SOUTH CHINA SEA — The jet bay never really sleeps. Tools clink against engine rails, and the smell of oil hangs heavy in the air as mechanics gather around an engine that has already flown thousands of miles, but still has many more ahead of it. In this space below the flight deck, the jet engine shop works to make sure the roar above never stops.
U.S. Navy Sailors assigned to the Aircraft Intermediate Maintenance Department 2nd Division (IM-2) aboard Nimitz-class aircraft carrier USS Abraham Lincoln (CVN 72) are responsible for breaking down, rebuilding, inspecting and testing the jet engines that power the carrier air wing.
“Our primary focus is to produce ready-for-use engines, modules, parts, and support equipment for flight operations,” said U.S. Navy Aviation Machinist’s Mate 2nd Class Ikaika Leialoha, leading petty officer of IM-2. “Everything we do supports flight operations.”
IM-2 serves as the ship’s intermediate-level maintenance activity, bridging the gap between squadron-level maintenance and the larger supply system onboard. The shop’s mechanics work with F414-GE-400 engines, providing in-depth inspections and repairs that fixed-wing squadrons aboard the ship cannot perform. The engines weigh approximately 2,500 lbs., and produce approximately 21,900 lbs. of thrust.
“The primary rate that works in our shop is aviation machinist’s mate,” Leialoha said. “But what really makes the shop run are our Collateral Duty Inspectors (CDIs).”
Those inspectors are qualified to inspect, operate and test engines at various stages of maintenance. Each CDI carries specific responsibilities, from operating and testing the engines, to breaking down and building the engine back up.
Teamwork has been critical during Lincoln’s 2025-2026 Western Pacific deployment. In less than 30 days at sea, the shop produced three ready-for-issue engines.
“That’s not typical,” Leialoha said. “Usually, you might see two or three a month later in deployment.”
For the Sailors of IM-2, the pace can be relentless. Multiple engines arriving at once means longer hours, crowded and hot workspaces, and heightened stress.
“This accomplishment was made by each and every Sailor that works in my work center,” said Leialoha. “Without those people, we wouldn’t get the job done, especially our CDIs.”
Returning an engine to service begins when it arrives from a squadron with a discrepancy. Depending on the issue, that engine may require anything from limited repairs to a full teardown.
“That means breaking down and inspecting every single component,” said Leialoha. “That includes anything from little accessories, lines, brackets and gaskets to your bigger components like the fan and afterburner. You have to know your stuff, because you’re signing your name on it.”
Once rebuilt, a team conducts tests and checks on the engine on the fantail. A mechanic operates the engine inside a test cell room, using a Jet Engine Test Instrumentation computer (JETI), simulating real-world conditions.
The team includes a mechanic who supplies an air source to the engine using a Mobile air Start Unit (MSU), a trouble shooter who diagnoses and resolves malfunctions on the engine, a JETI operator, a window watcher who facilitates communication between the JETI operator and the trouble shooter, and a scribe who records information from the test.
The engine test run lasts anywhere from three to eight hours. Only after a successful test run, IM-2 deems the engine ready-for-issue.
For U.S. Navy Aviation Machinist’s Mate 3rd Class Darren Tang, an IM-2 mechanic and CDI, that moment never gets old.
“The most rewarding part is troubleshooting an engine on the fantail, fixing it and then seeing it sent back to a squadron,” Tang said.
For Leialoha, working with engines in IM-2 carries a unique weight.
“This isn’t like fixing your cabinets in your house,” said Leialoha. “This is bigger than that. It’s a special feeling when you know what you worked on is flying again and supporting the mission.”
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