Lion B38M near Jakarta on Oct 29th 2018, aircraft lost height and crashed into Java Sea, wrong AoA data

Last Update: September 16, 2020 / 13:36:36 GMT/Zulu time

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Incident Facts

Date of incident
Oct 29, 2018


Aircraft Registration

Aircraft Type
Boeing 737-800MAX

ICAO Type Designator

On Sep 16th 2020 the Committe on Transportation and Infrastructure of the United States House of Representatives released their final report of 238 pages into the safety cultures of both Boeing and FAA which led to the crashes of both Lionair's Boeing 737-8 Max and Ethiopian Airlines' Boeing 737-8 Max. The Committee concluded:

Time for a Culture Change

Both Boeing and the FAA share responsibility for the development and ultimate certification of an aircraft that was unsafe. Both must learn critical lessons from these tragic accidents to improve the certification process, and the FAA must dramatically amplify and improve its oversight of Boeing. While the changes that the FAA and Boeing have proposed will be the start of a long process, changing the fundamental cultural issues that led to an environment that permitted Boeing to build, and FAA to certify, a technologically faulty aircraft will take much longer.

The Committee continued the conclusions:

Do Things Right and Do the Right Thing

One of the fundamental canons for engineers is that they hold paramount the safety, health, and welfare of the public. Or as Texas State University Engineering Professor Karl Stephan says, “A good engineer both does things right, and does the right thing.” In the case of the 737 MAX, unfortunately, Boeing failed to meet both criteria. It did not do things “right” when it designed MCAS, for instance. It failed to build in essential redundancies by permitting MCAS to rely on a single AOA sensor. It allowed MCAS to activate repetitively, although at least one Boeing engineer had raised concerns about that capability. And it did not appropriately address the question of faulty AOA data and the negative implications for MCAS because a Boeing engineer falsely assumed that MCAS would not allow that to happen and “shut down.” That did not happen in either of the MAX crashes.

Furthermore, Boeing did not do the “right thing” when it removed references to MCAS from the pilot’s Flight Crew Operations Manual (FCOM). Without question, it was not right for Boeing to fail to share with the FAA Boeing’s own test data showing that it had taken a test pilot more than 10 seconds to respond to uncommanded MCAS activation, and the test pilot believed the condition was “catastrophic[.]” Nor did Boeing do the “right thing” when it became aware that the AOA Disagree alert was not functioning on more than 80 percent of the 737 MAX fleet and then failed to alert the FAA, its customers, and MAX pilots while it continued to both manufacture and deliver an estimated 200 airplanes with this known nonfunctional component.

In the weeks after the Lion Air crash, Boeing defended its development and certification of MCAS to the FAA, writing that there was “no process violation or non-compliance” regarding the inconsistencies in the system’s development and Boeing’s actions, including (1) removing reference to MCAS from the FCOM, (2) determining “repeated unintended MCAS” activation to be no worse than a single unintended activation, (3) determining the loss of one AOA sensor followed by erroneous readings from the other AOA sensor to be extremely remote and not analyzing this scenario in its failure assessments, and (4) not reassessing failure analyses following the MCAS design change.

The FAA’s own draft review of MCAS in the wake of the Lion Air crash also found no “non-compliances” with FAA regulations on the part of Boeing.1370 The fact that multiple technical design missteps or certification blunders were deemed compliant by the FAA points to a critical need for legislative and regulatory reforms. That Boeing was able to show that its new transport category commercial aircraft met the FAA’s certification criteria, yet was involved in two fatal crashes within the span of just two years and two days after the FAA granted certification, is disconcerting. The FAA’s aviation oversight system failed in dramatic fashion. This sentiment is underscored by Tommaso Sgobba, Executive Director of the International Association for the Advancement of Space Safety (IAASS), who recently observed: “The Boeing B-737 MAX accidents represent a major failure of the aviation regulatory system….” Indeed, producing a compliant aircraft that proved unsafe should have been an immediate wake-up call to both Boeing and the FAA that the current regulatory system that certified the MAX is broken. Unfortunately, serious questions remain as to whether Boeing and the FAA have fully and correctly learned the lessons from the MAX failures.

The Once Great Engineering Firm

The beginning of this report quoted Harry Stonecipher, the Chief Executive Officer of McDonnell Douglas who became the President and Chief Operating Officer of Boeing, who in 2004 told the Chicago Tribune: “When people say I changed the culture of Boeing, that was the intent, so it’s run like a business rather than a great engineering firm.” It is unfortunate that many current and former Boeing employees the Committee has spoken to during this investigation believe Boeing has succeeded in meeting that goal. They understand they once worked for a great engineering firm, and many hope that they will again in the future. But they realize this will happen only if Boeing begins to refocus its engineering expertise on building great, safe aircraft, and that this endeavor will be a long-term challenge.

