Boeing Co. conceded Thursday that its anti-stall software bears some of the blame in the deadly crashes of two new 737 MAX airliners and promised that a patch engineers have spent months developing will prevent any recurrences.
“The history of our industry shows most accidents are caused by a chain of events; this again is the case here, and we know we can break one of the chain links in these two accidents,” CEO Dennis Muilenburg said in a statement after Ethiopian authorities issued an update on their investigation into the March 10 crash outside the capital of Addis Ababa that killed all 157 people. “It’s our responsibility to eliminate this risk. We own it and we know how to do it.”
The Chicago-based planemaker decided earlier this week to stretch out the timeline for delivering the software fix, promising to take as much time as necessary to get it right. The Federal Aviation Administration now says it expects to receive the final draft of Chicago-based Boeing’s software fix “over the coming weeks.”
The U.S. agency joined its international peers in grounding the aircraft after flight data from the downed Ethiopian Airlines plane showed choppy ascents and descents during takeoff, mirroring those before a Lion Air crash in Indonesia on Oct. 29.
The delay on a system the agency originally expected to approve by April follows a Senate hearing into the original certification of the aircraft, where lawmakers questioned the FAA’s relationship with the planemaker. The accidents have snarled airline schedules for the foreseeable future and prompted Transportation Secretary Elaine Chao to seek a review of the jetliner’s initial approval for commercial flights.
In the Indonesian crash, a malfunctioning sensor on a 737-8 MAX fed incorrect data on the airliner’s ascent vector to a computer system that attempted to lower the angle to avoid a stall, officials said. That prompted a struggle between computer software known as the Maneuvering Characteristics Augmentation System, or MCAS, and the pilot, who ultimately lost control of the aircraft.
All 189 people aboard were killed. The fact that Boeing hadn’t yet completed a software patch that the FAA mandated afterward was part of what prompted the high level of concern when the Ethiopian Airlines crash occurred.
The government’s investigation into the second accident shows the pilots followed the emergency procedures recommended by Boeing and approved by the FAA, Ethiopian Airlines said in a statement. “They could not recover the airplane from the persistence of nose diving,” the carrier said.
Boeing’s software update, “along with the associated training and additional educational materials that pilots want in the wake of these accidents, will eliminate the possibility of unintended MCAS activation and prevent an MCAS-related accident from ever happening again,” Muilenburg promised. “When the MAX returns to the skies with the software changes to the MCAS function, it will be among the safest airplanes ever to fly.”
The 737 MAX, the latest version of a plane flown since 1967, underwent less rigorous scrutiny beforehand than a totally new model would have, and the FAA relied heavily on inspections done by Boeing employees themselves under a system that delegates some duties to non-agency employees and organizations, including companies, that have particular expertise.
Seventy-nine organizations are authorized to handle such duties, acting administrator Randy Elwell told the panel, though the FAA retains the right to intervene directly at any time. Its personnel are always involved in level of safety determinations and establishment of rules for special situations, he added.
Evaluation of the MAX, from Boeing’s first permit application to final certification in March 2017, took five years and included 297 flight tests, some of which involved the anti-stall software linked to the first crash and under examination in the second, Elwell said.
Boeing has garnered more than 4,600 orders for the single-aisle jetliner, though just 67 of the aircraft are flown in the U.S. and fewer than 400 worldwide. The planemaker only began delivering the plane in 2017 and was working to ramp production up to 57 a month, which would have netted a potential $30 billion in sales this year, prior to the Ethiopian crash.
