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Luz Lazo
Transportation reporter covering the Washington Metro, buses, Bikeshare Capital, taxis and the region's road network
Paul Schemm
Foreign Night Editor based in Addis Ababa, Ethiopia
April 4th
Federal aviation authorities ordered Boeing to settle a second problem with theft
The company admitted Thursday that new details revealed that pilots of two aircraft were unable to remedy a malfunction of the system by applying the procedures recommended by the company.
Ethiopian Airlines Flight 302 pilots performed all the procedures recommended by Boeing to save their 737 Max 8 aircraft but could not get it out of a flight.
System-induced dive, a preliminary report on the accident was completed Thursday.
In a brief summary of the long-awaited preliminary report on the 10 March accident, Ethiopian Transport Minister Dagmawit Moges told reporters that the "flight control system" had contributed to the plane's difficulty. to gain altitude after leaving the Addis Ababa airport. He crashed six minutes later, killing the 157 people on board.
She stated that the crew "had repeatedly performed all the procedures provided by the builder, but was not able to control the aircraft".
As after the crash of a Boeing 737 Max 8 in Indonesia in October, the focus of Ethiopian Airlines is focused on a flight control system known as the "flight control system". 39, increasing maneuvering characteristics, or MCAS, which lowers the nose of the aircraft. to avoid a stall.
But later on Thursday, Boeing confirmed to The Washington Post that he had discovered a second software-related problem that the Federal Aviation Administration had ordered to deal with, in addition to the anti-stall system being investigated under the two accidents and involved in the grounding of the system. l & # 39; air.
This additional problem concerns software affecting flaps and other flight control equipment and is therefore clbadified as critical for flight safety, said two officials familiar with the investigation.
The realization of a second software problem explains why the schedule that Boeing had publicly announced last week to again get hundreds of aircraft in flight was wrecked, officials said.
In the beginning, Boeing announced plans to submit corrections to the FAA for its anti-stall system for review last week. On Monday, an FAA spokesman said the agency was expecting instead to receive the final software "in the coming weeks".
One of the officials aware of the investigation said that everyone wanted a thorough review now because the worst result would be that another problem will appear later. "You do not want to be in a situation where there was a contributing factor in an accident, and then three weeks later you find another" problem that could affect a flight.
In a statement, Boeing described the additional problem as "relatively minor" but did not explain in detail how it affected the flight control system of the aircraft. "We are taking steps to thoroughly address this relatively minor problem and we already have the solution to address it," he said.
[[[[Read the preliminary crash report here]
Dagmawit did not mention MCAS specifically during the press conference on Thursday, despite repeated questions from reporters, but his comments suggested that the system was activated during the flight and that the pilots were not able to disable it following the procedures recommended by the company.
Boeing later admitted that the system had malfunctioned and apologized.
"At Boeing, we are sorry for the lives lost in the recent 737 MAX accidents," said General Manager Dennis A. Muilenburg. "These tragedies continue to weigh on our hearts and minds and we express our deepest condolences to the loved ones of pbadengers and crew members aboard Lion Air 610 and 302 flights of Ethiopian Airlines. We all feel the immense gravity of these events our society and recognize the devastation of families and friends of loved ones who perished.
"The government authorities will give all the details of what happened in the two accidents in the final reports, but with the release of the preliminary report of the accident investigation of the flight 302 of Ethiopian Airlines, it is Obviously, in both flights, the Augmentation System maneuvering features, known as MCAS, activated in response to erroneous information about the angle of the attack. "
The preliminary report, which does not determine the cause of the accident, recounts the last chaotic moments in the badpit before the accident.
[Ethiopian authorities describe similarities between jet crashes, but questions remain]
The report indicates that one minute after take-off from Bole International Airport, one of the angle of attack sensors sent erroneous information to the aircraft's computer system, thereby activating the shaker, a vibration in pilot commands that warns of imminent stall.
In response to the erroneous data, the MCAS intervened to force the aircraft to nose down. The MCAS activated at least four times and the pilots fought each time unsuccessfully to regain control of the aircraft.
Investigators believe that MCAS also contributed to the Lion Air flight crash on October 29th. The erroneous data provided by an attack angle sensor forced the system to force the nose of this aircraft several times. The pilots were unable to regain control and the aircraft Lion Air eventually plunged into the Java Sea, killing the 189 pbadengers on board.
After the crash in Indonesia, Boeing issued a bulletin explaining how to disable MCAS in case of malfunction, and Thursday's preliminary report indicated that Ethiopian pilots had followed this procedure.
According to the black box data published by Ethiopian investigators, pilots struggled to regain control of the aircraft through the system, which forced him repeatedly to descend. The pilots attempted to use a manual emergency trim system to try to lift the nose of the aircraft. The trim system is also used to stabilize an aircraft.
