The US Air Force will seek innovative approaches for re-engineing additional Boeing 707-derivative aircraft which are now equipped with Pratt & Whitney TF33 turbofan engines.

The study contracts, which will be awarded once funds have been identified, are expected to go to Boeing, which initiated the re-engineing debate with an unsolicited bid to put leased engines on the Boeing B-52H, as well as Pratt & Whitney, CFM International and Rolls-Royce/Allison.

Consideration of a broader re-engineing programme comes as Boeing and USAF officials attempt to reach agreement on cost-savings claimed by Boeing.

The scheme involves re-engineing up to 71 B-52H strategic bombers. Four R-R RB.211-535E-4 turbofans, each of 192kN (43,000lb)-thrust, would replace the aircraft's eight twin-podded 75kN TF33s.

Boeing and R-R/Allison could profit additionally from USAF interest in expanding the re-engineing effort to as many as 179 other aircraft derived from the four-engined Boeing 707, including the E-3 Airborne Warning and Control System (AWACS), the E-8 Joint Surveillance Target Attack Radar System(JSTARS) and the RC-135 Rivet Joint, which are TF33-powered.

The B-52H and militarised 707 engine leases are expected to be separate projects because the RB.211 is too powerful for the latter aircraft. The 82kN BMW Rolls-Royce BR715 is viewed as a likely candidate.

The E-8 is being offered to NATO to meet a European requirement for a stand-off surveillance capability, with the BMW R-R engines also being proposed. ANATOE-8 unit would operate along similar lines to its E-3 AWACS squadron.

Source: Flight International