2 Years After Being Grounded The Boeing 737 Max Is Flying Again
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The Boeing 737 Max 8.
Boeing
Two years after it was banned from flying passengers, the 737 Max has been cleared to return to the skies in much of the world. As part of their decisions, aviation safety agencies in the US, Brazil, Côn Đảo Canada, Australia, the UK, the European Union and elsewhere have ordered Boeing and airlines to make repairs to a flight control system ; update operating manuals; and increase pilot training. China, the , is still prohibiting the plane from flying, however, and it hasn't indicated when it'll reverse course.
The beleaguered aircraft was grounded worldwide on March 13, 2019, after two crashes, one in Indonesia in 2018 and the other in Ethiopia in 2019, . Apart from the human tragedy, it was a huge blow to Boeing's business, since the company has thousands of 737 Max orders on its books. In addition to the flight control system at the center of both investigations, other reports identified concerns with the airliner's , .
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Airlines are now slowly adding the 737 Max back into their schedules. Southwest was the latest carrier to do so when it resumed flights March 11. The plane is now back in service with all US carriers, but Boeing will have to work vigorously to retain the trust of airlines and the flying public in regard to the Max family. Here's everything else we know about what's happened with the airliner.
What happened in the two crashes?
In the first crash, on Oct. 29, 2018, dove into the Java Sea 13 minutes after takeoff from Jakarta, Indonesia, killing 189 people. The flight crew made a distress call shortly before losing control. That aircraft was almost brand-new, having arrived at Lion Air three months earlier.
The second crash occurred on March 10, 2019 when Ethiopian Airlines flight 302 departed Addis Ababa Bole International Airport bound for Nairobi, Kenya. Just after takeoff, kinh nghiệm du lịch côn đảo the pilot radioed a distress call and was given immediate clearance to return and land. But before the crew could make it back, 40 miles from the airport, six minutes after it left the runway. Aboard were 149 passengers and eight crew members. The aircraft involved was only four months old.
The 737 Max 9, shown here at the 2016 Paris Air Show, is a larger version of the Max 8, but with the same piloting system that's under investigation.
Kent German/CNET
What caused the crashes?
Planes crashes rarely have a single cause, which is the case here. On Oct. 25, 2019, the Indonesian National Transportation Safety Committee on the Lion Air crash. The report identifies nine factors that contributed to the crash, but largely blames MCAS. Before crashing, the Lion Air pilots were unable to determine their true airspeed and altitude and Côn Đảo they struggled to take control of the plane as for about 10 minutes. Each time they pulled up from a dive, MCAS pushed the nose down again.
"The MCAS function was not a fail-safe design and did not include redundancy," the report said. Investigators also found that MCAS relied on only one sensor, which had a fault, and flight crews hadn't been adequately trained to use the system. Improper maintenance procedures, confusion in the cockpit and the lack of a cockpit warning light (see next question) contributed to the crash, as well.
More on the Lion Air accident report
On March 9, 2020, almost one year to the day since the crash in Addis Ababa, Ethiopia's Aircraft Accident Investigation Bureau . Like the Indonesian findings, it cites design flaws with MCAS such its reliance on a single . It also blamed Boeing for providing inadequate training to crew on using the Max's unique systems. (The Seattle Times on the report.)
Unlike their Indonesian counterparts, the Ethiopian investigators do not mention maintenance problems with the plane nor does it blame the flight crew. "The aircraft has a valid certificate of airworthiness and maintained in accordance with applicable regulations and procedures," the report said. "There were no known technical problems before departure."
Remember that crash investigations are tremendously complex -- it takes months to evaluate the evidence and determine a probable cause. Investigators must examine the debris, study the and, if possible, check the victims' bodies to determine the cause of death. They also involve multiple parties including the airline, the airplane and engine m by the time of the first crash.) 162 and 210 passengers, depending on the configuration, it's designed for short- and medium-haul routes, but also has the range (3,550 nautical miles, or about 4,085 miles) to fly and between the . The larger first flew in 2017, and the Max 10 has yet to fly (, 2019). The smaller 737 Max 7 in May 2018.
The design of the 737 Max series is based on the Boeing 737, an aircraft series that . As a whole, the 737 family is the best-selling airliner in history. At any given time, thousands of some version of it are airborne around the world and some airlines, like Southwest and Ryanair, have all-737 fleets. If you've flown even occasionally, you've most likely flown on a 737.
What's different about the 737 Max series compared with earlier 737s?
