jon@june.cs.washington.edu (Jon Jacky) (06/24/89)
From: jon@june.cs.washington.edu (Jon Jacky) Here are excerpts from AVIATION WEEK AND SPACE TECHNOLOGY, March 6, 1989: ``One Digital Computer to Replace Six Flight Control Units in F-111'' by William B. Scott The F-111 figher/bomber flight control system is being upgraded with a single digital computer that will replace six analog line replaceable units. The modifications are expected to improve fleet-wide safety records of the Air Force/General Dynamics F-111, which has a history of flight control and terrain following radar interface problems, according to USAF officials. The current program was prompted by Tactical Air Command and Strategic Air Command safety concerns, as well as a desire to improve the system's reliability and maintainability. ... Other modifications under the same program include ... adding a voice warning system to alert flight crews of control system anomalies and potential ground collision ... all annunciator warnings require pilot action to change the aircraft's flight path. There are no interfaces with the flight control system to trigger an automatic fly-up response, for example... The new digital flight control configuration is designed to provide the same handling qualities as today's operational F-111's. To ensure updated aircraft handle the same way, much of the planned flight testing will repeat ... evaluations ... performed in the 1960's. ... ``We could use more modern test techniques, but we want to duplicate what they did [in the 1960's],'' Maj. Tom Humes, F-111 combined test force director, said... Although the latest flight control changes will help extend the aircraft's useful life, Air Force officials note that improved safety was the primary consideration in launching the current program. ``The bottom line is that we expect to save people's lives --- and save a few more airplanes, too,'' Humes said. [ The article implies, but does not say, that there have been fatal F-111 crashes involving the analog flight controls and terrain-following radar ] - Jon Jacky, University of Washington