Ethiopian Airlines Group CEO, Tewolde GebreMariam, visits the accident scene in Ethiopia hours after the March 10 crash. (Ethiopian Airlines Photo via Twitter) Readings from the recorders recovered from last month’s crash of an Ethiopian Airlines Boeing 737 MAX jet reportedly suggest that the pilots tried using the recommended procedure for overriding a balky automated flight control system — but that the system was re-engaged and forced the plane into its fatal dive. The reports by and , based on interviews with unnamed sources who have been briefed on the post-crash investigation’s preliminary findings, raise deeper questions about the safety of the flight control system, known as the Maneuvering Characteristics Augmentation System, or MCAS. Boeing added the MCAS system to the 737 MAX as a safeguard against stalling, but investigations into the Ethiopian crash on March 10 — and last October’s crash of a Lion Air 737 MAX in Indonesia — have focused on the possibility that spurious data from a single angle-of-attack sensor caused the system to force the planes into catastrophic nose dives. The Indonesia crash killed all 189 people on board, and the Ethiopian crash killed 157 people. In the wake of the crash in Ethiopia, all 737 MAX planes have been grounded worldwide. Boeing is working on a software update that it says should resolve the MCAS issue, but that fix is still thought to be weeks away. In the past, Boeing has stressed that pilots could remedy the scenario that led to the crashes by disconnecting the MCAS system and taking manual control of the jet’s stabilizer trim mechanism. But the latest reports quote sources as saying the Ethiopian Airlines pilots tried that procedure but didn’t fully execute it. Instead, the MCAS system was re-engaged, leading to the final, fatal plunge. The Journal’s sources speculated that pilots re-engaged the automated system because they couldn’t raise the nose using manual controls, while Reuters’ sources held out the possibility that the MCAS system could have re-engaged itself. a former Boeing flight control engineers, Peter Lemme, as saying that the pilots might have been stymied by excessive aerodynamic loads on the stabilizer trim control system. I *assume* the mistrim situation created excessive load opposing the manual jackscrew authority from the trim wheel. From what is reported, they must have tried to restore electric trim to get the stab to come up, but then MCAS swept in again. — Peter Lemme (@Satcom_Guru) This post includes a brilliant video showing the challenges with manual trim. The situation may be worse than portrayed, as stick shaker is going off, and the elevator feel shift will increase aft column “feel” forces as much as four times more than normal. — Peter Lemme (@Satcom_Guru) also laid out a scenario by which excessive loads could have foiled efforts to stabilize the jet. The Times noted chatter on an online aviation forum about an alternate procedure, outlined in a 1982 pilot training manual, that might have averted the manual lockup by repeatedly letting go of the control column and turning the cockpit’s stabilizer trim wheel manually. Boeing said it was premature to comment on the specifics of such reports. “We urge caution against speculating and drawing conclusions on the findings prior to the release of the flight data and the preliminary report,” the company said. The 737 MAX crashes are the subject of investigations in Ethiopia and Indonesia, with participation by Boeing, the Federal Aviation Administration, the National Transportation Safety Board and other entities. The FAA’s inspector general is conducting its own investigation into the process by which the 737 MAX was certified for flight, and the Justice Department has reportedly launched a grand jury investigation with participation by the FBI. Subpoenas have gone out to Lemme and other potential witnesses, .
Ethiopian Airlines employees conduct a memorial service on March 15 to pay tribute to colleagues and passengers who lost their lives in the March 10 crash of a Boeing 737 MAX 8 jet. (Ethiopian Airlines Photo) The latest word from the investigation of is that readings retrieved from the flight data recorder reportedly point to circumstances similar to those that surrounded a 737 MAX crash less than five months earlier in Indonesia. Regulators around the world suspected as much, based on data received via satellite from the plane during its minutes-long flight from Addis Ababa heading for Kenya on March 10. That’s what led them to last week. The March 10 crash killed all 157 people aboard Ethiopian Airlines Flight 302, while the October crash killed all 189 people aboard Lion Air Flight 610. In the Lion Air investigation, safety experts focused on an automatic flight control system known as the Maneuvering Characteristics Augmentation System, or MCAS. Boeing added the MCAS system to the 737 MAX to guard against having the airplane stall under extreme conditions. The measure was taken because the MAX’s engines are bigger than the engines on the previous line of 737s, changing the aerodynamics. Preliminary findings from the Indonesia probe suggested that the MCAS system was receiving spurious data about the plane’s aerodynamic “angle of attack” just after takeoff. That would lead the automatic system to force the plane’s nose downward into an uncalled-for dive. In the Lion Air case, the pilots repeatedly fought against the MCAS commands — and ultimately lost. Afterward, Boeing said pilots can use a procedure to disengage the MCAS system, but that procedure wasn’t followed by the Lion Air pilots. Today, Reuters quoted an unnamed source as saying the angle-of-attack readings from the Ethiopian Airlines jet’s flight data recorder were “very, very similar” to the Lion Air readings. The similarities will be the focus of further investigation, Reuters quoted its source as saying. The double disaster has raised deeper questions about the Federal Aviation Administration’s oversight