Airplane Droppings

Pieces of airplane fall from the sky more often than you’d think.

MH370 Flap
Investigators carry the flap in question. It’s now in a French laboratory undergoing analysis.

Last week a local resident on Reunion Island discovered a large piece of machinery washed up on the beach. Authorities confirmed it’s part of a flap from a Boeing 777. Only one 777 currently is reported missing—Malaysia Airlines Flight 370, the passenger liner that mysteriously disappeared on March 8, 2014, somewhere over the Indian Ocean, with 239 people aboard. The airplane is thought to have crashed at sea, well off its charted course between Kuala Lumpur, Malaysia and Bejing, China, but an extensive (and ongoing) search failed to find even a trace of it. Ocean currents could easily have carried the flap from the crash site—wherever that is—to Reunion Island. But as of this morning, officials haven’t confirmed that the flap comes from MH370, partly because, as it turns out, pieces fall off airplanes more frequently than one would expect.

Aircraft are among the most complex machines a typical person regularly encounters, and modern airliners fly the kind of grueling schedules only machines can. Many airplanes average 16 hours a day in the air, for upwards of 20 years, before they retire. Their maintenance needs are complex and rigorous, but the people who design, build and maintain these machines are human. So it’s no surprise that once in a great while, a small mechanical stress point is overlooked in the design, or someone forgets to tighten the right screw, or a piece of metal becomes too brittle, and something falls off. It happens often enough to have its own acronym in the aviation safety community: TFOA, or Things Falling Off Aircraft.

A chunk of airliner plummeting from the sky is no trivial matter—a piece of landing gear assembly or metal paneling can weigh hundreds of pounds, and can easily crush anyone below. The good news is that such large parts are very carefully and securely attached.  “It’s rare that a piece of an aircraft that large would come off. That’s something that typically doesn’t happen,” says Anthony Brickhouse, a professor of applied aviation sciences at Embry-Riddle Aeronautical University. “It’s not totally unheard of for parts to come off aircraft, but as an accident investigator, the only times we see pieces that large coming off aircraft are accidents, where it suffered a structural failure or hit the water and broke apart.”

Even small pieces can prove fatal in particularly unlucky cases, such as the unnoticed engine cowl wear strip that a Continental Airlines DC-10 left behind on takeoff from a Paris runway in 2000, leading directly to a Concorde crash five minutes later. That was an anomaly, however, and generally those parts don’t harm anyone, though falling airplane pieces occasionally make the news for landing on someone’s house or car. Others likely hit the ground without notice and are never seen again, or are discovered only when the aircraft operator notices it’s missing.

“I wouldn’t eliminate design flaws, but typically when a part comes off a plane it’s a maintenance issue,” says Brickhouse. 

Commercial aircraft are visually checked after every flight, and any missing parts reported to the FAA. Each part carries serial codes, allowing them to be traced back to the manufacturer, and maintenance crews are legally required to catalogue even the most minor part replacements. If a missing piece is for some reason unreported by the aircraft operator and indistinguishable by serial code, the FAA can look over radar coverage to determine which aircraft were flying over the area. Takeoff and landing sequences generally entail the most complex mechanical motions and stresses, so many parts come down near an airport.

Also washing up on a quasi-regular basis are rocket parts—usually the payload shrouds used to protect satellites on their trip up through the atmosphere. Built hardily and jettisoned at relatively low altitudes, shrouds often survive the stresses to wash ashore. Ocean currents then return rocket parts from Arianespace’s launch facility in Kourou, French Guiana, and the U.S. pads at Cape Canaveral, to wash ashore on regional beaches.  

The Boeing 777 flap on Reunion Island would be an extraordinary discovery regardless of its origin, and is so rare, in fact, that MH370 is the assumed source. Embry-Riddle professor Brickhouse expects it will be confirmed as a piece of the Malaysian airliner following lab tests in France. In the meantime people are frantically searching Reunion beaches for other washed-up airplane debris—one piece made international headlines, but turned out to be from a stepladder. The tattered remains of a suitcase are more ambiguous, if not impossible to identify with certainty.

After all, there’s a lot of flotsam in the Indian Ocean. 

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