B-737 Max and the recent NTSB response

by | 2023-05-06

I just recently came across the January 13th 2023 NTSB response to the Ethiopian Airlines flight 302 Boeing 737 Max accident of March 10th 2019. Wow… Not so much as a surprise but rather as a very unusual procedure in the industry.

First, a bit of background to put the event in context. There were two fatal B-737 Max accidents. The first in October 2018, Lion Air (commented on this blog)and then in March 2019, Ethiopian Airlines flight 302.

Both accidents were heavily covered by the media from all sources. The loss of human life was hearth breaking. Passengers put so much confidence into the airline transportation system. The airline corporations, the regulators, manufacturers and ultimately the pilots at the flight controls all share in building this confidence.

By ICAO standards, an aircraft accident investigation is conducted by the authority of the country where the occurrence occured. Further, the authority’s agency for the country where the manufacturer is based will be required to produce a report. A country may also require the help from other authorities in order to assist should resources be limited.

The March 2019 accident investigation was under the respnsibility of the Aircraft Accident Investigation Bureau of Ethiopia (EAIB) and the American National Transportation Safety Board (NTSB).

The EAIB produced the final report on December 23rd 2022. On January 13th 2023 the NTSB produced a 7 pages very precise response letter. it can be clearly read as a clarification, an opposition to major contributing factors. This was in my view, a major aspect in the 737 Max saga.

From the start, let’s be perfectly clear. Boeing and the FAA were at fault in the 737 Max manufacturing and certificating fiasco. They were part of the major contributing factors for those fatal accidents.

This is where the NTSB January letter comes into context. Bear with me for a minute.

The NTSB was created in 1967. it was an investigative arm of the newly created American Department of Transportation (DOT). In 1974, the NTSB was seperated by the elected government of the time from all governmental affiliation. This was to provide the NTSB with an apolitical, non biased investigative capacity. The NTSB calls things as they see them. The EAIB does not enjoy such independence.

It is an ICAO protocol to have the manufacturer’s country of origin investigation authority to assist, produce and comment the concerned domestic authority’s work and report.

The EIAB produced 3 accident report drafts which were all commented by the NTSB. Yet, the NTSB comments largely based on human performance were not included in any of those drafts. The EAIB blamed solely Boeing. This explains the very unusual letter of response from the NTSB.

First and foremost and I repeat myself, it is abundantly clear the Boeing and the FAA failed in their business case for the B-737 Max development.

What personally got my attention and not mentioned in the EAIB report were the human factors of the accident itself. Following the Lion Air accident and 4 months prior the Ethiopian Airlines, an FAA Emergency Airworthiness Directive was issued. As we know in the industry, when an AD is issued every one pays very focused attention. This AD required all B-737 Max operators to train their crew to the uncommanded (runaway) pitch trim condition. Apparently Ethiopian Airlines crew were not trained accordingly. The AD states to use the electric manual pitch trim to stop the runaway situation thus disconnecting the infamous MCAS then reduce power to 80%, pitch the aircraft up to reduce airspeed and finally select the trim cut-out switches to off. Those switches are readily accessible just right of the thrust levers position on the pedestal.

Did the flight crew accomplish any of the required procedure? Did the flight crew accomplish only partially the required procedure? regardless, it is still quite surprising to observe colleagues flying nose down in close ground proximity at over 400 knots and full power.

It is worth to mention that the MCAS system is not activated under the following conditions:

  • When flaps are extended
  • When manual electric pitch trim is operated
  • When pitch trim cut-off switches are set to off
  • When the auto-pilot is engaged

Further investigation revealed the failure of the left angle of attack probe into the take-off. The accident investigation revealed that a foreign object had thorn off the left AOA probe rendering the MCAS faulty. The final EAIB report did not include a laboratory reconstruction of the “incident”, provided by the probe manufacturer. They EAIB, unlike all stake holders, chose not to assist to the lab demonstration. The likelihood of a bird strike was predominant. The MCAS was not activated until 44 seconds after the take-off roll when the flaps were selected up.

As a pilot, sitting in front of my computer screen typing this article, I find it unbelievably easy under no duress to comment on the horrible fate in which the flight crew and their passengers were submitted. What is breathtaking is the willful disregard to science, facts and human performance.

Sometimes independent investigating agencies may not be perfect in their actions and recommendations. Processes exist to correct the rare imperfections. The ultimate goal is to avoid future accidents to occur. Choosing to ignore observations of facts such as this case is inexplicable and certainly warranted the NTSB’s letter of comment in trail of the EAIB final and limited report.

What we can take a very important lesson from this very unusual case. Human factors coming from all sectors of our industry contribute to safety. Indeed the pilots are the last chance to protect our passengers from tragic accidents. Science based training is the key to success in our quest for excellence. Ignore science and facts at your own risk.

Subscribe to Blog via Email

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Leave a Reply