Introduction:
After the success of three generations of the narrow-body aircraft B737, Boeing 737 MAX is designed and produced by Boeing Commercial Airplanes as the fourth generation of the Boeing 737, succeeding in the Boeing 737 Next Generation (NG).
This 737 series was publicly announced on August 30, 2011. The first 737 MAX airplane, named The Spirit of Renton, performed its first flight on January 29, 2016. The 737 MAX series gained FAA certification on March 8, 2017. The first delivery was a MAX 8 on May 6, 2017, to Malindo Air, which placed the aircraft into service on May 22, 2017. The 737 MAX is based on earlier 737 designs, re-engined with more efficient CFM International LEAP-1B engines, aerodynamic changes (including distinctive split-tip winglets), and airframe modifications.
According to Boeing website “The 737 MAX is the fastest-selling airplane in Boeing history with about 5,000 orders from more than 100 customers worldwide”
What's different about the Max?
Compared with previous 737 versions, the Max 8 has bigger, more powerful and more efficient CFM LEAP engines (more on those in a minute), improved aerodynamics and a redesigned cabin interior. It also can fly farther and carry more people than the previous generation of 737s, like the 737-800 and 737-900.
Lion Air Flight 610 crash
On October 29, 2018, Lion Air Flight 610, 737 MAX 8 registration PK-LQP, plunged into the Java Sea 13 minutes after takeoff from Soekarno–Hatta International Airport, Jakarta, Indonesia. The flight was a scheduled domestic flight to Depati Amir Airport, Pangkal Pinang, Indonesia. All 189 onboard died. This was the first fatal aviation accident and first hull loss of a 737 MAX. The aircraft had been delivered to Lion Air two months earlier. People familiar with the investigation reported that during a flight piloted by a different crew on the day before the crash, the same aircraft experienced a similar malfunction but an extra pilot sitting in the cockpit jumpseat correctly diagnosed the problem and told the crew how to disable the flight-control system. Following the Lion Air crash, Boeing issued operational manual guidance, advising airlines on how to address erroneous cockpit readings. The accident is under investigation with the final report expected to be released between August and September 2019.
Ethiopian Airlines Flight 302 crash
On March 10, 2019, Ethiopian Airlines Flight 302, 737 MAX 8 registration ET-AVJ, crashed approximately six minutes after takeoff from Addis Ababa, Ethiopia, on a scheduled flight to Nairobi, Kenya, killing all 149 passengers and 8 crew members on board. The aircraft was four months old at the time. The cause of the crash is unclear as of March 19, 2019, though the aircraft's vertical speed after takeoff was reported to be unstable. Evidence retrieved on the crash site suggests that, at the time of the crash, the aircraft was configured to dive, similar to Lion Air Flight 610. According to Ethiopian transport minister Dagmawit Moges, on April 4, the crew "performed all the procedures repeatedly provided by the manufacturer but was not able to control the aircraft". On May 21, CNBC reported that according to a person familiar with the matter, U.S. aviation officials believe a bird strike may have led to the crash of ET302. Boeing's shares rose in response to this information. The subsequent findings in the Ethiopian Airlines crash and the Lion Air crash led to the Boeing 737 MAX groundings across the world.
Accidents and incidents
In the two years of the 737 MAX's commercial service prior to its grounding, the global fleet of nearly 400 aircraft flew 500,000 flights and suffered two hull loss incidents. According to a statistical metric gathered on March 11, 2019, the 737 MAX's accident rate was second behind the Concorde, with four accidents per million flights, compared to the 737 Next Generation's 0.2 accidents per million flights.
On April 29, Boeing CEO Dennis Muilenburg stated that the aircraft involved were "properly designed" and that the crashes were caused in part by flight crew not fully following procedures that they were provided. On April 4, Muilenburg had said "It's our responsibility to eliminate this risk. We own it and we know how to do it.”
On May 14, reports surfaced of meetings between American Airlines pilots and Boeing executives before the Ethiopian Airlines crash, where the pilots asked Boeing to work urgently on a fix of the MCAS software. The FAA had already issued one directive after the Lion Air crash, instructing airlines to revise their flight manuals to include information on how to respond to a malfunction of the anti-stall system known as MCAS. In a closed-door meeting pilots and pilot union representatives argued that Boeing should push authorities to take an emergency measure that would likely had resulted in the grounding of the Max, including changes to the MCAS, while Boeing executives resisted. Mike Sinnet, Boeing Vice President present at the meeting, said he felt confident that pilots had adequate training to deal with a problem, especially now that pilots — who were not initially informed about existence of the new MCAS system — were aware of it. The pilots expressed frustration that Boeing did not inform them about the new software on the plane until after the Lion Air crash. "These guys didn’t even know the damn system was on the airplane, nor did anybody else," said Michael Michaelis, the union’s head of safety at the meeting. Mr. Sinnett said in the meeting. "The worst thing that can ever happen is a tragedy like this, and the even worse thing would be another one."
On May 18, 2019, Boeing admitted that flaws in 737 MAX simulator software made the system unable to reproduce flight conditions that contributed to the crashes in Ethiopia and Indonesia.
B737 Max Grounding
Ethiopian Airlines grounded its fleet on March 10. The Civil Aviation Administration of China ordered all MAX aircraft grounded in the country on March 11, stating its zero-tolerance policy and the similarities of the crashes. Most other regulators and airlines individually grounded their fleets in the next two days.
On March 11, the FAA issued a Continued Airworthiness Notification to the International Community (CANIC) for operators. The CANIC listed the activities the FAA had completed after the Lion Air accident in support of continued operations of the MAX.
On March 13, Canada received new information suggesting the similarity between the crashes in Ethiopia and Indonesia. Canadian Transport Minister Marc Garneau informed U.S. Transportation Secretary Elaine Chao of his decision to ground the aircraft. Hours later, President Trump announced U.S. groundings, following consultation among Chao, acting FAA administrator Daniel Elwell and Boeing CEO Dennis Muilenburg. The FAA issued an official grounding order, citing the new evidence and acknowledging the "possibility of a shared cause for the two incidents". The U.S., Canadian, and Chinese regulators oversee a combined fleet of 196 aircraft, nearly half of all 387 airplanes delivered.
What went wrong to cause these tragedies?
According to BBC News “Pilots of the crashed Ethiopian Airlines Boeing 737 Max were unable to prevent the plane repeatedly nosediving despite following procedures, an initial report has found.
The captain and first officer followed safety procedures recommended by Boeing. But they couldn't stop the aircraft going into a fatal dive shortly after takeoff from Addis Ababa on 10 March, the report by Ethiopian investigators said. All 157 people on board were killed.”
“The preliminary report into the accident, by Ethiopia's Aircraft Accident Investigation Bureau, said the plane's take-off appeared normal.
However, a short time later two sensors that measured the angle of the plane's flight began to record different reading”
What is the system under question?
The report did not attribute blame for the crash, but a detailed timeline suggests the pilots were struggling to deal with an automated safety system - known as the Maneuvering Characteristics Augmentation System (MCAS).
The system is designed to prevent the plane stalling when making steep turns under manual control.
How long is the 737 Max grounded for?
Still no clear answer about when the 737 Max will return to the skies, but it expected to be Dec 2019
References:
