Graham Warwick/WASHINGTON DC

The US Navy hoped to gain clearance to order additional Boeing F/A-18E/Fs after briefing US Department of Defense officials last week on its solution to the manoeuvre wing-drop problem. A porous wing-fold fairing has been demonstrated to eliminate the problem, a Navy official says.

US defence secretary William Cohen had blocked release of funding for a second low-rate initial production batch of 20 aircraft until the wing-drop problem was solved. After extensive flight tests, solutions including extended leading-edge snags, grit tape and stall strips were dropped in favour of a "variable porosity" wing-fold fairing. Weight, performance and signature penalties are believed to be minimal, with range still exceeding the specification.

Boeing, meanwhile, has moved to counter further criticism of the F/A-18E/F by the US General Accounting Office (GAO). The Congressional watchdog, in a new report, cites development problems with the aircraft's tails, stealth features, weapons and engines.


Boeing hopes its wing solution will clear the deck for further F-18E/F orders

Boeing says a solution to delamination of the horizontal stabilisers will be in place for the second low-rate production batch. Structural changes to the vertical stabilisers are in place for the first production batch, the company says. Stealth anomalies have been tackled by changing vendors, Boeing says, adding that weapon separation issues have been overcome by toeing in the pylons and changing the bomb release interval.

General Electric acknowledges that some development issues remain with the F414 engine, including weight increases and "pop stalls" during start-up. The stalls are being tackled by rescheduling the full authority digital engine control and by studying possible seal changes.

The engine remains some 6.5kg overweight, partly because of redesign following a containment failure in a fan blade-off test, but further reductions are planned. Qualification of the engine for full-rate production has been scheduled for August, but will be "tight", GE admits.

Source: Flight International