How hard did Malaysia Airlines Flight 370 hit the water after it ran out of fuel and plummeted from cruising altitude? Not as hard as you might think, accident experts say.
The relatively intact condition of the wing piece that washed up on Reunion island off Africa suggests the Boeing 777 may have hit the water more gently than in a head-on crash, according to former U.S. National Transportation Safety Board investigators Greg Feith and Jim Wildey, and Hans Weber, president of aviation consultant Tecop International Inc.
“That piece maintained its integrity. It’s not crushed,” Feith, a former senior investigator with the NTSB, said by phone from Denver. “You can deduce it was either a low-energy crash or a low-energy intentional ditching.”
Malaysian Prime Minister Najib Razak’s statement early Thursday that the piece, known as a flaperon, came from Flight 370 confirms that the plane crashed in the Indian Ocean. But it brings investigators and family members of the deceased no closer to understanding why the plane deviated from its Kuala Lumpur-to-Beijing route and what happened in the flight’s final moments.
There’s no firm evidence of the angle at which the plane hit the sea, let alone whether a pilot was at the controls. A high-powered stalling crash, like the one that plunged Air France Flight 447 into the Atlantic Ocean in 2009, isn’t the only way a plane can fall into the sea.
“The speculation among pilots right now is that it must have come down at a relatively shallow angle,” said Tracy Lamb, an aviation safety consultant and former Boeing 737 pilot. “It looks like the flaperon was broken off by the engine pod ripping off as it was dragged through the water on the initial impact.”
Despite their lumbering appearance, commercial aircraft are quite capable of gliding considerable distances without engine power. After birds were sucked into its engines over The Bronx in 2009, U.S. Airways flight 1549 completed a turn and flew about two-thirds of the length of Manhattan island before ditching in the Hudson River.
In a 2001 incident, an Airbus Group A330 en route from Toronto to Lisbon ran out of fuel over the Atlantic and glided for 144 kilometers (90 miles) before landing 19 minutes later at a coastal airfield in the Azores islands.
That might explain why the seafloor search for MH370 found no evidence of the aircraft in the immediate vicinity of a zone where its fuel is thought to have run out.
The Australian Transport Safety Bureau initially searched in a box 10 nautical miles on either side of that zone on the assumption that the plane would have plummeted in a fairly tight spiral into the sea, Commissioner Martin Dolan said in an interview in March.
The zone has since been extended to a wider radius to cover the possibility of a lower-energy crash at a more shallow angle.
Such a scenario would help explain the absence of debris on the ocean surface, Tecop’s Weber said.
“A nose-first plunge is unlikely, in my opinion, since the part is too big and intact for that,” he said by phone. A higher-energy impact would tend to disintegrate large objects like the flaperon found on Reunion: “Such a plunge should have resulted in the plane being shattered into smaller pieces.”
The absence of debris from the crash has confounded investigators. Previous crashes in water have almost always left floating debris, the bureau said in a briefing note on its website yesterday.
Much of that debris could have sunk by the time the surface search began in that area nine days after the plane disappeared.
“By this time much of any debris left floating after the crash would likely have either sunk or have been dispersed,” the bureau wrote. “The opportunity to locate and recover debris from the sea surface diminishes rapidly over the first few weeks from the time of a crash.”
Investigators scanned 4.6 million square kilometers (1.8 million square miles) of ocean surface, with 29 aircraft carrying out 334 flights and 14 ships on the sea as part of the operation, Australian Deputy Prime Minister Warren Truss said at a press conference in May.
There are other possibilities to explain the good condition of the flaperon. Other parts of the plane could have taken the brunt of the crash, shielding the wing, according to Jim Wildey, former chief of the NTSB’s materials laboratory.
While pictures of the flaperon suggest the crash was relatively benign, “if they find just one piece, it’s going to be a far stretch” to assess how the accident occurred, he said in an interview.
That hasn’t stopped conjecture among pilots puzzled by the chain of events.
“It’s currently speculated by a lot of other pilots in the industry that there was a pilot at the controls,” consultant Lamb said. Someone might have needed to adjust the degree at which the nose was pointing up or down to get the plane from cruising flight to a shallow-angled descent.
Any resolution to the mystery will depend on more detailed analysis of the flaperon, and ultimately on discovery of the flight recorders somewhere on the Indian Ocean floor.
“Was the flaperon extended, which would indicate that it was flown under pilot control?” Weber said. “Sounds crazy, but there is no scenario for this accident that doesn’t have some crazy aspect to it.”