With the on going grounding of 737 Max, if some airlines want to change their 737 Max to 737 NG what modification is needed? The main change would be the engine and control system. Any other change is needed in order for the plane to be re-certified for flight?

  • $\begingroup$ Probably they would have to do full certification flying program which is very expensive!!! And who wants NG instead of Max? If Max never flies probably the best option is to remove engines and scrap the rest. $\endgroup$
    – Andrius
    Oct 30, 2019 at 21:00
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    $\begingroup$ @Bianfable re-certify the MAX as much as you want. Most people will refuse to fly in one anyway. $\endgroup$
    – Quentin H
    Oct 31, 2019 at 11:15
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    $\begingroup$ @QuentinH I doubt that. With fixed MCAS logic there is no reason to assume the MAX is less safe than any other airliner. It might actually be safer because they are taking their time now to check everything very carefully. And passengers usually cannot really pick which aircraft they want to fly in anyway, they just care about cheap prices. $\endgroup$
    – Bianfable
    Oct 31, 2019 at 11:19
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    $\begingroup$ Nice question from aircraft design point of view. Retrofit to an older design is a challenge, that worth further discussion. $\endgroup$
    – JetSonic
    Nov 7, 2019 at 16:05
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    $\begingroup$ I'm curious if there is any way for Boeing to recover some costs from the hundreds of MAXes they have sitting around, in the event the MAX is never able to fly again. Would it be feasible for a manufacturer to have a conversion program for MAX -> NG? $\endgroup$
    – zymhan
    Dec 19, 2019 at 13:24

1 Answer 1


This page lists all the functional differences between the MAX series and the previous 737 variants. There are quite a bit of substantial changes like the reshaped tail cone and electronic bleed system. Not only are the engines different but the mounting pylon was changed to account for the new engines so you likely cant just "bolt on" the old engines. Even the cockpit has a different panel.


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