of Boeing during the certification of the 737 MAX. Over the weekend, The Seattle Times quoted sources as saying that assessing the MCAS system’s safety. The Times said those analyses understated how much leeway the automatic system was given to move the horizontal tail in order to avoid a stall — or force a dive if the system malfunctioned. Another potential flaw with the system was that it depended on readings from a single angle-of-attack sensor, rather than multiple sensors. Much of The Seattle Times’ report was based on research conducted before the Ethiopian Airlines jet crashed. Aerospace reporter Dominic Gates wrote that “both Boeing and the FAA were informed of the specifics of this story and were asked for responses” a few days before the crash. People shouldn’t misread this point. I was not telling Boeing or the FAA anything they didn’t know.As noted, Boeing has been working since the first crash on a fix for the flaws my story listed — Dominic Gates (@dominicgates) In a , Boeing CEO Dennis Muilenburg said that “safety is at the core of who we are at Boeing” and that the company is working with authorities and airlines to support the investigation and “help prevent future tragedies.” “Soon we’ll release a software update for the 737 MAX that will address concerns discovered in the aftermath of the Lion Air Flight 610 accident,” Muilenburg said. That update, and revisions in pilot training procedures, should address the MCAS’ behavior in response to erroneous sensor inputs, Boeing says. that Justice Department and Transportation Department officials are reviewing how the 737 MAX was developed, and how the plane won its regulatory approvals. it gave to 737 MAX jets. U.S. Sen. Roger Wicker, R-Miss., has said he intends to hold a hearing into the issues raised by the crashes, in his capacity as the chairman of the Senate Commerce, Science and Transportation Committee. The committee’s ranking Democratic member is Sen. Maria Cantwell, D-Wash. She touched on the matter briefly in response to a question today at the . “Paramount in all of this is safety,” Cantwell told GeekWire. “So we’re going to keep looking at all the data and information until we are sure that we understand every aspect of this.”
Ethiopian Airlines CEO Tewolde GebreMariam visits the accident scene. (Ethiopian Airlines Photo via Twitter) Ethiopian Airlines said one of its Boeing 737 MAX 8 jets crashed today, just minutes after takeoff from Addis Ababa’s airport en route to Nairobi, Kenya, killing all 157 people aboard. It was the second fatal crash involving a recently delivered 737 MAX 8, following the last Oct. 29. Although it’s too early to speculate about the cause, the fact that two recently delivered 737 MAX 8 jets have been involved in catastrophic accidents — during the same phase of flight — is drawing attention from analysts. that today’s crash “is raising more intense questions — and speculation than usual after a crash because it comes in the wake of the Lion Air 737-8 crash last year.” “But be cautious about drawing conclusions at this stage,” Leeham’s Scott Hamilton wrote. “Until the black boxes are recovered, information is limited.” At a news conference in Ethiopia, Tewolde GebreMariam, the group CEO of Ethiopian Airlines, also counseled caution. He said Boeing and Ethiopia’s Accident Investigation Bureau would take part in the crash investigation. The U.S. National Transportation Board said it was , and Kenyan investigators were on their way as well. In a statement, Boeing said it was extended its sympathy and confirmed that it would send a technical team to assist in the investigation. Ethiopian Airlines said Flight 302 was , representing 35 nationalities. Eight Americans were said to be aboard. the flight had arrived in Addis Ababa, Ethiopia’s capital, earlier in the day from Johannesburg, South Africa, and headed out for Nairobi at 8:38 a.m. local time, flown by a senior captain with more than 8,000 cumulative flight hours. GebreMariam said the pilot reported difficulties just after takeoff from Bole International Airport. The pilot reportedly sought, and was given, permission to return to the airport — but contact was lost at 8:44 a.m., six minutes into the flight. The plane smashed into the ground violently in an area about 20 miles to the southeast, near the town of Bishoftu. A showed GebreMariam at the crash scene, surrounded by wreckage and disturbed earth. At first blush, the circumstances seem similar to those of the Lion Air crash in Indonesia. In that case, pilots reported difficulties maintaining level flight on their 737 MAX 8. Just minutes after takeoff, the plane pitched into a catastrophic dive. The suggest that an automatic flight control system known as the Maneuvering Characteristics Augmentation System, or MCAS, may have played a role in that incident. The MCAS system is a safeguard that’s meant to keep the 737 MAX from stalling under extreme aerodynamic conditions, but investigators surmised that the system was getting spurious data from sensors that measure air flow over the wings. Boeing says pilots have a procedure that can quickly resolve such an issue, but that procedure was not followed by the Lion Air pilots. The Lion Air accident focused heightened attention on the MCAS system, raising pilots’ awareness about the control issue and how to resolve it. Records show that the plane involved in today’s crash had its first flight . It was among, out of a that were ordered in 2014. The airline said the plane “underwent a rigorous first check maintenance” in February. In his , Hamilton said investigators are likely to consider a wide range of factors, including the MCAS issue as well as mechanical failure, human error and weather conditions. “It should be noted that Ethiopian is considered one of the best airlines in the world and the best in Africa,” he wrote. “It’s got a good safety record and service is considered very good. This is in contrast to the spotty safety record of Lion Air.”