The 737 Max can fly farther and carry more people than the , like the 737-800 and 737-900. It also has improved aerodynamics and a and flies on bigger, more powerful and more efficient CFM LEAP engines. CFM is between and France's Safran.
A 737 history
Those engines, though, required Boeing to make critical design changes. Because they're bigger, and because the 737 sits so low to the ground (a deliberate design choice to let it serve small airports with limited ground equipment), Boeing moved the engines slightly forward and raised them higher under the wing. (If you place an engine too close to the ground, it can suck in debris while the plane is taxiing.) That change allowed Boeing to accommodate the engines without completely redesigning the 737 fuselage -- a fuselage that hasn't changed much in 50 years.
But the new position of the engines changed how the aircraft handled in the air, creating the potential for the nose to pitch up during flight. A pitched nose is a problem in flight -- raise it too high and an aircraft can stall. To keep the nose in trim, Boeing designed software called the Maneuvering Characteristics Augmentation System, or MCAS. When a sensor on the fuselage detects that the nose is too high, MCAS automatically pushes the nose down. (For background on MCAS, read these excellent in-depth stories from and .)
Compared with previous versions of the 737, the Max's engines sit farther forward and higher up on the underwing pylons.
Andrew Hoyle/CNET
When was the Max grounded?
About 30 airlines operated the Max by the time of the second crash (the three largest customers being Southwest Airlines, and Air Canada). Most of them their planes a few days later. Besides the airlines already mentioned that list includes United Airlines, WestJet, Aeromexico, Aerolíneas Argentinas, GOL Linhas Aéreas, Turkish Airlines, FlyDubai, Air China, Copa Airlines, Norwegian, Hainan Airlines, Fiji Airways and Royal Air Maroc.
More than 40 countries also banned the 737 Max from flying in their airspace. China (a huge Boeing customer and ) led the way and was joined by Indonesia, Thailand, Malaysia, Australia, India, Oman, the European Union and Singapore. Canada initially hesitated, but soon .
Up until March 13, 2019, the FAA also declined to issue a grounding order, saying in a statement that there was "no basis to order grounding the aircraft." That was despite a public outcry from and . But following President Trump's the Max that day, the agency cited it had collected and analyzed.
Older , like the 737-700, 737-800 and 737-900, don't use MCAS and weren't affected.
Of the four 737 Max versions, only the Max 10 has yet to fly.
Boeing
What was the problem with the warning light?
reported March 12, 2019 that the Lion Air plane lacked a warning light designed to alert pilots to the faulty sensor and that Boeing sold the light as part of an optional package of equipment. When asked about the warning light, a Boeing spokesman gave CNET the following statement:
"All Boeing airplanes are certified and delivered to the highest levels of safety consistent with industry standards. Airplanes are delivered with a baseline configuration, which includes a standard set of flight deck displays and alerts, crew procedures and training materials that meet industry safety norms and most customer requirements. Customers may choose additional options, such as alerts and indications, to customize their airplanes to support their individual operations or requirements."
But on April 29, 2019, said that even for airlines that had ordered it, the warning light wasn't operating on some Max planes that had been delivered (a fact the Indonesian accident report confirmed). Then on June 7, 2019, Reps. Peter DeFazio, a Democrat from Oregon, and Rick Larsen, a Democrat from Washington, said suggesting that even though the plane maker knew the safety alert wasn't working, it decided to wait until 2020 to implement a fix.
Boeing responded to DeFazio and Larsen in a statement sent to CNET the same day.
"The absence of the AOA Disagree alert did not adversely impact airplane safety or operation," the statement read. "Based on the safety review, the update was scheduled for the MAX 10 rollout in 2020. We fell short in the implementation of the AoA Disagree alert and are taking steps to address these issues so they do not occur again."
The original version of the 737 first flew in 1967.
Boeing
What kind of MCAS training did 737 Max pilots receive?
Not much, which was a factor cited in both crash reports. As the Indonesian report said, "The absence of guidance on MCAS or more detailed use of trim in the flight manuals and in flight crew training, made it more difficult for flight crews to properly respond." Airline pilots are thoroughly trained to fly an aircraft under extraordinary circumstances, but they need accurate information about factors like airspeed and altitude to be able in an emergency.
Though MCAS was a new feature, existing 737 pilots didn't have to train on a simulator before they could start flying the Max. Instead, they learned about the differences it brought through . MCAS received scant mention. The reason? It was because Boeing, , wanted to of certifying pilots who'd already been trained on other 737 versions. To do so, Boeing and the FAA treated the Max as just another 737 version, rather than a completely new airplane (which it pretty much is).
