General Electric is to begin production of the YT706 turboshaft engine to power US Army special-operations Sikorsky MH-60M helicopters after completing key development ground and flight tests.

The YT706-700 is a growth version of GE Aviation's commercial CT7-8 turboshaft and produces 2,600shp (1,940kW) compared with 2,000shp for the T700-701D that powers the standard UH-60M Black Hawk utility helicopter.

GE won a competition in 2005 to supply 120 engines to power special-forces MH-60Ms, which need increased hot-and-high capability, says programme manager John Martin. Deliveries will begin next year.

Compared with the -701D, the YT706 has a 25% larger compressor, full-authority digital engine control and improved turbine cooling and materials. Development included 40h flying in an MH-60M test aircraft.

Changes from the commercial CT7-8A include revised "fail fixed" controls that ensure the engine maintains power if both FADEC channels fail. The CT7-8 shuts down if there is a dual failure, says Martin.

With the commercial designation CT7-8B5, the engine belongs to the family powering the Sikorsky S-92 (-8A) and Lockheed Martin/AgustaWestland VH-71 (-8E). The -8F5 has been selected to power Spain's NH Industries NH90s, and the 3,000shp -8C is under development to power later VH-71s. Also under development is a FADEC-equipped T700-701E to power the upgraded, fly-by-wire version of the UH-60M.

Source: Flight International