When Will the 737 Max Fly Again and 9 Other Questions About Boeing’s Troubled Plane

December 17, 2019, 12:30 PM UTC

Two crashes within five months — Lion Air Flight 610 in October 2018 off the coast of Indonesia and Ethiopian Airlines Flight 302 in March outside Addis Ababa — killed 346 people and led to a global grounding of Boeing Co.’s 737 Max jets, the fourth generation of a venerable brand first flown in 1967. Uncertainty over when it will fly again is rippling through the airline industry and Boeing’s finances. The U.S. manufacturer’s bill is $9.2 billion and rising, as it faces questions about the plane’s development and its own transparency.

1. When will the 737 Max fly again?

Unclear. Boeing had hoped the single-aisle plane would be back in service by the end of 2019, but that’s not going to happen. The U.S. Federal Aviation Administration must first certify redesigned flight-control software that’s supposed to address the cause of the two crashes. Regulators also must sign off on updated training material for pilots. It also will take time for airlines to ready stored jets for service and work them back into flight schedules.

2. Will air travelers get back on board?

In an April survey led by consultant Henry Harteveldt, 20% of U.S. travelers said they would definitely avoid the plane in the first six months after flights resume. More than 40% said they’d even take pricier or less convenient flights to stay off the Max. A June survey by UBS Group AG found 12% of respondents saying “no amount of safe operation will alleviate their concerns” about flying on the 737 Max. To boost public confidence, American says its executives and other staff will take the first flights, before paying passengers, as soon as the Max is certified fit to fly.

3. How many 737 Maxes are out there?

Before the crashes, Boeing reported 387 deliveries to 48 airlines or leasing companies, with orders from around 80 operators for 4,406 more. Southwest says it has 34 in its fleet; American and Air Canada each have 24. Chinese airlines account for about 20% of 737 Max deliveries globally, most of them the Max 8, the model involved in both crashes. (There’s also, from smallest to biggest, a Max 7, 9 and 10.) Since the grounding in March, Boeing’s factory in Renton, Washington, continued to churn out 42 of the jets a month, though the company isn’t allowed to deliver the aircraft while the flying ban remains in place. So Boeing placed more than 380 newly built planes in storage, according to a tally by blogger Chris Edwards, before deciding in December to suspend production indefinitely.

SEATTLE, WA - MAY 31: The tails of Boeing 737 MAX airplanes are seen as they sit parked at a Boeing facility adjacent to King County International Airport, known as Boeing Field, on May 31, 2019 in Seattle, Washington. Boeing 737 MAX airplanes have been grounded following two fatal crashes in which 346 passengers and crew were killed in October 2018 and March 2019. (Photo by David Ryder/Getty Images)
The tails of Boeing 737 MAX airplanes are seen as they sit parked at a Boeing facility adjacent to King County International Airport, known as Boeing Field, on May 31, 2019 in Seattle, Wash.
David Ryder—Getty Images

4. What has this meant for the airline industry?

Far more jets were in Boeing’s order backlog than in service. Ryanair Holdings Plc said it was scaling back growth plans for mid-2020 because it’s likely to get barely half of the 58 Max planes it was expecting. American said it’s canceling about 140 flights a day; at Southwest, that number is 200 on an average weekday. TUI AG, the world’s largest tourism service company, said a profit rebound was wiped out by the grounding of its 15 Max aircraft. Uncertainty over when Boeing will restart production adds to the strain at suppliers — and any job cuts at those companies may later impede the planemaker’s own recovery.

5. What has this meant for Boeing?

In April, the Chicago-based company abandoned its financial forecast for 2019 and missed its quarterly earnings estimates for just the second time in five years. In the third quarter, it posted its largest cash burn in almost 25 years. Boeing revealed in July that it had taken a $5.6 billion pretax writedown to cover potential costs incurred by airline customers due to the grounding; already, Indian budget carrier SpiceJet Ltd. has booked income it expects to receive as compensation. Saudi Arabia’s Flyadeal in July became the first airline to officially drop the 737 Max, reversing a commitment to buy as many as 50. Virgin Australia has pushed back delivery of its first 737 Max jets by almost two years. There’s also the prospect of substantial payouts to the families of passengers if Boeing is found responsible for the crashes.

