How Airlines Are Able To Fly The Boeing 737 MAX During Its Grounding

Airlines are moving their grounded Boeing 737 MAX aircraft around the world, to escape harsh winter conditions, perform maintenance and move them into long term storage. However, many have asked how an airline can conceivably even be allowed to fly a ‘grounded’ plane, let alone one that has a critical flaw preventing airworthiness.

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The Boeing 737 MAX won’t return to service until next year. Photo: Boeing

To answer this question we need to look at the Boeing 737 MAX and why airlines are trying to move them despite the ban.

What is the story so far?

The Boeing 737 MAX aircraft is the fourth generation of the Boeing 737 design, arguably the most successful aircraft production line ever built (arguably as the rival Airbus A320 line is catching up fast). Each new generation of the Boeing 737 has added improvements to the original design, often bigger engines.

For the fourth-generation design, Boeing added such big and powerful engines that it slightly modified the aerodynamics of the aircraft. Specifically, the large engines had to be mounted closer to the rear, which increased the risk of pushing the nose too far up. As this would mean that pilots would need to be retrained (a very expensive cost for airlines and might prevent them from considering this new aircraft), Boeing decided to correct the upward push with a little nudge from an autopilot system, MCAS.

The flaw was that the MCAS took information from a single sensor, and in two cases where the sensor was broken, the system was inputted with false information. This resulted in two aircraft crashing (as the MCAS kept pushing the nose down) and killing over 300 passengers, pilots and crew.

Around the world, the Boeing 737 MAX series was grounded until Boeing was able to fix the flaw with the aircraft and provide training for airline pilots. This process is still underway and it is unlikely that the 737 MAX will see passenger flights until next year.

Boeing 737 MAX grounding 2020
Boeing’s timeline could be in jeopardy if other regulators decided to conduct their own safety checks. Photo: Boeing

Why do airlines want to move the 737 MAX aircraft?

As the northern hemisphere darkens and snow appears on the horizon, airlines are faced with a bit of a puzzle with the 737 MAX aircraft. As the planes were grounded were they stood, many were trapped across the country, or even in other countries (Fiji Airways had one MAX still in Australia when the order came through) far from their airline’s hubs.

Thus we can summarise below several reasons why the Boeing 737 MAX needs to be flown despite being grounded.

  • The aircraft is in an airport that is charging high fees, or trapped with some other financial circumstance. E.g. You can’t afford to store a jet long term at London Heathrow for example.
  • The aircraft is located in a region beset by storms, high humidity or other weather effects. It will become damaged and cost more to repair.
  • The aircraft needs to be moved from storage to a maintenance facility to prepare to be put back into active service, something that American Airlines is currently doing.
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Airlines want to ensure that the weather or humidity does not damage their MAX aircraft during this grounding period. Photo: Boeing

How do they move the aircraft?

With these important reasons, it seems airlines have managed to get permission from aviation authorities to move these aircraft… with some catches.

The first is that a specially trained pilot needs to be onboard. The pilot has been briefed about the MCAS system and trained in a flight simulator on how to correct it. Likely this pilot is accompanied by a Boeing official to ensure that the problem does not occur.

The aircraft is also flown slowly with flaps deployed, as this prevents the MCAS system from activating.

Flight paths are preplanned and authorized by the respective country aviation departments. For Silk Air’s plans to move Boeing 737 MAX aircraft to Alice Springs in Australia, not only do they need permission from Australian authorities but also from Singapore and Indonesia. These flight plans include flying away from urban centers and ensuring that the aircraft is carefully monitored.

Lastly, these aircraft are moved one at a time, with no passengers on board and around existing traffic. What do you think of the plan to move 737 MAXs, should they be allowed? Let us know in the comments.