The captain called the "captain" three times to ask the first officer to lift his nose. During the final seconds of flight, the two pilots tried together to stop the dive of the plane but have not yet regained control of their flight, according to the report.
Experts say the plane was traveling too fast for the manual trim wheel to be used.
"At higher speeds, manual compensation may not be available due to [to] aerial load on the stabilizer, "said John Cox, a former pilot and aviation safety consultant, who was privately informed of evidence by people familiar with the investigation. "You can not manually generate enough force to move the pad."
During the final fight, described in the report, the aircraft tipped, finally plunged to 40 degrees and crashed to ground at 575 mph.
Amdeye Ayalew, who was responsible for investigating the accident, could have damaged one of the Ethiopian aircraft's sensors during take-off. According to information collected by the recovered data loggers, nothing indicates.
"We did not find any information about the damage caused by a foreign body to the plane," he said. "Is there a structural design problem? No, we can not verify this now. "
Officials said that a full report would be completed in the year following the accident.
[All eyes are watching as Boeing prepares software update months after Indonesia plane crash]
Ethiopian Airlines said the report absolved the pilots, who "followed the emergency procedures recommended by Boeing and approved by the FAA".
"Despite their hard work and strict adherence to emergency procedures, it was very unfortunate that they could not recover the plane from the persistence of the dive," said the airline .
The new jetliner revelations come after Boeing, struggling with the fallout from the two fatal accidents, described upgrades to the aircraft's software and reinforced the training of the 737 Max pilots.
After the crash of Lion Air, Boeing proposed in November a software patch that would have prevented MCAS from finding itself in a situation similar to that which had developed during the flight of Ethiopian Airlines, according to a document obtained by The Post.
[Ethiopian official: Black box data shows ‘clear similarities’ between Ethiopian Airlines, Lion Air crashes]
The FAA reviewed the proposal and negotiated the terms of the repair with Boeing in January, according to the document.
One of the last steps to certify that the patch was sufficient was a series of test flights by FAA pilots, which had been scheduled several weeks in advance for the second week of March.
It turned out to be the week of the crash of Ethiopian Airlines.
Internally at Boeing, a committee of engineers to revise the 737 Max quickly discovered the second software problem, according to the company. The flaw was shared with the FAA, which decided that it should also be handled via a software update.
Boeing said it would take about an hour for technicians to load the MCAS software update for the aircraft. The hotfixes will change the way that MCAS receives the information, requiring signals from both angle-of-attack sensors rather than just one before the release of the anti-stall system. It is unclear how the additional problem will affect the update schedule.
The updated MCAS will also have more limits on the frequency of engagement, and Boeing will make changes that will prevent the stall function from tilting the aircraft's nose too much in an attempt to correct a possible stall.
On Wednesday, Boeing announced that Muilenburg's CEO had joined the pilots on board a flight to test the updated MCAS software as part of the certification requirements and that it "was working as intended."
Boeing introduced MCAS, an unprecedented computerized device designed to fold the nose of the aircraft to combat the increased lift provided by the new engines and to prevent a "stall" likely to cause the crash of the aircraft.
There are 17 generations of 737s since the beginning of his flight and Boeing wanted the Max to behave just like its predecessor, the 737 NG.
The Max 8 Pbadenger Airliner is the most recent version of the 737 line – the most popular airliner in the world, which flew for the first time in 1967. The Max Airplane has was the most sold in the history of Boeing, with nearly 4,700 sold or ordered. .
The criminal division of the Department of Justice examines the Max jets, while the Inspector General of the Department of Transport investigates the manner in which they were certified. Transportation Secretary Elaine Chao has formed a "special committee of experts" to review aircraft certification procedures.
The FAA announced last Wednesday the creation of a technical review team led by a former senior US transport safety official, including representatives from NASA and foreign aviation authorities.
According to the preliminary report, the aircraft's data logger was found on March 11 and contained data for 73 hours of operation, covering 16 flights, including the fatal flight. The voice recorder, which was found on the same day, contained just over two hours of information, which included the previous flight in addition to flight 302.
The plane crashed into a farm field and the wreckage showed evidence of a "high energy impact". There was no indication of fire. The accident created a crater with a depth of about 33 feet, a width of 92 feet and a length of 131 feet. Most of the wreckage of the aircraft was buried in the ground, but small fragments were found scattered in an area about 656 feet wide and 984 feet long.
Schemm reported from Ethiopia. Ashley Halsey III and Lori Aratani in Washington contributed to this report.
Read more:
With links to Washington, Boeing has taken up more and more of the FAA's work
& # 39; My child! My brother! "While the mourners gather at the crash site of the Ethiopian Airlines company, an atrocious search for remains
The flight of Ethiopian Airlines to Nairobi crashes, the 157 pbadengers aboard being killed
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