Another accident, involving a USAFE F-16CG of the 31st FW may have something in common with the near accident of the British Airways 038 at London Heathrow last week. As previously reported, one of the possible root causes of the engines failure that compelled the B.777 G-YMMM to a successful crash landing could be the corruption of the pressure sensors signals received by the engine control systems. Noteworthy, something similar was one of the contributing factors that on September 18th, 2007, caused the loss of an F-16CG of the USAFE. According to European edition of Stars and Stripes, the recently issued Air Force report, in addition to weather and human factors, blames a malfunction of the Air Data Computer (ADC) of the Aviano based F-16. “According to the report, a drip ring in the device that tells the aircraft its trajectory froze as the plane flew through thunderstorms over the base. The result was that plane computers continued to receive the same information, even as it climbed in altitude and lost air speed. The incorrect information also fooled the sophisticated aircraft from correcting itself in time to prevent an uncontrolled spin”. The report underlines also that the same problem with the ring has been a contributing factor to other three F-16 crashes and for this reason it is going to be redesigned. It is still too early to say if the FADEC of BA038 was really confused by the signals coming from some sensors, however, the Aviano accident surfaces a problem: on-board systems (either Air Data Computer, Autopilot, Autothrottle, etc), despite working properly, can be deceived by corrupted signals. Since most of modern aircraft are platforms in which avionics, communications, navigation and targeting are based on calculations provided by powerful computers, this kind of problem should let you to think also to the “network” that interconnects those computers to the sensors that feed them. Even if carrying enough processing and storage capability is important, ensuring the availability and the integrity of the data that travel in the network is paramount. For sure, data must travel from source to destination without being compromised. What has to be investigated more is if a corruption of the signals can occur when a mobile phone is switched on during the approach.
