Maintainers make historic engine removal

Published March 10, 2010
By Senior Airman Abigail Klein
22nd Air Refueling Wing Public Affairs

MCCONNELL AIR FORCE BASE, Kan. -- After 26 years of service, the first KC-135R Stratotanker F108-100 engine delivered to the Air Force in the United States made its last flight at McConnell Air Force Base, Kan., March 1.

When KC1-35R tanker engines were originally purchased from CFM International, it marked the first time in history the U.S. military had bought a commercial engine for its aircraft. Upon purchase, the engine model, CFM56-2B, was designated as the F108 model by the Air Force.

Like the other F108 models, the engine from McConnell will be refurbished and returned to service.

Before being removed, the engine was used March 1 in two refueling missions. While preparing the aircraft for a third refueling mission, Airmen from the 22nd Aircraft Maintenance Squadron noticed the blades on the engines turbo fan were unlatched at three positions around the rotor.

"With some difficulty, the blades were re-latched and an engine run was accomplished, after which the blades were observed to be un-latched again," said Brad Mehlinger, CFM International Filed Service Engineer. "This is not considered abnormal on engines with high operating hours."

He said the maintainers attempted to latch the blades again, but were not successful.

"After two hours ... we determined that the engine required removal," said Tech. Sgt. Jake Salinas, 22nd AMXS engine mechanic.

The KC-135 has four engines, model F108 was the outer engine on the left side of the aircraft.

During its 26-year career, the engine accumulated 13,409 hours of flight.

"This engine was hanging tough until this happened," said Mr. Mehlinger,. "Even after more than 26 years in service, this engine was not due for scheduled maintenance for another two or three years."

The 8,000 pound engine was removed March 3, by four members of the 22nd AMXS. It took the maintenance Airmen 24 hours to remove the engine and wrap it before sending it to the 76th Propulsion Maintenance Group at Tinker Air Force Base, Okla.

At Tinker AFB, the 76th PMG workforce will disassemble, inspect, repair, re-assemble and perform diagnostic testing on the engine and its parts before it takes flight again, a process that can last approximately six to eight months.

The decision for removal halted not only a long history for this CFM56-2B/F108 engine, but for "R" model tankers in the U.S. Air Force.

"This engine was the first to be delivered to the Air Force in the United States, and it's the last remaining original R model," said Cap. Jacob Sullivan, officer in charge of the 22nd AMXS Green Aircraft Maintenance Unit. "It was impressive that it ran this long without repair, but everything wears out eventually."

Air Mobility Command manages an inventory of more than 415 Stratotankers, of which the Air Force Reserve and Air National Guard fly 235 in support of AMC's mission.

With 63 KC-135R/T Stratotankers on the flightline, McConnell operates and maintains the world's largest and most diverse fleet conducting worldwide military operations.