Boeing 737 MAX crisis: a timeline (Part I)

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This article was originally published on AeroTime News on July 22, 2019.

With less than two days left till Boeing reveals their Q2 financial results, the company is due to recognize $5.6 billion fall in revenue for the 2 quarter of 2019 due to the MAX crisis. Constant issues with their fastest-selling narrow-body will place a huge burden on the company’s finances. But the financial results are not the biggest issue here – Boeing is still the biggest producer of aircraft in the world and is more than likely to recover financially when the groundings eventually lift.

When aviation authorities grounded the Boeing 737 MAX in March 2019, the Chicago-based company laid out a clear plan to get the aircraft back in the air: update MCAS, pilot displays, flight manuals and crew training.

But the headlines announcing the grounding extensions, update flaws and the way that the MAX entered service in the first place has placed the aircraft in very dire straits publicly. And the bad image of the newest iteration of the 737 is not something that Boeing can fix with a software update or by changing the supplier of a certain part.

So, when the FAA is yet to establish a clear timeline when the Boeing 737 MAX will return to service and with speculation that we won’t see one flying in the H2 of 2019, the situation raises the question:

How did it all come to this?

The beginnings of the Boeing 737 MAX

There is no secret that the American Airlines’ (A1G) (AAL) narrow-body order in 2011 shocked quite a few people – including Boeing. The manufacturer wanted to make a completely new design so it could finally retire the 50-year-old 737 frame for good. However, American Airlines (A1G) (AAL) presented Boeing with a challenge that it did not want. 

Back in February of the same year, Boeing’s CEO Jim McNerney had a very firm stance about a re-engined 737, as reported by FlightGlobal:

“We’re gonna do a new airplane. We’re not done evaluating this whole situation yet, but our current bias is to not re-engine,” then spoke the head of the American aircraft manufacturer.

However, just four months later, American Airlines (A1G) (AAL) told Boeing what to do: “American also intends to order 100 of Boeing’s expected new evolution of the 737NG, with a new engine that would offer even more significant fuel-efficiency gains over today’s models”.

The manufacturer had nowhere to go – potentially losing options for 100 new 737 jets, especially in the narrow-body segment, was not an option. Boeing was not in the best place financially, as a result of a delay to another aircraft model. The company had to choose:

Either it loses the 100 AA options, which would secure crucial money to offset 787 program losses;

Or it builds a new narrow-body aircraft, potentially running into even more delays down the road and losing even more money.

From an executive point of view, the second option was too risky. The world has just started recovering from the 2008 financial crisis. Boeing was also in a recovery mode – due to lower demand, the manufacturer had lost 6% of revenues in 2010 compared to 2009, according to the company’s financial statement.

The decision to accept the American Airlines (A1G) (AAL) deal bore fruit. Not only Boeing’s revenues were back at 2009 levels, they even surpassed them ($68,281 billion in 2009, $68,735 billion in 2011), but also the 737 MAX was a huge success commercially. 

Commercial success

While American Airlines (A1G) (AAL) ordered a wide variety of 737 models, including the older NG, Southwest Airlines (LUV) one-upped AA. The low-cost carrier gave an early Christmas present to Boeing on December 13, 2011, placing a firm order for 150 Boeing 737 MAX aircraft. At that time, the order broke two records in Boeing’s history. Firstly, it was the most expensive order in monetary terms – the deal was worth almost $19 billion. Secondly, the number of firm aircraft was also record-breaking, as Boeing had never received an order of this scale before.

Even before the 737 MAX took its first breath of fresh air when it was officially unveiled to the world on December 8, 2015, Boeing had already received 2856 total orders for the type. The MAX quickly became Boeing’s best-selling single-aisle aircraft.

Two years later, on May 17, 2017, Boeing completed its first 737 MAX delivery to Malindo Air.


Five days later, Malindo Air operated the world’s first Boeing 737 MAX commercial fight. Flight OD803 took off from Kuala Lumpur to Singapore.

Generally, the mood was great – Boeing escaped a potential financial fiasco, 737 MAX sales were going strong and airlines were extremely happy with the improved efficiency of the new jet.

Turning tide

Not even a full year later, the situation began to shift dramatically.

In the early morning hours on October 29, 2018, a Lion Air Boeing 737 MAX took off on a regularly scheduled flight JT610 from Soekarno–Hatta International Airport in Jakarta to Depati Amir Airport in Pangkal Pinang.

About a minute after taking off, the pilots reported to the Terminal East traffic controller. Shortly after, Lion Air pilots ask for permission to some holding point, as they were having “flight control problems”. 12 minutes after taking off, radars and ATC lost contact with the Lion Air aircraft. The 737 MAX crashed into the sea, taking 189 lives with it.

Initially, people were shocked. The number one question on everybody’s mind was: How could a brand new aircraft, delivered only in August 2018, plunge into the sea?

