LOCKHEED HAS selected General Electric's CF6-80C2 turbofan to power the C-5D, an improved version of the Galaxy which will be offered for the US Air Force's non-developmental airlift aircraft (NDAA) requirement.

The NDAA is an alternative to the McDonnell Douglas C-17 and will only be purchased if the US Department of Defense (DoD) decides in November not to buy more than 40 C-17s.

Lockheed is the only competitor for the military portion of the NDAA and will respond to a final request for information by the end of April, says C-5 programme director Bill Arndt. Commercial bidders are expecting a final request for proposals (RFP) at the end of this month, with bids due within 60 days. Boeing will offer the 747-400F freighter.

Arndt says that the major changes from the present C-5B are the new engines and digital avionics. Lockheed is proposing the avionics architecture developed for the C-130J Hercules 2, using the same hardware and 60% of the software.

Equipment includes Lockheed-Sanders mission computers, flat panel displays and the Honeywell digital autopilot.

The C-5's 191kN (43,000lb)-thrust GE TF3s will be replaced with 222kN CF6-80C2s flat-rated to 35.5¡C, improving the Galaxy's hot-day take-off performance and initial cruising altitude, Arndt says. Reliability will be substantially improved, but the commercial CF6's higher weight would offset its fuel-consumption advantage over the older TF3, he says. The CF6 was originally derived from the TF39.

Boeing has selected Pratt & Whitney's PW4056 for the NDAA 747-400F. The company says that the first aircraft could be available within 18 months of a go-ahead, while Lockheed says that it could fly for the first C-5D within 37 months.

The number of NDAAs, required will be determined, by an airlift study now under way and the number of C-17s eventually acquired. Arndt says that Lockheed is basing its costs on 50 aircraft.

McDonnell Douglas is confident that the US Air Force will receive all 120 C-17s planned and is undecided how to respond to the NDAA RFP. Plans to offer a commercial "MD-17" have been dropped and the MD-11F is its only alternative.

A "mini" readiness review is under way, involving one week's high-temperature flying of six in-service C-17s, in preparation for a month-long review planned for July to provide data for the DoD decision.

Source: Flight International