Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- JetZero readies effort for private equity fund raising May 5, 2025
- Bjorn’s Corner: Air Transport’s route to 2050. Part 20. May 2, 2025
- Supplier Howmet exceeds expectations despite tariffs May 1, 2025
- Airbus 1Q2025 results: So far, so good, but US tariffs make future results unpredictable May 1, 2025
- Does an Airbus A220-500 need a new wing and engines? May 1, 2025
NTSB issues critique of Ethiopia’s final report of Boeing 737 MAX 2019 crash
By Scott Hamilton
Dec. 27, 2022, © Leeham News: The US National Transportation Safety Board (NTSB) today issued a critique of the newly released final investigation report of the Ethiopian government of the March 10, 2019, crash of a Boeing 737 MAX.
Ethiopian Airlines flight ET302 came five months after Lion Air flight JT610, a MAX, crashed. Both accidents began when the Maneuvering Characteristics Augmentation System (MCAS) activated following a failure of the single Angle of Attack (AOA) sensor to which it was tied malfunctioned (JT610) or failed (ET302).
Boeing issued a notice to MAX operators after the Lion Air crash outlining proper procedures pilots should follow in case MCAS erroneously activated again. The Ethiopian government investigation placed the blame for the crash on Boeing. The NTSB’s critique concluded the pilots failed to follow Boeing recommendations and should be partly held responsible for the probable cause of the crash. Had they followed procedure, the NTSB concludes the pilots could have successfully flown through the emergency.
Bjorn’s Corner: 737 MAX ungrounding, ANAC’s and EASA’s decisions
By Bjorn Fehrm
November 27, 2020, ©. Leeham News: After the lifting on the grounding order by the FAA, ANAC (Brazils regulator) followed in the week, and EASA issued its plans for public comment.
What are the differences in the ungrounding conditions, and what are the reasons for any differences?
Figure 1. Circuit Breaker placement for the 737 NG and MAX. Source: Leeham Co. and Flightdeck737.be
Boeing 737 MAX changes beyond MCAS
By Bjorn Fehrm
November 24, 2020, ©. Leeham News: Last week, we went through the core MCAS changes the FAA demanded from Boeing to lift the grounding of the 737 MAX 8 and 9. As the investigation into the MAX crashes deepened, changes were added beyond the core MCAS related changes.
A single sensor failure, like the Angle of Attack failures for Lion Air JT610 and Ethiopian Airlines ET302, triggered a multitude of failure warnings. These warnings absorbed the crew’s concentration, invalidating FAA certification assumptions on crew reaction times for critical trim failures. As a result, the FAA required additional crew alert and procedure changes for the MAX.
Bjorn’s Corner: 737 MAX ungrounding, the technical background
By Bjorn Fehrm
November 20, 2020, ©. Leeham News: This week’s big news is the lifting of the grounding of Boeing’s 737 MAX.
I wrote about the changes made to the MAX Wednesday and why I believe it’s safe. Let’s use our Corner space to walk through what I wrote about, but with a more technical angle.
Figure 1. 737 MAX nacelles (right) compared with 737 NG nacelles (left). Source: Boeing and Leeham Co.
FAA recertifies Boeing 737 MAX
- Continuing coverage in next post
By Bjorn Fehrm
November 18, 2020, ©. Leeham News: The FAA has declared the Boeing 737 MAX 8 and 9 safe to fly after a 20 months grounding. On March 10, 2019, the Ethiopian Air ET302 crashed after Boeing’s pitch augmentation software MCAS triggered erroneously and caused the aircraft to crash. This accident followed a similar accident of Lion Air JT610 on October 29, 2018.
Ethiopia grounded the MAX on the day, China the day after, and the FAA on March 13. The 737 MAX has been grounded worldwide since the FAA grounding.
It has been a gruesome 20 months for Boeing, where it’s gone from denial of guilt to a full acceptance of responsibility and a complete change of attitude. With changes to the MAX verified by FAA, EASA, Transport Canada, and Brazil’s ANAC, it’s now ready to fly again.
We will cover the return to flight of the 737 MAX in several articles, the first dealing with the question: Is the 737 MAX safe to fly?
Below we go through what went wrong and why this chain of events will not happen again on an updated 737 MAX.
Why is the 737 MAX safe now when it wasn’t before?
Subscription Required
Now open to all readers.
By Bjorn Fehrm
Introduction
September 14, 2020, © Leeham News: The FAA and EASA Safety of Flight authorities have examined and test flown the changes Boeing has done to the 737 MAX to make it safe to fly again. Everything points to these authorities re-certifying the 737 MAX as safe to fly in the coming months.
