'This is depot work - this is what this base was meant to do'

by Jenny Gordon
78th Air Base Wing Public Affairs

8/21/2015 - ROBINS AIR FORCE BASE, Ga. -- Heavy structural repairs occur every single day at the Warner Robins Air Logistics Complex, yet one in particular has received some extra attention during the last few months.

As an F-15C was moving early on through programmed depot maintenance in the 561st Aircraft Maintenance Squadron, a vertical crack measuring about 7 inches was discovered along one section of the fighter jet's bulkhead.

This particular aircraft had been previously inspected in the field using an ultrasonic testing technique (nondestructive inspection); however, when the aircraft arrived on station the crack that was detected earlier this summer was larger than anticipated. Lab testing will continue to further investigate.

After consultations with system program office engineers, the options were to either replace this particular bulkhead or scrap the entire plane.

"You can't use an airplane if that crack gets too big," said Dave Currie, an F-15 aerospace engineer. 

Remove and Replace

An expensive part to purchase and replace, the decision was made to replace the 626 bulkhead through the Defense Logistics Agency supply chain. The 626 bulkhead sits near the rear of the aircraft and center fuselage. It's a significant structural component that takes a lot of wear and tear during flight, and connects several critical pieces of the aircraft, including the wings and engines.

Planning began and procedures were set in motion to figure out how to accomplish this first-ever repair process. It was pulled out of regular maintenance into an unscheduled depot level maintenance gate for additional work. Once the work is completed, it will continue through PDM.

With the replacement bulkhead originating from an E model, there would be a learning curve when it came time to separate the aircraft's existing cracked bulkhead, and install a new one.

But in order to remove the bulkhead, the aircraft had to be split in half.

"The most challenging part involved removing the fasteners that were inside the center fuselage," said Dennis Pickett, 561 AMXS aircraft structural repair mechanic. "They were hard to get to and knock out. You get pretty scratched up doing it."

The entire process from disassembly of the aircraft to installing the new bulkhead took seven weeks which was on schedule. Special tooling was required to drill the wing lugs which delayed the project five weeks. However, work resumed early this month and was completed Aug. 8. The aircraft now moves into the reassembly phase with estimated completion on Aug. 24.

Pickett estimates that once it came time to reinstall the bulkhead, 500 to 600 fasteners were tediously and carefully re-attached to marry the two sections. Everything had to be perfectly in place during assembly; no single hole alignment can be off.

"What we tried to do once it was taken off is put it back in the same position it was in, if not better," he said. "It'll be a better plane going out than coming in.

"This is very tedious work that needs to be done right," Pickett added. "This bulkhead is carrying a lot of stress and a lot of weight -- there's no room for error. You make one error, and you don't get another bulkhead."

Staff Sgt. Glynn McDaniel, 402nd Expeditionary Maintenance aircraft battle damage repair technician, spends a lot of time travelling to locations to repair aircraft. He said this opportunity afforded him good training, learning different techniques along the way.

"The most stressful thing about taking it apart was accounting for every single small piece you took off," he said. "You keep everything because you never know what you can't have, can't find or can't order later on." 

McDaniel said the work was educational.

"There's so much to learn," he said. "As far as structural repair, this is it right here. It doesn't get any heavier than this." 

More than just a job

The core team is quick to point out that success of the bulkhead replacement didn't involve just a single shop. Everyone from DLA to NDI to the 402nd Commodities Maintenance Group and 402 EDMX played an essential part.

"I think the next time this happens we'll be ready," said Rick Weeks, 561 AMXS flight chief. "We know the tooling we need, how things should flow and all the players we need."

Pickett, who has been at Robins for 30 years said it takes more than just showing up to do this kind of work.

"I tell everyone that it's all about experience, knowledge and dedication. If you don't have dedication to this job, you'll never get it done. This is a reflection on you. Work together, and we'll get the job done," he said.

"F-15s, C-130s have their heavy load, C-5s and C-17s -- all have certain jobs that they can only do at Robins Air Force Base," he said. "This is depot work -- this is what this base was meant to do."