A US Defence Acquisition Board (DAB) has given Sikorsky the green light to begin engineering and manufacturing development (EMD) of the UH-60M modernisation under which the US Army plans to remanufacture over 1,200 Black Hawk helicopters from 2004.

"We've been conducting risk reduction since last September and have been looking at a variety of configurations and options," says Mike Cuppernull, UH-60M/X programme manager. "We now have a baseline for EMD. A contract is expected by the end of April."

Sikorsky plans to produce four UH-60M test conversions, with the modification of the first UH-60A airframe due to start towards the end of this year ahead of a 2003 first flight. A UH-60L and a second UH-60A will also be upgraded, while a UH-60Awill be modified to a HH-60M medevac configuration. There will also be a single new-build UH-60M.

Low rate initial production of the first 12 upgraded Black Hawks will start in 2004, followed by a batch of 18. Remanufacturing will build to 60 helicopters a year, with each taking 18 months to complete. The US Army has earmarked 1,217 helicopters for modification - 900 UH-60As and the remainder UH-60Ls.

The UH-60As will receive the 1,340kW (1,800shp) General Electric T700-701 turboshaft and the 2,530kW-rated improved durability gearbox of the UH-60L as part of the upgrade. "Relative to the A it will provide up to 2,000lb [910kg] additional lift" and have "the L's substantially lower support costs," says Cuppernull.

A key to the improved payload-range performance is a new wide-chord main rotor blade, developed for the S-92 with a 400mm (16in) span extension and anhedral tip. The upgraded machines will also be retrofitted with a stronger centre fuselage to give the rebuilt helicopter a 8,000h fatigue life.

The third major element is a digital cockpit based on the UH-60Q, with dual 1553 databuses, two 150mm x 200mm multifunction displays (MFDs), two control display units, cockpit voice and data recorders, and embedded GPS satellite navigation/inertial navigation system.

Litton will supply MFDs for the test machines after which they will be competitively procured. Unlike the navy's troubled SH-60R upgrade, Sikorsky retains integration responsibility.

DAB approval includes a requirement for a further increase in payload-range which will form the basis of the follow-on, but unfunded, UH-60X upgrade. The army plans to convert 255 unmodified Black Hawks to an X-standard after 2010.

Source: Flight International