RENTON, WA - DECEMBER 16: The Boeing 737 factory is seen on December 16, 2019 in Renton, Washington. The company announced it is suspending production of the plane, which has been grounded since early 2019 after two crashes, in January 2020. (Photo by Stephen Brashear/Getty Images)
The Boeing 737 factory is seen on Dec. 16, 2019 in Renton, Wash. The company announced it is suspending production of the plane, which has been grounded since early 2019 after two crashes, in January 2020.
Stephen Brashear—Getty Images

6. Any fallout at the top?

Some. The head of Boeing’s jetliner division, Kevin McAllister, stepped down. Chief Executive Officer Dennis Muilenburg was stripped of his role as chairman and will waive his 2019 bonus. He faced a grilling by U.S. lawmakers and numerous calls to resign during two days of often contentious hearings in October. At a conference a week later, he said he considered stepping down but decided to stay on. On Dec. 12 FAA Administrator Steve Dickson publicly criticized Muilenburg for pursuing what the agency called an unrealistic schedule for the Max’s return to service.

7. What does Boeing say?

Muilenburg has apologized for the accidents and said the situation “will continue to weigh heavily on our hearts and on our minds for years to come.” The company has said it is committed to addressing “all the FAA’s questions” and thinks the 737 Max will eventually regain its position as the backbone of its single-aisle fleet.

8. What legal action could Boeing face?

Claims have been filed by families of crash victims. Bloomberg Intelligence estimates Boeing’s litigation risks in the U.S. could amount to $1 billion. Boeing offered $100 million over several years as an “initial outreach” to support the families of victims and others affected, and hired high-profile mediator Kenneth Feinberg to distribute it. On other legal fronts, the U.S. Justice Department expanded its probe to include a look into manufacturing of another Boeing aircraft — the 787 Dreamliner — at a new plant in South Carolina. The U.S. Securities and Exchange Commission is investigating whether Boeing properly disclosed issues tied to the 737 Max jetliners to investors. And Boeing faces proposed class action lawsuits by pilots.

9. What do people think caused the crashes?

In both cases, pilots were likely overwhelmed by a new flight control feature added to the Max known as the Maneuvering Characteristics Augmentation System, or MCAS. It activates when the plane appears to be at risk of stalling, a situation in which the wings are losing lift because the jet is climbing too steeply. The use of new, bigger engines on the 737 Max required Boeing’s designers to mount the turbines farther forward on the wings to give them proper ground clearance. That changed the plane’s center of gravity. In the two crashes, MCAS kicked on due to an erroneous sensor reading and pushed the plane’s nose downward. After a rocky trial of the MCAS software in 2016, one senior Boeing pilot called the handling performance “egregious.” The crash report by Indonesia’s National Transportation Safety Committee also blamed a failure to adequately consider the human equation and how pilots respond to a fast-moving emergency in a chaotic cockpit.

Priests hold a ceremony beside coffins of victims of the crashed accident of Ethiopian Airlines during the mass funeral at Holy Trinity Cathedral in Addis Ababa, Ethiopia, on March 17, 2019. - The crash of Flight ET 302 minutes into its flight to Nairobi on March 10 killed 157 people onboard and caused the worldwide grounding of the Boeing 737 MAX 8 aircraft model involved in the disaster. (Photo by Samuel HABTAB / AFP) (Photo credit should read SAMUEL HABTAB/AFP via Getty Images)
Priests hold a ceremony beside coffins of victims of the crash of Ethiopian Airlines flight 302, in Addis Ababa, Ethiopia, on March 17, 2019. The crash of Flight 302 on killed 157 people onboard and caused the worldwide grounding of the Boeing 737 Max 8 aircraft model involved in the disaster.
SAMUEL HABTAB—AFP via Getty Images

10. Who approved this system?

The FAA gave final certification to the 737 Max in March 2017, and it entered commercial service two months later. Under a program established in 2005, the FAA had delegated to Boeing the authority to perform some safety-certification work on its behalf. Some FAA employees warned as far back as 2012 that Boeing had too much sway over safety approvals of new aircraft. Boeing said in May that it had known months before the Indonesia crash that the cockpit alert wasn’t working the way it had told buyers, but it didn’t share that with airlines or the FAA until after the Lion Air jet went down.

More must-read stories from Fortune:

China’s big blockchain bet aims for an early advantage over the U.S.
2020 Crystal Ball: Predictions for the economy, politics, technology, etc.
—China’s lessons from the bike sharing bust may hang over its A.I. boom
Arsenal star’s Uighur comments risk another league’s China business
—Why it’s still so hard to sell medical marijuana in Asia
Catch up with Data Sheet, Fortune’s daily digest on the business of tech.