Pilot emerged quickly after the Lion Air crash. On Nov. 12, 2018, that Max pilots from Southwest Airlines were "kept in the dark" about MCAS. similar complaints from American Airlines pilots four months later.
The previous model, the 737-900ER, doesn't have the MCAS flight control system.
Boeing/Ed Turner
What other issues with the aircraft besides MCAS were identified?
There are a few.
In December, 2019, the FAA said with two bundles of wiring that power control surfaces on the aircraft's horizontal stabilizer. Because the bundles are close together, there's a remote possibility that they could short-circuit and (if not noticed by the flight crew) send the plane into a dive. Boeing initially argued , since earlier 737s have the same wiring design, and has proposed .The same month, the FAA said that verify whether key systems on the aircraft are functioning correctly.Then in February, 2020, Boeing for the stabilizer trim system, which raises and lowers the Max's nose. The indicator, which notifies pilots of a malfunction, was turning on when it wasn't supposed to. Boeing also investigated whether from lightning strikes in flight. Separately, CFM International said there with a rotor on the Max's engines.In April, 2020, the FAA instructed Boeing to the airplane beyond MCAS. One, a possible fault in a flight control computer, could lead to a loss of control from the horizontal stabilizer, while th advising 737 Max operators to deactivate MCAS if a flight crew encountered conditions like the Lion Air pilots experienced. It also for victims' families and in support, and the US grounding order.
"There is no greater priority for our company and our industry," Boeing said in a March 13, 2019 statement. "We are doing everything we can to understand the cause of the accidents in partnership with the investigators, deploy safety enhancements and help ensure this does not happen again."
As is common after a crash, on preliminary findings of either investigation, but the day after the Ethiopian crash the company issue a software update that would include changes to MCAS, pilot displays, operation manuals and crew training.
Following the Lion Air accident report, then CEO Dennis Muilenburg said the company was "addressing" its safety recommendations. "We commend Indonesia's KNKT for its extensive efforts to determine the facts of this accident, the contributing factors to its cause and recommendations aimed toward our common goal that this never happens again," he said.
The grounding order also caused Boeing to of the Max in January, 2020.
Did Boeing know about Max problems before the crashes?
There is evidence that it did. On Oct. 17, 2019, Boeing between two of the company's top pilots sent in 2016, which indicated the company knew about problems with the MCAS system early on. In one of the messages, a former chief technical pilot for the Boeing 737 described the MCAS' habit of engaging itself as "egregious."
Later that month, two congressional committees, Muilenburg admitted Boeing in early 2019. "I was involved in the document collection process, but I relied on my team to get the documents to the appropriate authorities," he said. "I didn't get the details of the conversation until recently."
Then on Jan. 10, 2020 Boeing and instant messages to Congress in which Boeing employees discussed the 737 Max. Though in getting the aircraft certified -- "I still haven't been forgiven by God for the covering up I did last year," one employee wrote in 2018 -- others openly discussed the 737 Max's flaws . "This airplane is designed by clowns who in turn are supervised by monkeys," another employee wrote. (The New York Times .)
Did Boeing change its leadership?
Yes, but it didn't happen quickly. Though Muilenburg to the victims' families in an interview with in May, 2019, he came under sharp criticism for his response to the crashes. On Oct. 11, 2019, Boeing announced it had so that as CEO, Muilenburg could "focus full time on running the company as it works to return the 737 Max safely to service."
Muilenburg spent the next two months for his resignation from his other position, but on Dec. 23, 2019 the company announced that he had stepped down. "The Board of Directors decided a change in leadership was necessary to restore confidence in the company moving forward as it works to repair relationships with regulators, customers, and all other stakeholders," Boeing . Chairman David Calhoun Muilenburg on Jan. 13, 2020.
Calhoun had defended Muilenburg before taking the top role, but in a March 5, 2020 interview he said his predecessor had needlessly rushed production of the Max before the company was ready. "I'll never be able to judge what motivated Dennis, whether it was a stock price that was going to continue to go up and up, or whether it was just beating the other guy to the next rate increase."
Separately, on Oct. 22, 2019, the company Boeing Commercial Airplanes CEO Kevin McAllister, the official overseeing the 737 Max investigation, with Stan Deal, former president and CEO of Boeing Global Services.