It’s been a tough year for Airbus on the automation front. First, NTSB was concerned about incidents involving total glass failure. Now comes an incident where a Qantas Airbus 330 cruising in the flight levels over Australia twice decided it had a better idea and plunged off altitude dropping 650 feet the first time and 400 feet again after the pilots returned it to the original altitude.
“The jetliner experienced a glitch in the computer unit that uses sensors to detect the angle of the plane against the airstream,” says Julian Walsh, chief air investigator at the Australian Transport Safety Bureau. “One of the plane’s three units malfunctioned and sent the wrong data to the main flight computers. It is probably unlikely that there will be a recurrence, but obviously we won’t dismiss that.”
I am sounding like a total Luddite to once again remind GA pilots that autopilots and flight management systems are usually benign tools but when they turn on us, however rarely, shock and awe has to replaced quickly with pilot in command thinking. The mutinous gear must be quickly and positively isolated. At this point you are operating in an abnormal situation – not an emergency but degraded. Under the yellow flag (NASCAR terminology) don’t be afraid to ask for ATC assistance as needed. If you’re single pilot in IMC as for vectors to a nearby ILS etc.
At least 40 people were injured in Airbus mishap as they flew about the cabin. That’s why keeping your seat belt fastened at all times is a really good idea both in light and heavy aircraft. Ya just never know when the genie is going to get out of the bottle.