An automated system to prevent the 737 MAX from stalling

As time passed by, Lion Air CEO revealed that the aircraft had a technical difficulty the previous day, but engineers who worked on it during the night deemed it airworthy to fly on Monday, October 29. Boeing, reacting to the accident, released an Operations Manual Bulletin (OMB) on November 6, 2018. The CEO’s comments and the OMB began to answer some questions, yet at the same time added even more confusion.

The bulletin highlighted “that Lion Air Flight 610 experienced erroneous AOA data,” then Boeing pointed out that during manual flight conditions with erroneous AOA data, the aircraft can commence uncommanded nose-down stabilizer trim movements. In order for pilots to turn off the uncommanded nose-down movements, they have to ensure that both “STAB TRIM CUTOUT switches are moved to CUTOUT”.The OMB also highlighted that erroneous AoA data can, amongst other things, cause an indication of “AOA DISAGREE alert (if the AOA indicator option is installed)”.

But not many MAX pilots were even aware of the automatic system at the time. The Seattle Times published an article on November 12, 2018, just six days after OMB was issued,  reporting that American Airlines (A1G) (AAL) and Southwest Airlines (LUV) pilots were not aware of the automatic system, also known as MCAS. Boeing officially revealed the Maneuvering Characteristics Augmentation System on November 10, 2018, in a Multi Operator Message sent to every airline that operated the MAX/NG. The message provided further insight into how the system works, including the circumstances under which MCAS activates.

However, the methodology that was used to train the pilots that were switching from the NG to the MAX was another detail that caught a lot of attention – according to several sources, pilots only received a 1-hour lecture using iPads. The lecture did not include a session on a simulator.

Lion Air Flight JT610 preliminary report

On November 27, 2018, the Indonesian National Transportation Safety Committee (NTSC) published a preliminary accident report. The report indicated that the same aircraft, registered PK-LQP, had suffered an identical issue the day prior to the deadly crash. The flight captain noticed that as soon as the first officer stopped putting trim input, MCAS would activate and push the aircraft’s nose down. After three such automatic movements, the captain moved the STAB TRIM switches to CUT OUT.

Boeing’s OMB also indicates the same plan of action to counteract MCAS. However, the fact that the Lion Air Boeing 737 MAX did not crash the day before was a case of the right circumstances coming together, as the OMB was only available after Flight 610 crashed.

In addition, Bloomberg reported on March 20, 2019, that a third pilot was present in the cockpit during the flight where the pilots managed to disable automatic nose-down movements, saving the aircraft from a disaster.

Nevertheless, the preliminary report showcased that the pilots on the doomed Lion Air flight were constantly engaged in a David versus Goliath fight. Unfortunately, the Goliath, that was the Boeing 737 MAX equipped with MCAS, won. The investigators also noted that the Digital Flight Data Recorder showcased a difference of 20° between the left and right Angle of Attack sensors.

Highlighting maintenance and culture

Indonesian investigators and Boeing both highlighted maintenance issues. The NTSC report included specified safety recommendations, one of which indicated that the aircraft was in an unairworthy condition, as a result of the continuous stick shaker activity present throughout the whole duration of the flight the day prior to the deadly accident. Furthermore, the NTSC also suggested Lion Air to “improve the safety culture and to enable the pilot to make proper decision to continue the flight”.

Boeing added further comments regarding the maintenance procedures done on the 737 MAX: “The report does not include records as to the installation or calibration of the new sensor, nor does the report indicate whether the sensor was new or refurbished.  Although the report states that the pilot was satisfied by the information relayed by the engineer that the AOA sensor had been replaced and tested, on the subsequent flight [Lion Air Flight JT610 – ed. note] the pilots again experienced problems with erroneous airspeed data, and also experienced automatic nose-down trim”.

The manufacturer used the opportunity to also call out the performance of pilots on the fatal flight. “Unlike as is stated with respect to the prior flight, the report does not state whether the pilots performed the runaway stabilizer procedure or cut out the stabilizer trim switches”.

Additionally, as highlighted by the Indonesian NTSC report, the airline passed on the safety instruction regarding erroneous AOA data on November 8, 2018, much later than the accident.

A third pilot on a flight on October 28, 2018, a day before the crash, saved the same Boeing 737 MAX from plunging into the ground, which begs two questions: can Boeing blame the pilots, when the manufacturer himself did not include crucial information about the software onboard the aircraft? And was a crash that involved a Boeing 737 MAX inevitable?

An update within weeks

As reported exclusively by Reuters on November 30, 2018, Boeing was lingering whether to update MCAS. The update would have allowed the pilots to override the software manually by “trimming or adjusting settings in the opposite direction,” while also checking data from both AOA sensors from the aircraft.

The primary plan was to launch the update within six to eight weeks, which means that the update was meant to come in January of 2019.

Nevertheless, the update never came.

On March 11, 2019, a day after the Ethiopian Airlines Flight ET302 crash, Boeing confirmed working on an update related to MCAS, flight manuals and crew training. FAA, according to Boeing, expected the updated 737 MAX software to come out no later than April.


However, if MAX operators received the Operations Manual Bulletin on how to stop MCAS from going rampant with the flight controls, then why did the Ethiopian Airlines Flight ET302 crash?
































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