Any smart pilot or organization manager studies Murphy’s Law: life’s wonderful reality that if something can go wrong, it will! There are dozens if not hundreds of corollaries that remind us that complex airplanes are veritable breeding grounds for Murphy mischief.
In the March Issue of AOPA Pilot, I wrote about Air France 447, the Airbus 330 that went down over the south Atlantic after all three pitot tubes froze up. This caused the air data computer to leave the premises, and the automated systems, which the Airbus has raised to an art form, began cascading failures. The crew lost total situational awareness and the junior first officer, after some gyrations, pulled the big ‘bus into a stall and held it there for about three minutes for a final plunge from about 35,000 feet. Lots to learn from this one!
The saga of automation acting out continues. Here are two more incidents involving the Airbus where, once again, frozen pitot tubes discombobulated the autopilot, auto-throttle, and flight director. The crew managed to control the aircraft, but had to divert to an alternate airport because they couldn’t remain in reduced vertical separation maneuvering (RVSM) airspace and fly manually to the tolerance required. Guess keeping the tubes warm and dry is problematic.
The other incident involved a non-stabilized approach into Paris with another A340. This one had more help from the crew, with possible ATC assistance, in getting to the arrival gate not only high, but fast for a Cat III approach! The glideslope eluded them most of the way down. The aircraft at some point decided to go around, and a difference of opinion ensued between the crew and the ‘bus. It’s too long a story to relate here, but the crew and the automation never got on the same page, and let’s just say the outcome of the maneuver was seriously in doubt.
Before you think me anti-Airbus, recall that the Boeing Dreamliner, in pushing the performance envelope, has had a few miscues as well. Teething pains are one thing though, and ongoing incidents are something else—where one stops and the other begins is for your conjecture.
The principle concerning multifunctional devices states that the fewer functions any device is required to perform, the more perfectly it can perform those functions. Put more stuff on an aircraft, car, computer, home theater, or anything, and the reality is that it will break more frequently. DC-3s and Cessna 172s are prime examples of long-lasting simplicity.
Regarding automation for light aircraft, a certain amount is really good, and single-pilot flights in IMC without a simple and solid autopilot is much more work and distraction than it needs to be. However, remember Johnson’s First Law: When any mechanical contrivance fails, it will do so at the most inconvenient time.
My question is: How does it know?
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