This report’s main investigative findings point to a company culture that is in serious need of a safety reset. Boeing has gone from being a great engineering company to being a big business focused on financial success. Continuing on the same path it followed with the 737 MAX, where safety was sacrificed to production pressures, exposes the company to potentially repeating those mistakes and to additional reputational damage and financial losses. One of the first steps on a new path is understanding and acknowledging the problems that did occur, the technical mistakes that were made, and the management missteps that led to the 737 MAX tragedies and the preventable death of 346 people.

However, the Committee’s investigation leaves open the question of Boeing’s willingness to admit to and learn from the company’s mistakes. In a transcribed interview with Committee staff, Keith Leverkuhn, the former senior-most official on Boeing’s 737 MAX program, who is now Vice President of Supply Chain Propulsion for Boeing Commercial Airplanes, appeared unable or unwilling to either take responsibility for any of the problems that occurred on the MAX program or to even acknowledge that any problems existed at all.

T&I Committee staff: "In light of the two crashes and the fact that
the MAX has been grounded for more than a year, would you
consider the development of the MAX a success?"
Mr. Leverkuhn: "Yes, I would. ...
... I do challenge the suggestion that the development [of the 737
MAX] was a failure."

Several weeks before this report was finalized, multiple news stories suggested that Boeing was endeavoring to change the name of the 737 MAX to the 737-8 in an effort to combat the indelible image problems now surrounding the aircraft. If the Committee’s investigation offers any lessons for Boeing, it is that a name change and a public relations effort will not address the cultural issues at Boeing that hampered the safety of the 737 MAX in the first place and ultimately led to two fatal accidents and the death of 346 people. A name change may help confront a public relations problem, but only a genuine, holistic, and assertive commitment to changing the cultural issues unearthed in the Committee’s investigation at both Boeing and the FAA can enhance aviation safety and truly help both Boeing and the FAA learn from the dire lessons of the 737 MAX tragedies.

The Committee summarized the sequence of events leading to the crash of JT-610:

The day before the crash of Lion Air flight 610, a mechanic in Denpasar, Indonesia, replaced the AOA sensor on the left side of the accident airplane, prior to its 90-minute flight from Denpasar to Jakarta.30 The mechanic used a refurbished AOA sensor that had previously been used on a Boeing 737-900ER (NG) aircraft operated by Lion Air’s Malaysian sister company, Malindo Air, and rebuilt in late 2017 by Xtra Aerospace in Miramar, Florida.

On the flight to Jakarta, MCAS activated based on an erroneous reading from the newly installed AOA sensor and commanded the airplane’s horizontal stabilizer33 to push the nose down while the pilots struggled against it to stabilize the airplane.34 In this case, a third “deadheading” pilot who occupied the jump seat inside the flight deck35 recognized what was occurring and provided instructions to the two active pilots that enabled them to regain control of the airplane and fly it safely to Jakarta by depressing two “stabilizer trim cutout” switches, thereby removing electrical power from the flight control that MCAS was erroneously activating.

Upon landing in Jakarta, the captain made entries in the airplane’s maintenance log about cautions and warnings that appeared during the flight. However, he did not report the flight crew’s use of the stabilizer trim cutout switches to address the unexpected horizontal stabilizer movement.

On the following day, October 29, 2018, Lion Air flight 610 departed Jakarta. Again, the AOA sensor provided inaccurate information to the flight control computer which triggered MCAS to move the horizontal stabilizer which pushed the airplane’s nose down.38 This occurred more than 20 times as the pilots fought MCAS while struggling to maintain control of the aircraft. Unfortunately, because the previous flight crew did not document its use of the stabilizer trim cutout switches to address the same condition, the new flight crew did not have an important piece of information that could have helped them to identify and respond to the problem. Amid a cacophony of confusing warnings and alerts on the flight deck, the horizontal stabilizer ultimately forced the airplane into a nose-down attitude from which the pilots were unable to recover.

THe Committee summarized the events leading to the crash of ET-302:

Nearly five months later, on March 10, 2019, once again a faulty AOA sensor and subsequent triggering of MCAS led to the downing of Ethiopian Airlines flight 302. As opposed to the Lion Air accident airplane on which cautions and warnings on its earlier flights had given some indication of a problem, the 737 MAX operated by Ethiopian Airlines had no known technical troubles.42 However, after a normal takeoff, the left AOA sensor began producing erroneous readings.

