T-55 engine

The U.S. Army awarded Honeywell International a $249 million contract to maintain and overhaul the T-55 turboshaft engines powering the CH-47 Chinook helicopter fleet, the Department of War announced. The three-year contract, running through May 2029, covers depot-level maintenance and overhaul work to keep the Army's Chinook engines operational and prevent any gap in the supply of serviceable powerplants. Army Contracting Command at Redstone Arsenal in Alabama issued the contract with specific work locations and funding to be determined order by order as requirements arise. The T-55 is one of the longest-running military engine programs in American history. Honeywell, based in Phoenix, Arizona, has been building and supporting the engine since the 1950s, when it was designed by Lycoming Engines as a scaled-up version of the smaller T-53. Since its first delivery to the U.S. Army in 1961, when it produced 2,200 shaft horsepower for the original CH-47A, the engine has been progressively upgraded through multiple generations. The current production variant, the T55-GA-714A, produces nearly 5,000 shaft horsepower, enabling the Chinook to carry up to 26,000 pounds of cargo externally or move up to 55 combat-equipped troops at speeds reaching 170 knots. More than 6,000 T-55 engines have been built and the type has accumulated approximately 12 million flight hours on CH-47 and MH-47 special operations variants. That is a remarkable service record for an engine whose basic design predates the Beatles. The Chinook itself is the Army's primary heavy-lift helicopter, a tandem-rotor design that has been in continuous production since 1962 and has proven durable enough that the Army is still buying new CH-47F Block II variants today. The tandem-rotor configuration, with one rotor at the front and one at the rear of the fuselage, eliminates the need for a tail rotor and gives the aircraft exceptional stability when carrying heavy or awkward slung loads, a characteristic that makes it the platform of choice for moving artillery pieces, vehicles, and large quantities of fuel and ammunition in forward areas. Special operations forces fly a dedicated variant, the MH-47G, fitted with additional avionics, terrain-following radar, and aerial refueling capability for long-range clandestine missions. The Boeing facility at Ridley Park, Pennsylvania, serves as the primary production and modification center for the Chinook family. Depot-level maintenance is the heaviest category of military aircraft maintenance, involving complete disassembly, inspection, repair, and reassembly of major components, in this case the engines, by specialized technicians at industrial facilities rather than at forward operating locations. An engine entering depot maintenance is typically at or near the end of its allowable service life between overhauls, and the overhaul process restores it to a serviceable condition equivalent to new. For a fleet as large and as continuously operational as the Army's Chinook force, maintaining a steady flow of overhauled engines through the depot pipeline is not a logistics nicety but a direct readiness requirement. When the contract announcement explicitly cited the need to "prevent a gap in maintenance and overhaul supply," it was describing the practical consequence of any interruption: helicopters sitting on flight lines without serviceable engines, missions that cannot be flown, and units unable to move the people and equipment the ground force needs.

T-55 engine

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T-55 engine

U.S. Army awards Honeywell $249M to maintain Chinook engines

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About The Defence Blog