Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
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- How good is the C929? April 14, 2025
Ethiopia issues preliminary report of ET302 accident
April 4, 2019: Ethiopian aviation crash investigators today issued the preliminary report into the Ethiopian Airlines ET302 crash.
The report may be downloaded here: Preliminary Report B737-8 MAX (ET-AVJ).
LNA will have a report on the finding today or tomorrow.
ET302 used the Cut-Out switches to stop MCAS
By Bjorn Fehrm
Note: The article offered a Video as an example of the effects of not trimming to neutral before hitting Cut-Off. After reviewing the effects of the video in the context of the article, MentourPilot decided we should leave the text but not include the video any longer. MentourPilot’s YouTube channel is an independent initiative to offer the public correct and positive information of all the work which is behind their safe travel in the skies. In the sensitive situation of an ongoing investigation of the crash of ET302, where not all facts are on the table, he concluded after discussing the impression the video left with a colleague, it was not in line with his intent of setting up the channel. In the haste of the change we took this as his company not wanting the video aired, it was not. As facts in the ET302 case comes forward we will discuss with MentourPilot if this situation changes.
April 03, 2019, © Leeham News: The crew of Ethiopian Airlines ET302, which crashed with 157 people on board, used the prescribed Stabilator Trim Cut-Out switches to stop MCAS, according to an article by Wall Street Journal today. Yet still, they crashed. We’ve had the information this could indeed be the case for several days, but we didn’t want to speculate in such a sensitive matter.
The Wall Street article cites information coming from the investigation. By it, we can now reveal how it’s possible the aircraft can crash despite using the Cut-Out switches. To verify, we ran it all in a simulator together with MentourPilot Youtube channel over the last days.
Figure 1. ET302 ground speed as long as FlightRadar24 could follow the flight. Source: FR24.
Returning the MAX to service
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Introduction
April 1, 2019, © Leeham News: Returning the Boeing 737 MAX to services following its grounding should reasonably be a straight-forward affair, if past groundings were examples.
But, to mix a metaphor, there are plenty of unchartered waters with this grounding that stand ready to complicate matters.
Bloomberg reported Saturday that Europe’s FAA equivalent, EASA, skipped last week’s Boeing meeting of 200 pilots and regulators.
Summary:
- US FAA is no longer the leader or gold standard.
- EASA, Transport Canada want their own reviews.
- China, the first to ground the MAX, also suspended plane-by-plane certification.
Pontifications: I don’t know what to make of this
By Scott Hamilton
April 1, 2019, © Leeham News: One can’t help but think, a lot, about the two Boeing 737 MAX crashes and the facts that Boeing created the system, linked it to one sensor, not two, didn’t tell the airlines pilots about it, didn’t include it in pilot manuals, didn’t have a safety alert system as standard equipment, initially blamed the Lion Air pilots and reportedly lobbied Donald Trump not to ground the airplanes.
But my thoughts haven’t stopped here.
MCAS upgrade requires half-hour of pilot training
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Introduction
March 28, 2019, © Leeham News: Boeing 737 MAX pilots learning about the revised software upgrade to the Maneuvering Characteristics Augmentation System (MCAS) will need a half hour of computer-based training (CBT), the company told the media yesterday in a briefing.
Pilots of the 737 NG who have not yet made the transition to the MAX also have to be trained on the MCAS now. Boeing did not specify if this will take longer than those already trained on the MAX.
- Related article: Boeing presents MCAS software fix details
Summary
- No estimate to MAX return to service.
- Waiting for investigations of the crashes.
- More information for pilots.
Pontifications: Fluid, dynamic events upend MAX story
Special Edition
By Scott Hamilton
March 20, 2019, © Leeham Co: I’ve been covering or employed in commercial aviation since 1979. I’m an aviation historian buff.
I’ve read all about the groundings of the Douglas DC-6, Lockheed Constellation, Martin 202 and de Havilland Comet. I read about how the Federal Aviation Administration didn’t ground the Lockheed Electra, choosing operating restrictions instead.
I lived through the grounding of the McDonnell Douglas DC-10 and Boeing 787. As a reporter, I walked through the debris of the American Airlines DC-10 crash that led to the grounding. I went to the crash scene of the Delta Air Lines Boeing 727 at D/FW Airport and I’ve covered many, many crashes through reporting and as a commentator.
I’ve never seen anything evolve in air accidents as has evolved in the Boeing 737 MAX investigations.
Impact to Boeing for MAX grounding assessed
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Introduction
March 19, 2019, © Leeham News: The impact of the grounding of the 737 MAX to Boeing will hurt, but the effect likely will be short term.
The most recent grounding of an airliner was the 2013 grounding of the 787. This cost Boeing an estimated $500m over the course of the three month
grounding. A hardware fix had to be designed to contain battery fires. Installation in the field for 50 aircraft was required. Compensation to operators was necessary.
There are more than 370 MAXes grounded. Norwegian Airlines and Spice Jet already publicly said they will demand compensation. Deliveries are suspended.
This grounding should be much shorter than was the 787.
Summary
- MAX fix was already in the works.
- Some say US government shutdown delayed software fix at least five weeks.
- Implementing software upgrade will be quick.
- Grounding estimated by LNA to be six weeks max.
- MAX grounding cost estimated $550m over several years.
- Short term revenue shift $11bn to later in the year.
Pontifications: 737 MAX events remind of Lockheed Electra story
By Scott Hamilton
March 18, 2019, © Leeham News: There’s a saying that history repeats itself.
When it comes to the crisis of the Boeing 737 MAX, I’m reminded of the crisis Lockheed faced in 1959-1960 when the Electra propjet crashed in September and the following March, killing all aboard both airplanes.
The Electra entered service Jan. 12, 1959, with Eastern Airlines. It was considered a pilot’s airplane. Coming off decades of piston engine aircraft and early in the jet age, the Electra was the only airplane that was over-powered, piston or jet. Timing, however, was poor and crashes soon overtook the euphoria.
Read more
Bjorn’s Corner: The Ethiopian Airline’s Flight 302 crash
By Bjorn Fehrm
March 15, 2019, ©. Leeham News: With the crash in the weekend of Ethiopian Airlines Flight 302 we take a break from the Yaw and Roll stability discussions to look at what happened Sunday.
The 737 MAX 8 with 157 persons onboard crashed six minutes after takeoff. Here is what we know.
Commentary: Boeing’s Tylenol moment and the need for radical transparency
By Judson Rollins
March 13, 2019, © Leeham News: The traveling public’s faith in Boeing – and that of regulators in dozens of countries – has clearly taken a beating.
The 737 MAX has now been grounded or banned in nearly every jurisdiction in which it was operating just a few days ago.
Sunday’s tragic accident in Ethiopia bears an uncanny resemblance to the circumstances of the October crash of Lion Air 610, a fact which Boeing has tried 
to downplay by arguing that both accidents are still under investigation. The earlier accident is widely believed to have been caused by repeated nose-down trim responses driven by the MAX’s Maneuvering Characteristics Augmentation System (MCAS), which in turn may have been influenced by inputs from a faulty angle-of-attack (AOA) sensor.