The crash of an Ethiopian Airlines Boeing 737 MAX 8 near Addis Ababa March 10 has triggered voluntary groundings of in-service MAX-family aircraft even as investigators only begin their work, as concerns over possible links to last October 2018’s Lion Air MAX 8 crash mount, despite evidence of any clear links between the two crashes. 

Ethiopian flight ET302 went down at about 08:44 local time, six min. into a scheduled flight to Nairobi. Its crew radioed that it was having an issue and requested to return to Bole International Airport. It crashed shortly after, killing all 157 people onboard.

“From the air traffic control record, the pilot mentioned that he had difficulties and he wanted to return” to Addis Ababa, “so he was given clearance,” Ethiopian Airlines CEO Tewolde Gebremariam said hours after the accident. “While it was in flight at around 08:44 a.m., [the aircraft] had difficulties and it was lost from radar.” The aircraft descended at a high rate of speed, data from online flight-tracking sites show, and was destroyed on impact.

Investigators recovered both the flight data and cockpit voice recorders from the accident scene on March 11, the airline announced. Information from the devices should be able to shed some light on what little is known about the flight’s circumstances or the aircraft’s technical condition. The aircraft, ET-AVJ was delivered less than five months ago. Gebremariam said the aircraft had no recent maintenance write-ups in the days leading up to its final flight.

“From the records that we have, it was a clean airplane,” Gebremariam said. “The routine maintenance checks didn’t reveal any problems. I confirmed that it was a clean airplane.”

Flightradar24 data indicates the aircraft operated what appears to be a routine climb and acceleration for the first minute of its flight. The aircraft then leveled off at around 8,150 ft. before descending slightly. ET-AVJ reached a speed of close to 400 knots. Flightradar24 reports significant variation in vertical speed, although that data may be unreliable.

The aircraft arrived in Addis Ababa from Johannesburg at about 05:30 a.m. March 10 after completing a routine scheduled flight—its third five-hr. segment between the two cities within 24 hrs. Gebremariam said the aircraft’s records show no “technical remarks” following the last Johannesburg-Addis Ababa leg, and nothing was noted during its roughly three hrs. on the ground before its final departure.

On March 8, the aircraft was scheduled to operate flights 2861 and 2860 to Pointe Noire and back, but both services were canceled for an unknown reason. The aircraft remained on the ground in Addis Ababa.

The aircraft had its first “rigorous” maintenance check on Feb. 4, the airline said in a statement. “It was a brand-new airplane. Well-maintained,” Gebremariam said.

Flight ET302’s captain, Yared Getachew, had “more than” 8,000 flight hrs. and became a 737 captain in November 2017, the airline said. He joined Ethiopian in July 2010. “He has been flying with Ethiopian airlines with an excellent flying record,” Gebremariam said.

First officer Ahmed Nur Mohammed had 200 flight hrs., the airline said.

“An investigation will be carried out to determine the cause of the accident, in collaboration with all stakeholders including the aircraft manufacturer Boeing, Ethiopian Civil Aviation Authority and other international entities. A committee comprising Ethiopian Airlines, Ethiopian Civil Aviation Authority and Ethiopian Transport Authority has been set up to carry out the investigations,” the airline said.

Several operators including Ethiopian as well as Civil Aviation Administration of China (CAAC), not satisfied with waiting for answers, took the extraordinary precaution of grounding in-service MAXs until more is learned about the accident’s possible cause, and whether it is linked to the Lion Air accident.

FAA said late March 11 it would issue a global “continued airworthiness notification” concerning 737 MAX operations. The bulletin, which is advisory in nature and will not ground aircraft, is expected to reiterate messages sent following the Lion Air accident. FAA said it “has a team on-site” in Addis Ababa “collecting data and keeping in contact with civil aviation authorities.” The agency will “take immediate and appropriate action” if it identifies a safety-of-flight issue, it added.

Any action would likely come because of a definitive link between the Ethiopian and Lion Air accidents. Lion Air Flight 610 (JT610) crashed on Oct. 29, 2018 near Jakarta, Indonesia. The aircraft, registered PK-LQP, had been delivered to Lion Air two months before the crash. All 189 people on board were killed when the aircraft impacted with the sea around 13 minutes after takeoff. 

The Lion Air aircraft had a history of unreliable speed data input over the previous days, but was retained in scheduled service after it had been cleared for operations by the airline’s maintenance division. The investigation is ongoing. One of the aspects being looked at is the maneuvering characteristics augmentation system (MCAS), a new flight control law that operates only in flaps-up manual flight that Boeing introduced on the MAX family to help it handle more like its 737NG predecessor.

Information released by Indonesian investigators show JT610’s flight crew struggled to keep the MAX 8’s nose up, apparently working to counter MCAS, which was automatically pushing the nose down in response to the erroneous speed data. A procedure that would override MCAS was apparently not followed by the JT610 crew, although it is unclear how much they understood about the failure sequence. The aircraft dove into the Java Sea.

In the days after the Lion Air accident, Boeing issued messages to operators expanding on MCAS, and reiterating that the procedure for overriding erroneous automatic, repeated, nose-down inputs remained unchanged from previous 737 models. The FAA issued an emergency airworthiness directive requiring MAX operators to update their flight manuals with Boeing’s MCAS information. Boeing's messages and the mandate did not call for any new training or changes to the system itself.

Boeing has booked more than 5,100 orders for 737 MAX-family aircraft and delivered about 370. The first 737 MAX 8 entered service in May 2017.

Boeing has declined comment beyond expressing condolences for the victims and pledging to support the probe.

Sean Broderick, sean.broderick@aviationweek.com

 Jens Flottau, jens.flottau@aviationweek.com