Depot liaison engineer keep AFCENT aircraft flying safely

Published Sept. 19, 2013
By Master Sgt. Marelise Wood
386th Air Expeditionary Wing Public Affairs

SOUTHWEST ASIA -- When one's car has a mechanical failure, the operator's manual is an immediate source of information. It may reveal a solution to the problem or highlight the need for a mechanic. But what if you fly, not drive, and your aircraft breaks down with a problem that the 'aircraft manual' doesn't cover, then what do you do?

1st Lt. Eric Yerly is an aeronautical engineer deployed to the 386th Expeditionary Maintenance Group, undisclosed location, Southwest Asia. He grew up as the son of a fighter pilot and wasn't as interested in the inner workings of airplanes as he was flying them. Lucky for the Air Force, his career goals changed when he went to college.

"Since I was about 5 or 6 I wanted to fly," said Yerly. "Boys always want to do what their dads do. As I got older, when I got into college I started my engineering degree. I found I enjoyed engineering more than the flying aspect."

Yerly didn't become just any engineer. He's an aircraft battle damage and repair engineer who instructs other engineers on assessing damage, engineering repairs, and hands-on repairs. He's also a depot liaison engineer (DLE) who aircraft mechanics call when they have a problem that their technical orders (TOs) don't cover. Those requests are called technical assistance requests or TARs.

Yerly's home unit is the Air Force Life Cycle Management Center at Robins Air Force Base, Ga. The center houses the Tactical Airlift Division which addresses C-130 TARs Air Force wide.

"A unit submits a technical assistance request to engineering," said Yerly. "I specifically take care of structures. It could just be a question about tech data, it may be about physical damage, but we answer all those questions. We either perform the appropriate engineering that's required or we do the research and come up with an answer for them. We go above and beyond what's written in their books."

The maintainers' "books" or TOs are equivalent to churchgoers' bibles. They lay out specifically what is needed to maintain the aircraft and following the instructions down to the smallest rivet, is paramount.

"One eighth of an inch doesn't sound like a lot right," said Yerly. "But 1/8 of an inch to a 3/32 rivet is a lot. The thickness of a part, its size, what it's made out of, how it's installed...all those things play into the safety of the airplane. So if you install a rivet and you don't squeeze it fully, it doesn't fill the hole all the way, so it vibrates a little bit. Well the vibration over time creates a crack which causes the rivet to fall out which makes the two pieces that it was holding together loose. You lose one rivet and you don't have a large enough, what we call margin of safety, it can actually cause all the other rivets to fail and it can actually cause the aircraft to crash."

With consequences like that, it's clear why aircraft maintainers don't stray from what's in the TOs. So when an issue comes up that the TO doesn't cover, having Yerly around can be time-saving and life-saving.

"The biggest thing is that it saves so much time and money," said Lt. Col. Elizabeth Clay, 386 EMXG deputy commander. "There are some jobs where my guys end up at a standstill because that particular repair is not in the book. Nose to tail, if there's anything on these aircraft that my mechanics can't fix, he's the one that steps in and provides advice and guidance."

While Yerly is housed at the 386th Air Expeditionary Wing and the maintenance group gets to reap the benefits of having him on station, he is an Air Force Central Command asset. He is currently one of four DLEs deployed to the area of responsibility responsible for the safety of flight for all AFCENT's aircraft. In addition, of the four, he is the only one who specializes in C-130s and since being here, he has responded to cracked aircraft doors, flown to remote locations to help fix aircraft, been shot at helping to cannibalize one, and even seen one blown up.

"It's hard to see an airplane that you really enjoy working on get destroyed," said Yerly.

The aircraft in question was damaged beyond economical repair following an aborted landing. The determination was made that the aircraft could not be fixed and saved, so the usable parts had to be salvaged.

"I was the first person on scene," said Yerly. "We were able to save over $20 million in parts. It was thirteen guys, including myself, and we were able to still perform our mission despite being mortared. Those are things that nobody teaches you."

In another location, Yerly was able to assist with the repair of 12 aircraft and ultimately saved one mission.

"We got out there, did our assessments and evaluations we are trained to do and we saved them about 1,200 hours [of repair time]," said Yerly. "We worked on 12 airplanes and got one mission out."

Yerly prides himself on coming up with solutions and making life easier for the people with whom he works.

"It's my job to either find a way to come up with a repair or a solution based off what we have or to come up with the fastest possible means to alleviate whatever issue they have," he said.

The C-130 maintainers here at the 386 EMXG are especially grateful.

"A lot of times you just don't have the guidance, it's not provided, or you know what you want to do but you want to make it official, and that's where TAR comes in," said Chief Master Sgt. Phillip Tavenier, Aircraft Maintenance Unit superintendent, deployed from the 107th Airlift Wing, Niagara Falls, N.Y. "They [TARs] usually go back to field engineering, and Yerly' s connected, that's his job, and not only is he connected, but he's connected by airframe, he's a C-130 engineer. He understands metal heat treating, he understands what an engineer would need to understand, and that just makes our job easier and gives us the guidance we need to get that job in the right direction the first time without guessing."

Yerly's world is not one of "guesstimations." He takes measurements, makes calculations and comes to solutions based on the numbers, all while doing what he loves.

"I really love just getting to work with the airplanes and work with the maintainers specifically," he said. "As officers, they always tell you 'you're here to remove roadblocks,' well this is my way of removing roadblocks for them and it really is gratifying knowing that I'm putting an airplane back in the air that otherwise would just sit there."