Strategy review prompts shift of focus from increasing range to improving efficiency and reducing operating costs

Boeing is refocusing its 767-300X studies on "mission-specific" changes for improved efficiency and lower operating costs instead of increased range. It says airlines are showing interest in an unusual development plan hinging on an interchangeable wingtip.

The shift in emphasis follows a strategy review after 11 September, with input from existing 767 customers, along with Boeing's decision to focus near-term proposals on existing niches.

The company says efforts to develop a longer range 767-400ER to compete head-on with the Airbus A330-200 are "on the back burner" given market uncertainties and the lack of a suitable engine.

Key to the revised -300X is a version of the raked wingtip developed for the -400ER. Unlike earlier proposals, however, the -300X is being studied with optional wingtip kits that can be swapped by the airline to tailor the aircraft for certain routes and make it "mission specific". Under the plan a virtually identical version of the -400 raked tip would be installed for short- to medium-range routes up to around 5,550km (3,000nm). For longer-range missions, however, the raked tip would be replaced with a smaller raked unit, or the standard "close-out" tip.

Although apparently counter-intuitive, given the acknowledged benefit of raked tips and winglets on longer flights, Boeing says the plan would give 767-300 operators the efficiency benefit of the new device without "having to carry around extra weight".

"A lot of airlines are showing interest, particularly in Europe where they can be used on shorter routes," says 767 chief project engineer Peter Weertman, who adds the tip change could be made in as little as 30min.

Aircraft can be dispatched without the 2.1m- (6.9ft) long tips, but payloads are reduced between 4,360kg (9,600lb) and 5,680kg as a result, says Weertman. The devices, which weigh around 67kg apiece, are expected to generate around a 2% saving on routes as short as 2,775km, says Boeing.

The raked tip would be replaced for longer-range missions to avoid exceeding wing-load limits with full fuel at take-off. Previous -300X studies mainly envisioned a heavier, longer-range aircraft with additional fuel capacity and the beefed-up wing of the -400ER.

According to Boeing's figures taken from Continental Airlines and Delta Air Lines 767-400ER operational data, these indicate a fuel-mileage benefit of up to 5.5% in cruise, or a 4.7% block fuel saving over a 5,550km route.

Kawasaki Heavy Industries (KHI) is to manufacture composite blended winglets for retrofit to Boeing 737 Classics (-300/400/500) after winning a contract from Aviation Partners Boeing (APB). The first pair are due to be delivered in June. "We are expecting to manufacture around 550 shipsets including options," says KHI. APB is to conduct certification flight tests of the blended winglets on a 737-300 this year. It claims a reduction in fuel burn of 6-7% and expects "over 60%" of 737 Classics to be equipped with the winglets.

Source: Flight International