Returning the MAX to service

Discussion
Software upgrade

Boeing designed a software upgrade, restricting the number of times MCAS can activate, to one from unlimited, allowing pilot input override, restricting the travel of the horizontal stabilizer and linking the software to two Angle of Attack sensors instead of one.

The US Federal Aviation Administration is expected to receive the changes this week. FAA representatives already have been on board test flights, but more analysis is required.

While Boeing now is making AOA disagree instrumentation standard instead of optional equipment as part of the changes to MCAS, LNA understands that a warning light will become mandatory.

Regulatory approval

With the FAA being the last agency in the world to issue a grounding order for the airplane, faith in the agency—once considered the world’s gold standard for safety—has been shaken.

Officials of Europe’s safety agency, EASA, and Transport Canada previously said they want to do their own review instead of relying on the FAA’s determination to lift the grounding.

FAA officials said they no longer want to act alone to lift the grounding but want global consensus.

EASA’s absence from the Boeing briefing last Wednesday may or may not be significant and may or may not have been intended to send a message to Boeing.

Regardless, the optics don’t look good.

It’s not clear what, if anything more, EASA may depend to lift its grounding order but the process will certainly carry into April.

China’s plan to lift its grounding order is, as is often the case with Beijing, murky.

China’s airlines had more MAXes in service than any other country: 96. China is a supplier on the 737 and Boeing recently opened a 737 finishing center in China.

Boeing is continuing production at its full rate of 52 airplanes per month during the grounding. The grounding by the FAA doesn’t preclude ferry flights but it’s unclear whether China’s grounding order would permit Boeing to fly 737s into the airspace to the finishing center.

China has a history of using aircraft orders as political or business statements. More recently, China withheld plane-by-plane operating certificates for Airbus to make a business point. Will China do the same with Boeing?

Bernstein Research, in a March 28 note, doesn’t see the MAX returning to the skies until July. Air Canada previously said it’s removed the MAX from its schedules until July 1.

Narrowing in on the cause

While the investigations of the Lion Air and Ethiopian Airways crashes will take more than a year to determine all the causes, the recovery of the flight data recorders and cockpit voice recorders, along with control tower tapes and other evidence, already points to MCAS, the single AOA sensor to which MCAS was linked and questions over pilot training and actions.

In the case of Lion Air, questions also arose over a flight the previous day with the same airplane and a similar erratic flight from which the pilots recovered, and whether the airline’s maintenance department fixed the AOA sensor.

Broadly, the following points appear to be contributory factors to the two accidents:

  1. Bad MCAS design.
  2. Single point of failure—linking to one AOA instead of two.
  3. Failure to tell the airlines/pilots of the MCAS.
  4. Failure to have warning systems as standard equipment in cockpit.
  5. Possible poor maintenance at Lion Air.
  6. Possible poor communication at Lion Air between the crew on the preceding flight and subsequent crews.
  7. Pilot actions at Ethiopian.

There’s going to be enough blame to go around for everyone.

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