On Oct. 29, 2018, Lion Air Flight 610 crashed minutes after takeoff from Jakarta, Indonesia, killing all 189 people on board. Four months later, on March 10, 2019, Ethiopian Airlines Flight 302 crashed shortly after takeoff, killing its 157 passengers and crew. The common link? Both flights were operated by Boeing's 737 MAX 8 aircraft.
An investigation into the two fatal crashes revealed a series of problems with the aircraft’s software, overlooked by both Boeing and the Federal Aviation Administration (FAA), which ultimately led to the worldwide grounding of the 737 MAX. Today, the FAA has lifted that flight ban in the United States, deeming that Boeing's safety upgrades to the aircraft are sufficient. The 20-month ban is officially the longest grounding of a U.S. airliner in history, and it cost Boeing more than $18 billion in lost revenue.
But does that mean the aircraft, which is one of the most popular in the world, will imminently return to the skies? Well, not quite. Here's what you need to know.
What Happened with the Boeing 737 MAX?
The first Boeing 737 aircraft entered service in 1968, and since then, more than 10,500 planes have been built—it’s the short-haul workhorse of many airlines around the world. The 737 MAX is the newest model in the family, debuting commercially in 2017 and quickly becoming Boeing’s fastest-selling plane.
But that all came to a very dramatic halt after the fatal crashes. “Accidents in aviation do not happen due to a single failure,” said José Godoy, the chief commercial officer of flight operations company Simpfly. “It is usually due to an unfortunate alignment of bad or imprecise decisions. And the case of the 737 MAX is no different.”
At their core, both crashes had to do with a new software system in aircraft called the Maneuvering Characteristics Augmentation System (MCAS), which was initially designed to help make the aircraft handle more similarly to its predecessor, the 737 Next Generation (737NG). Specifically, MCAS automatically corrects the aircraft’s potential to stall due to its engines' size and placement.
“Boeing decided to implement such an automatic system with the main goal of making the 737 MAX behavior to be the same as the 737NG, so no further training would be needed for pilots that already fly the 737NG,” Godoy said. “However, for that, Boeing omitted the existence of this system in the airplane manual, so pilots were not aware of it at all, with no coverage in training. That was also overlooked by the FAA during MAX certification.”
So when the pilots of Lion Air Flight 610 and Ethiopian Airlines Flight 302 encountered the MCAS system’s activation—which in itself had to do with incorrect data from angle-of-attack (AoA) sensors—they were unprepared, taking what they thought were the correct steps to rectify the problem, but ultimately making a fatal miscalculation.
But that was only part of the problem. During production and certification, Boeing reportedly downplayed the MCAS system's significance and swept concerns about its safety under the rug. At the same time, the FAA overlooked these issues when certifying the aircraft. Thus the cause of the crashes combines these coverups, the faulty AoA sensor readings, and the pilots’ lack of knowledge about the MCAS system.
How Boeing Fixed the 737 MAX
To fix the problems with the 737 MAX, Boeing has overhauled the MCAS software (plus some hardware in the aircraft) to include extra redundancies for safety and updated its pilot training procedures for the aircraft, all under the oversight of numerous global regulators, with input from an independent board of experts from various organizations, including NASA and the U.S. Air Force. (If you’re curious as to all the specifics, the FAA published the full list of steps Boeing must take to fix the aircraft before it’s allowed to fly again—and you bet Boeing will comply with them.)
“Once the FAA and other regulators have determined the MAX can safely return to service, it will be one of the most thoroughly scrutinized aircraft in history, and we have full confidence in its safety,” Boeing said in a statement. “We have also taken steps to bolster safety across our company, consulting outside experts, and learning from best practices in other industries.”
The 737 MAX's Return to Service
While Boeing initially hoped that the 737 MAX would fly by the end of 2019, the aircraft still has a long road ahead of it. While the FAA's recertification is a huge step forward, there are still several boxes to tick before the plane starts flying.
First, the FAA only has jurisdiction over domestic flights in the U.S. While technically the plane is now allowed to fly in American airspace, every single 737 MAX aircraft will need to undergo inspections before taking off, and pilots must undergo special training.
Additionally, international operations of the 737 MAX must still be approved by foreign regulators—but it seems that those approvals are forthcoming. The European Union Aviation Safety Agency (EASA) is getting ready to recertify the aircraft, according to a Bloomberg interview with Patrick Ky, EASA's executive director. In that interview, Ky asserted his full confidence in the safety of the 737 MAX.
And given the FAA's approval, it's likely that other international regulators will soon follow suit in recertifying the aircraft. “By convention, aviation regulators worldwide accept the certification of aircraft from the country of manufacture and do not review those certifications in much detail,” says Godoy. “However, due to these specific events, several aviation authorities—particularly EASA—decided to conduct their own assessments and validation tests of the MAX before authorizing it in their controlled airspace.”
While Ky is confident in the 737 MAX, EASA as an entity has requested further changes to the aircraft that will likely take up to two years to implement, though it would approve the plane to fly long before then.
In the meantime, airlines are already attempting to drum up the public’s support of the aircraft. American Airlines plans to offer tours of its 737 MAX aircraft in Dallas, Miami, and New York, alongside Q&A sessions with pilots and engineers, in anticipation of bringing the aircraft back into limited service by the end of the year.
“We are seeing that finish line approach us, and I think it’s a real finish line,” American Airlines’ chief operating officer David Seymour said in a town hall meeting last week, according to CNBC.
The other two major U.S.–based airlines that have 737 MAX aircraft in their fleet are United and Southwest, who both plan to reintroduce the plane in early 2021.