Over the approximately six minutes that Ethiopian Airlines flight 302 was airborne following its departure from Addis Ababa, Ethiopia, MCAS triggered four times as a result of the false AOA readings and caused the airplane’s horizontal stabilizer to force the airplane into a nose down attitude from which the pilots were unable to recover. Faulty AOA data that erroneously triggered MCAS to repeatedly activate played critical roles in both MAX crashes.

The Committee adressed concerns over maintenance and training of pilots as follows:

There have been some allegations made against both Lion Air and Ethiopian Airlines regarding poor maintenance and even cover-ups. For example, investigators determined that photos provided by the Lion Air mechanic that purported to document the AOA sensor repair on the accident airplane depicted a different airplane and dismissed the photos as invalid evidence. In addition, a whistleblower with knowledge of Ethiopian Airlines’ actions in the aftermath of the March 2019 crash alleged that staff of the carrier accessed the airplane’s maintenance records the day after the accident.

Such action is contrary to protocols that call for records to be immediately sealed following a crash. However, while it is not known how, if at all, the records were altered, the whistleblower contends that this action was part of a pattern of faulty repairs and erroneous records that call into question the reliability of Ethiopian Airlines’ maintenance practices.

In addition to maintenance concerns, some negative aspersions have arisen about the abilities of the pilots who commanded the ill-fated Lion Air and Ethiopian Airlines flights. While Lion Air has a reputation for hiring inexperienced pilots and quickly promoting them, the 31-yearold captain of Lion Air flight 610 had accumulated over 5,100 hours of flight time on Boeing 737 airplanes, and the 41-year-old first officer had more than 4,200 hours on Boeing 737 models, indicating that they were seasoned pilots. Further, while the 29-year-old captain of Ethiopian Airlines flight 302 had reportedly not received training on the airline’s 737 MAX simulator—even though Ethiopian Airlines was one of the first airlines worldwide to purchase a 737 MAX specific simulator—the young pilot had amassed over 5,500 flying hours on Boeing 737 airplanes, including 103 hours on the 737 MAX. Even the 25-year-old first officer of flight 302—who was the least experienced of the pilots—had accumulated 207 hours flying Boeing 737 airplanes since obtaining his commercial pilot’s license in December 2018, just three months before the fatal crash.

Addressing the qualifications of these pilots at a June 2019 Subcommittee on Aviation hearing, Captain Dan Carey, a 35-year career pilot and then president of the Allied Pilots Association, which represents 15,000 American Airlines pilots, said in his written statement:

"To make the claim that these accidents would not happen to U.S.-
trained pilots is presumptuous and not supported by fact. Vilifying non-U.S. pilots is disrespectful and not solution-based, nor is it in line with a sorely needed global safety culture that delivers one standard of safety and training. Simply put, Boeing does not produce aircraft for U.S. pilots vs. pilots from the rest of the world."

Retired airline captain Chesley B. “Sully” Sullenberger III, who landed U.S. Airways flight 1549 on the Hudson River in 2009 saving all 155 people on board in what came to be known as the “Miracle on the Hudson,” also testified at that hearing. He offered similar sentiments about the qualifications of these pilots as part of his remarks about the two crashes. In his prepared testimony Captain Sullenberger wrote:

"These crashes are demonstrable evidence that our current system of aircraft design and certification has failed us… It is obvious that grave errors were made that have had grave consequences, claiming 346 lives… Accidents are the end result of a causal chain of events, and in the case of the Boeing 737 MAX, the chain began with decisions that had been made years before, to update a half-century-old design… We owe it to everyone who flies, passengers and crews alike, to do much better than to design aircraft with inherent flaws that we intend pilots will have to compensate for and overcome. Pilots must be able to handle an unexpected emergency and still keep their passengers and crew safe, but we should first design aircraft for them to fly that do not have inadvertent traps set for them."

For two brand-new airplanes, of a brand-new derivative model, to crash within five months of each other was extraordinary given significant advances in aviation safety over the last two decades. While certain facts and circumstances surrounding the accidents differed, a common component in both of the accident airplanes was the new flight control feature: MCAS. Boeing developed MCAS to address stability issues in certain flight conditions induced by the plane’s new, larger engines, and their relative placement on the 737 MAX aircraft compared to the engines’ placement on the 737 NG. On March 13, 2019, the FAA grounded the 737 MAX three days after the Ethiopian Airlines crash, following similar actions taken by China, the EU, and Canada, among others. Despite optimistic predictions at the time—that a simple software fix for MCAS would allow the 737 MAX to return quickly to service —the aircraft has been grounded for 18 months, with even more, newly discovered safety issues emerging since. (See “New Issues Emerge” below).
Incident Facts

Date of incident
Oct 29, 2018


Aircraft Registration

Aircraft Type
Boeing 737-800MAX

ICAO Type Designator

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