China Plane Crash: What Happened? 26,000 ft. Drop in 95 Seconds Puzzles Experts

Mar. 22—A little over 24 hours after a China Eastern Airline plane crashed in the country's Guangxi province, igniting a large forest fire and killing all 132 on board, experts are working to understand why and how flight MU5735 fell 29,100 feet in the space of a few minutes. The steep dive has baffled experts, particularly since the plane seemed to be operating normally minutes before the tragic accident.

Emergency officials and those from the airline and the Civil Aviation Administration of China, are scouring the crash site but the force of the impact and the fire means debris has either scattered or burned.

Flight MU5735 was travelling from Kunming to Guangzhou when it plunged from cruising altitude.

> At 11.50 am (India time) the plane was cruising at 29,100 feet.

> 135 seconds later it nosedived to 9,075 feet.

> 20 seconds later it was just 3,225 feet above the ground.

The plane plunged almost 26,000 feet in 95 seconds.

And, in a twist, the dive seemed to halt for 10 seconds before resuming.

Experts puzzled by the plane's behaviour before crash

"It's very odd," Jeff Guzzetti, a former accident investigation chief for the United States' Federal Aviation Administration, the country's aviation regulatory body, told Bloomberg.

US-based aviation analyst Robert Mann told Reuters investigators would need the black boxes, or data recorders, to understand what happened.

The black boxes have not yet been recovered; Chinese media has said the government will give an update later Tuesday.

However, aviation experts seem to be at a loss to explain the events.

"It's an odd profile," John Cox, an aviation safety consultant and former Boeing 737 pilot, said, "It's hard to get the airplane to do this."

The plane was a 737-800, seen as one of the safest aircrafts ever made.

Focus of the investigation

The probe will try to determine why the plane made such an abrupt and severe dive, which sets it apart from earlier accidents.

Among other points, aviation experts will consider weather conditions and examine wreckage for any signs of possible malfunction.

Once the data recorders — which log conversations between pilots — are found, they will also see if distress calls were made.

"Accidents that start at cruise altitude are usually caused by weather, deliberate sabotage, or pilot error," Dan Elwell, former head of the US' FAA, told Reuters.

Early conclusions?

It is too early to draw conclusions, Benjamin Berman, a former investigator for Indonesia's National Transportation Safety Committee, told Bloomberg.

"It is possible to come up with many scenarios for malfunction, pilot miscues or some combination that led to the plunge," Berman said, "but none seem likely (in this instance)."

He echoed what Cox and Guzzetti said — the 737-800, like other jetliners, is designed so that it won't normally dive at steep angles.

This means it would likely take an extreme effort by a pilot or a highly unusual malfunction.

Many things can cause at least the start of a dive — an error, or the pilot suffering a heart attack and slumping onto the control column, or a mechanical failure.

But these tend to be short-lived — either because another member of the flight crew can take corrective action or the plane itself can counteract mechanical or system failures.

Looking forward for the Boeing 737-800

China, after the accident, said it would order the grounding of all 737s in China Eastern Airline's fleet till the investigation had concluded. In India, the Director-General of Civil Aviation put Indian carriers' 737 on 'enhanced surveillance'.

"Flight safety is serious business and we are closely studying the situation. In the interim, we are focusing on enhanced surveillance of our 737 fleets," DGCA chief Arun Kumar told PTI.

SpiceJet, Vistara and Air India Express have Boeing 737 aircraft in their fleet.

With input from Bloomberg, Reuters, PTI

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