I've covered Boeing's 737 MAX for years. A quick rundown of the issues | Cruising Altitude

Corrections and Clarifications: Boeing’s MAX is the company’s fourth generation of 737s.

Issues with the Boeing 737 MAX family of jets have defined my career as an aviation reporter.

I cut my teeth at The New York Times following the saga of two of the new jets that crashed within six months of each other in 2018 and 2019, killing 346 people between the incidents.

In the years since, a slow trickle of MAX news has served as mileposts in my career. I’ve had the chance to cover the airplane program at virtually every outlet I’ve written for since those first crashes, and so when I saw the news about Alaska Airlines flight 1282 – which lost a door plug midflight on Friday evening – I knew it was another chapter for both the plane and me.

The MAX is the company’s bestselling jet of all time, but it’s been a thorn in the company’s side. There’s steep competition for efficient single-aisle planes with Airbus, Boeing’s main competitor and manufacturer of the equally popular A320 family of planes. New efficiencies in recent generations of the Airbus led Boeing to develop the MAX in the first place.

Seeing this latest MAX incident left me wondering first whether the plane was safe, and then, whether its reputation would ever recover.

Experts assure me the answer to both questions is yes.

“The immediate response by the (Federal Aviation Administration) and the manufacturer and the airlines was to instantly ground those particular models of aircraft that have this type of configuration,” Laura Einsetler, a pilot for a major U.S. airline and author of the Captain Laura blog told me. “Once this situation is remedied and they can find the cause, the root source cause, the fact that the safety record has been so good to this point, it’s not a concern of mine that the aircraft will continue to be very safe and secure for passengers and crew.”

Einsetler is qualified to fly Boeing 737 MAX planes, though she’s working on 757 and 767 aircraft.

Richard Aboulafia, an aviation analyst and managing director at Aerodynamic Advisory, said he’s confident the issue with MAX jets will be addressed quickly and have little impact on customer confidence.

“The question most people ask these days is how quickly can they resume ramping up MAX production and I don’t think this will be a major crimp in that,” he said. “At the end of the day, airlines are keeping the faith.”

Even so, it felt like a good time to take stock of the 737 MAX’s history. And I’ll confess that in the back of my mind, I still wonder if the jet’s reputation will ever really recover.

The FAA announced on Tuesday that the affected planes would remain grounded indefinitely as inspection and remediation procedures are ironed out.

Boeing 737 MAX development

Airbus announced a more efficient version of its popular A320 single-aisle family, the A320neo, in 2010. Airlines, constantly looking for cost savings in a tight-margin business, were eager to try out the jet and orders began stacking up. That put Boeing behind its main competitor, leaving them with a decision: should they produce another generation of their bestselling 737 or start fresh with a new design, rather than relying on an airframe developed as a workhorse in the 1960s?

Ultimately, the question came down to cost. It was cheaper to stretch and redesign the existing plane than to start from scratch, and faster development was a competitive advantage. So, Boeing unveiled its plans for the 737 MAX, an update to its venerable family of short-to-mid-range jets. The MAX would have larger, more efficient engines and be able to accommodate more passengers than earlier generations of the 737. But those bigger engines posed a problem for Boeing. They changed the aerodynamics of the plane, which could have wiped out some of the efficiencies Boeing was hoping to deliver.

Different aerodynamics mean different flying characteristics and different flying characteristics meant that pilots could be required to undergo costly training to fly the newest 737s. To stay competitive, Boeing needed to make the new jets fly like their older cousins. If pilots had to get retrained, the cost-savings of keeping the 737 going would likely be erased, or at least greatly eroded.

The development of MCAS

To keep the newest 737s feeling familiar to pilots, Boeing developed software called the maneuvering characteristics augmentation system, or MCAS. It automatically compensated for the changed aerodynamics of the new jets. But Boeing applied to the FAA to leave any mention of the system out of the pilot manual, and that application was approved. The plane was flying for more than a year before most pilots even knew MCAS existed.

Lion Air 737 MAX crash

The first major incident for Boeing’s 737 MAX family was the crash of Lion Air Flight 610 on Oct. 29, 2018. The MAX 8 operating that flight plunged into the Java Sea shortly after taking off from Jakarta, killing all 189 people on board.

Boeing initially hesitated to identify MCAS as a contributor to the crash, but some details of the system’s performance emerged within days of the incident. By early November, the team I was working on at The Times was reporting on how flight control software may have contributed to the crash.

Even so, the plane kept flying.

Ethiopian Airlines 737 MAX crash

Months later, on March 11, 2019, another 737 MAX 8 crashed shortly after takeoff. Ethiopian Airlines flight 302 was heading from Addis Ababa, Ethiopia, to Nairobi, Kenya, when MCAS again activated shortly after takeoff, pushing the plane to the ground and killing all 157 people on board.

The FAA did not ground the U.S. fleet of MAX jets until March 13, but that order ultimately stayed in force until Nov. 18, 2020.

Warning signs at Boeing

While the planes were grounded, a trove of internal Boeing documents was released. By that time, I was writing for The Points Guy and still covering the story.

Among the revelations: Lion Air had specifically asked Boeing to include a training mandate for the new aircraft, which Boeing officials still feared could tarnish the program.

In an instant message between employees that was distributed in a June 2017 email, more than a year before the fatal Lion Air crash, one Boeing worker said, "Now frigging Lion Air might need a sim to fly the MAX, and maybe because of their own stupidity. I'm scrambling trying to figure out how to unscrew this now!"

What caused the crashes

In both MAX crashes, MCAS was identified as a key cause. Flaws in its design, including relying on data from only one sensor and the decision not to notify pilots of its existence, all but doomed the Lion Air and Ethiopian flights.

When the MAX family of jets returned to the skies in November 2020, regulators assured the public that the planes were safe and that issues with MCAS had been rectified, but many travelers swore they would never fly the plane.

The latest 737 MAX incident

For Boeing, Alaska Airlines flight 1282’s explosive decompression was surely an unwelcome development.

While the safety record of the MAX has been fine since it returned to service in 2020, the cloud of the plane’s early career disasters continues to shadow the program.

It’s worth noting that the plane involved in Friday’s incident was a MAX 9, a slightly larger version than the MAX 8s that operated the infamous Lion Air and Ethiopian flights.

The issue on Friday has been identified as a poorly installed plug over a spot that could accommodate an extra emergency exit in certain aircraft configurations. Early inspections by U.S. airlines have already revealed similar faults in other MAX 9s, suggesting that it was only a matter of time before a flight experienced this kind of failure.

The FAA has ordered airlines to stop flying some of their MAX 9s until the jets can be inspected and any door plug issues remedied, but I have to imagine that even if the planes soon return to the skies, Boeing executives may continue to worry about what other shoes may yet drop on this family of aircraft.

Graphics by Karl Gelles, Ramon Padilla, George Petras, Janet Loehrke, USA TODAY

Zach Wichter is a travel reporter for USA TODAY based in New York. You can reach him at zwichter@usatoday.com

This article originally appeared on USA TODAY: Taking stock of the Boeing 737 MAX over the years | Cruising Altitude