A "transonic clean-up" is under way on the Boeing F/A-18E/F to reduce the performance penalties associated with the solution devised for the earlier wing drop problem.

The porous wing fold fairing which eliminated the manoeuvre wing drop has increased drag, which has reduced range and acceleration marginally. While the single-seat F/A-18E still exceeds its range specifications, the two-seat F/A-18F now falls slightly short of its interdiction range target, the US Navy acknowledges.

Efforts also continue to reduce the "residual lateral activity" that remains after elimination of the wing drop. The navy describes this as "small twitches in the extremes of the envelope", and says similar characteristics are exhibited by the current F/A-18C/D.

Recently completed operational testing of the F/A-18E/F confirmed that wing drop no longer exists, says the navy. Unusually, their report has been classified, but the navy says testers found the aircraft to be "potentially operationally effective and potentially operationally suitable" and recommended continued development. The navy says the report concludes that "...the positive attributes demonstrated by the aircraft outweigh the negative impacts in all critical operational issues".

Several issues were raised which the navy hopes to cure before full operational evaluation begins in May. These include the residual lateral activity, buffet and drag resulting from the wingdrop fix; and potential concerns about the impact of noise and vibration on the service life of wingtip-mounted AIM-9 missiles. The service acknowledges that the larger E/F does not match the current C/Din all performance areas, notably acceleration, but says the E/F "-is a different aircraft tactically. We will develop new tactics around the capabilites of the aircraft."

The navy says the E/F has higher pitch pointing accuracy and better departure resistance, which improve air combat capability. In 75% of engagements against F--14s, F-16s, F/A-18As and F/A-18Cs "...the F-18E got in the first shot", it says.

Source: Flight International