high since the advent of the War on Terrorism. The aircraft are often on-call and the tempo of operations means increased wear and operational damage.

"We've sent teams to Forward Operating Locations and Guam, Dyess and Ellsworth," explained Ms. Alexander.

"It's what we do," said Sergeant Chapin. "It's our job to go fix planes at other places."

Depending on the work to be done, experts from various fields are assembled and dispatched. In this case, Sergeant Chapin said, trainees joined the team for first-hand experience in battle-field-like repair work.

"This isn't something that happens every day," he said.

In fact, Mr. Rowten said, most maintenance is scheduled, giving those utilizing the B-1 an opportunity to plan on having a set number of aircraft available for operations. That's why when unexpected damage to an aircraft occurs, it is essential that crews work quickly to get the aircraft back in service.

"Availability is a critical thing," Mr. Rowten said. "It's critical we get these airplanes up and running. They're flying a lot of sorties with these jets right now."

Mr. Mason credits fellow unit supervisor Joe Goodwin for the quick manufacturing process.

"If it wasn't for him, we couldn't have done it as fast," Mr. Mason said.

Crews, their tools and custom-made parts convoyed to Ellsworth on March 21st to begin repair work. Once done, the aircraft will be returned to service.

"We'll do some operational checks on the plane and then it'll be good to go," said Sergeant Chapin.