Wednesday, June 3, 2009

In Aviation, There Isn’t Always a Plan B

While they investigate and speculate what brought down Air France Airbus, flight 447 over the Atlantic Ocean, the leading candidate remains violent weather.

You’ve no doubt read about thunder cells towering to 60,000 feet in the vicinity of the accident.  Some media have argued these storms can bring down an airliner. Aviation experts say it is unlikely. In truth the incredible strength and redundant systems of the modern day airliner assure that all but the absolutely most violent weather cannot harm it.

Some odd things can. Canadian Geese, as readers of Sully’s Saga ending in the Hudson River have seen.  These are huge animals which, when sucked into vital parts of an airplane, can bring it to ground. (The geese didn’t fare so well either.)

Which brings us to Flight 447 and an incident that happened to an airliner shortly before the Air France catastrophe. An SAS Norway 737 airliner suffered a mid-air collision with a living entity and was forced to make an emergency landing to prevent possible disaster.

When you read below what the entity was, you may laugh. But the same website that reported the SAS incident--Aviation Herald--recounted one historical precedent. A related incident caused the crash of a 757 airliner en route from the Dominican Republic to Frankfurt, Germany, with the death of all 189 passengers and crew on board.

What brought down the Frankfurt-borne jet, and caused the emergency landing of the SAS airliner?

Insects. That's right, insects.

A number of insects brought down the 757, a single Bumblebee caused the 737’s emergency landing.

You may now pause to speculate how this happene, and no, the insects weren’t inside the aircraft distracting the pilots.

Are you ready?  

In the 737 incident May 30, the Bumblebee was ingested in one of the aircraft’s pitot tubes. A pitot tube is a small, straw-like device that gives the aircraft’s speed. When the two pitot tubes disagreed on actual airspeed, the Captain chose to declare an emergency and land, which he did safely.

In the other incident, the aircraft had been on the ground for 25 days, and one or more insects got into the pitot tubes. One device apparently indicated the plane was flying too slow and about to stall, the other that it was unsafely over speeding. The crew could not resolve the issue and it crashed. For details, see Aviation Herald





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