It will take months to pinpoint why an Ethiopian Airlines 737 Max 8 fell out of the sky in Addis Ababa on March 10, killing all 157 people on board. But the crash is already an urgent problem for Boeing, the jet’s manufacturer, and for nearly 50 airlines flying the plane.
The 737 Max is a new jet that has only been in fleets since 2017, and there have now been two fatal crashes, both of them shortly after takeoff. On Oct. 28, 2018, a LionAir 737 Max crashed off the coast of Indonesia, killing all 189 people on board. Investigators have not yet publicly identified the cause of that crash, though they reportedly suspect an automated system that could have put the plane in danger.
Two fatal crashes so early in the life of a commercial aircraft is highly unusual, and the fatal-accident rate of the 737 Max is now second-highest of the modern era, after the ill-fated Concorde. The 737 Max has only flown about 500,000 flights, estimates aviation-safety expert Todd Curtis of AirSafe.com. With two crashes causing fatalities, the fatal-accident rate of the 737 Max would be 4 flights per million. That’s far higher than for most modern airliners. The prior version of the 737, for instance, has flown 61 million flights and averages just 0.2 fatal flights per million.
“The number of flights for the Max is so small that one crash would make it an outlier,” says Curtis. “Two definitely makes it an outlier. You don’t need to be an epidemiologist to see the rate of accidents is much greater than for other 737s.”
Here are fatal-accident rates for most common jetliners of the last several decades:
Boeing has pitched the Max as a more efficient version of the workhorse 737, which debuted in 1967. For the Max, Boeing fitted bigger engines onto an airframe structurally similar to the prior generation’s, mounting them higher and further forward on the wing. That enabled a huge 14% improvement in fuel efficiency. But it also changed the plane’s center of gravity and its flying characteristics.
The new configuration can force the plane’s nose higher in certain situations, so Boeing designed a computerized system meant to compensate for that. When triggered, the system automatically pushes the plane’s nose down, to assure the plane doesn’t stall and lose lift. That system is now in focus, since pilots in both crashes appear to have struggled with a plane they couldn’t prevent from nose-diving.
Early speculation about the cause of plane crashes is often wrong, and many factors can contribute to a crash, including pilot error, training shortfalls, poor maintenance, sabotage and of course terrorism. Still, the similarity of the two 737 Max crashes has raised alarms and led several countries to ground use of the jets in their national fleets. In the United States, Southwest, United and American fly the 737 Max. They’ve all expressed confidence in the jet’s safety. The FAA issued a “continued airworthiness” notice for the airliner.
Last year, after the LionAir crash, Southwest added a supplemental sensor to the cockpits of its 737 Max jets, to guard against bad data that could activate the plane’s automatic stall-prevention system. That was in response to the possibility that bad data may have triggered the system in the LionAir crash, forcing the plane’s nose down when it shouldn’t have.
Boeing generally has a strong safety record and a good reputation among pilots. If a design flaw is responsible for the two 737 Max crashes, Boeing could engineer a fix that dramatically improves the Max’s safety record, over time. “Wait a few million flights, and maybe the comparison won’t be so outrageous,” says Curtis.
Rick Newman is the author of four books, including “Rebounders: How Winners Pivot from Setback to Success.” Follow him on Twitter: @rickjnewman