In a Saturday article Dominic Gates of The Seattle Times quotes from a recent interview with me and an experienced 737 Captain, Mike Gerzanics, where we both say we consider the MAX safe to fly with the changes.
Here my reasons as an aeronautical engineer why I think so.
Summary
- The original design of a smoothing software for the 737 MAX flight control system was badly implemented.
- It’s not the changes to the 737 MAX base aircraft that makes it unsafe, such as larger engines, it was an unusually sloppy implementation of the smoothing software, called MCAS, that was flawed.
- MCAS is now properly implemented and tested. This returns the 737 to the safe aircraft it was before MCAS was implemented.
Boeing MAX crisis dominated 2019 Top stories
By Scott Hamilton
Dec. 30, 2019, © Leeham News: Boeing and the 737 MAX dominated the Top 10 Stories on Leeham News in 2019.
This should surprise no one.
The year-end late-breaking news that Boeing CEO Dennis Muilenburg had been fired by the Board of Directors should be in the Top 10 Stories of 2019.
But coming as it did on Dec. 23, the start of Christmas week, it failed to make it into LNA’s Top 10 list.
Readership, obviously, falls off dramatically over the Christmas holidays. The fall-off continues between Christmas and New Year’s evidenced by LNA’s own decision to take a holiday (except for breaking news).
The Ethiopian Airlines crash on March 10 grabbed three of the Top 10 stories and shared, with Lion Air 610 (the Oct. 29, 2018, crash) a fourth story.
Boeing photo.
Boeing’s pickle with the 737 NG pickle fork cracking was of the Top 10 stories.
An historical review that Boeing didn’t want to re-engine the 737, preferring instead a new airplane in 2011 when what became the MAX was launched, was in the Top 10.
An April 2018 story about a potential Blended Wing Body airplane from Boeing hit the Top 10 after an enthusiast site linked it to its forum.
Other MAX MCAS stories were in the Top 10. Finally, anticipated announcements by Mitsubishi for the Paris Air Show was the only non-Boeing story to be in the Top 10 reads for the year.
Airbus didn’t hit the Top 10 but did have a #11 story concerning a pitch-up issue on the A321.
The Boeing stories propelled record readership on LNA in 2019.
Here is the rundown.
FAA: No MAX certification until 2020; analysis forecast 15 more crashes if MCAS not fixed
Dec. 11, 2019, © Leeham News: A new round of Congressional Hearings about the Boeing 737 MAX got underway today.
FAA Administrator Stephen Dickson, testifying today before the US House Transportation Committee in a hearing about the Boeing 737 MAX.
Before the hearing began at the House Transportation Committee, FAA Administrator Steve Dickson appeared on CNBC today. Among his statements: recertification of the MAX will slip to 2020, confirming what had become apparent for some time.
“Like I said there are a number of processes, milestones, that have to be completed,” Dickson said in an interview on “Squawk Box.” “If you just do the math, it’s going to extend into 2020,” he told CNBC.
- Transcript of CNBC interview: CNBC Dickson transcript 121119
Pontifications: Congressional hearings on Boeing dominated by grandstanding–but damning documents revealed
By Scott Hamilton
- Senate hearing largely theater.
- House hearing has grandstanding, but substance, too.
- House reveals some damning documents.
- Muilenburg claims no knowledge of legal strategy, but top lawyer reports directly to him.
Nov. 4, 2019, © Leeham News: Last week’s Congressional hearings about the Boeing 737 MAX crisis was just as I expected: theatre, lots of grandstanding, little substance and testimony that elicited little in the way of new information.
The US Senate hearing was a perfect example of playing to the television by many Senators.
The House hearing certainly had its share, but in more lucid moments, some House members produced new documents that were especially damning to Boeing.
Boeing CEO Dennis Muilenburg and John Hamilton, VP and chief engineer, did no harm to Boeing, which was probably the prime objective. (Hamilton is no relation to me.)
Muilenburg did harm to himself, however, and some Members of Congress landed some damning blows.
Bjorn’s Corner: Analysing the Lion Air 737 MAX crash, Part 1.
By Bjorn Fehrm
November 1, 2019, ©. Leeham News: We start the series on analyzing the Lion Air 737 MAX crash by looking at what went wrong in the aircraft. It’s important to understand MCAS is not part of what went wrong. It worked as designed during all seven Lion Air flights we will analyze in this series.
It was a single sensor giving a faulty value that was wrong with these aircraft. How a single faulty sensor could get MCAS to doom the JT610 flight (called LNI610 in the report) is something we look into later in the series. Now we focus on why the sensor came to give a faulty value for five out of seven Lion Air flights and how these flights could be exposed to two different sensor faults.