Fatal flights: What we know about Boeing MAX 8 crashes in Ethiopia and Indonesia

The two plane crashes - one in Indonesia, the other in Ethiopia - that led to the worldwide grounding of Boeing 737 MAX 8 planes displayed similarities that linked them right away. On Thursday, Boeing CEO Dennis Muilenburg assumed responsibility for the flight-control problems that contributed to the accidents, saying, “We own it.’’

Here’s a look at the commonality and differences between the crashes:

Likely cause

At the time Lion Air Flight 610 plummeted into the Java Sea off Indonesia on Oct. 29, killing all 189 aboard, hardly anybody had heard of MCAS, the aircraft’s new anti-stall system. That included the pilots, whom Boeing had failed to notify with the reasoning that the revamped model flew much like the old 737.

Some of the evidence about that tragedy and the crash of Ethiopian Airlines Flight 302 on March 10 pointed to erroneous readings from a single angle of attack sensor that activated MCAS – and repeatedly pitched the planes’ nose down – as major factors, and Muilenburg acknowledged as much.

While aviation experts often point out crashes are not caused by a single reason, the problems with MCAS and the pilots’ lack of familiarity with the system certainly stand out.

“As pilots have told us, erroneous activation of the MCAS function can add to what is already a high workload environment,’’ Muilenburg said. “It’s our responsibility to eliminate this risk.’’

Flight pattern

The link between the two catastrophes was not established merely because both involved the same airplane model. The Federal Aviation Administration, which was days behind its counterparts elsewhere in calling for the MAX jets to be grounded, based its decision on satellite tracking that showed the flights followed a similar path.

In both cases, the pilots struggled to control the aircraft shortly after takeoff, as the jets experienced drastic changes in airspeed and altitude before lurching down. The Ethiopian Airlines flight was in the air for six minutes; the Lion Air flight for 12.

Weather was not considered a factor in either crash.

Desperate last moments

Data from the cockpit voice recorder has shed light on how the pilots reacted in both situations, and it appears they were overwhelmed by the MCAS malfunction.

MCAS was a foreign concept when the Lion Air flight took off from Jakarta, and according to media reports, as the tension mounted and control of the plane remained elusive, Indian-born pilot Bhavye Suneja flipped through a technical manual trying to find a solution.

His Indonesian first officer, known by the single name Harvino, prayed for a miracle.

The Ethiopian flight lasted half as long and ran into trouble almost from the first minute, with the aircraft barely 500 feet in the air. The Wall Street Journal reported an exchange between captain Yared Getachew and co-pilot Ahmed Nur Mohammed as one tells the other, “Pitch up! Pitch up!’’

Shortly afterward, the radio went dead and the planed plummeted onto a field outside the Ethiopian capital of Addis Ababa, killing all 157 aboard.

Maintenance

Ethiopian is known as one of the top airlines in Africa, with a strong safety record and a fleet featuring mostly newer aircraft. No maintenance issues had been reported on its MAX 8 plane and there was no reason to fear any mishaps when Flight 302 took off for a two-hour trip to Nairobi, Kenya.

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Indonesia’s Lion Air does not enjoy the same sterling reputation, given its history of safety lapses. Data-reading problems were reported in the four flights before the disaster, including one the previous day when the plane jerked so violently that some passengers vomited.

That’s believed to be the same flight in which an off-duty pilot traveling on the jump seat recognized the malfunction, overrode the automated system and controlled the plane.

Pilot experience and training

Some U.S. pilots who have flown the 737 series – but not the MAX – have wondered aloud why the aviators on both flights didn’t manually stop the trim wheel, a piece of equipment in the cockpit console that controls the horizontal stabilizer on the plane’s tail.

Pilots for airlines elsewhere in the world train under a different system that requires fewer flight hours than their American counterparts, and Nur had only 200 hours of experience, an unthinkably low total for a first officer on a 737 for a U.S. airline.

But Getachew was highly experienced with more than 8,000 hours, and both Suneja and Harvino had more than 5,000 hours.

A bigger factor might have been training on a MAX simulator, which Ethiopian officials said both Getachew and Nur had. It’s not known whether Suneja and Harvino did, but it appears unlikely considering the simulators’ scarcity.

At a news conference in Addis Ababa, Ethiopian Minister of Transport Dagmawit Moges said Getachew and Nur did everything by the book as they attempted to keep the plane from nosediving.

“The crew performed all the procedures repeatedly provided by the manufacturer but were not able to control the aircraft,’’ Moges said.