Originally Posted by
Hotel Kilo
The 8 & 9 are basically re-engined 737 8/9.
The MAX 7 is different than the 73-7, so treated as a "new" airframe. The MAX 10 is the Uber stretched 73 and is considered a "new" airframe. Thus both the 7&10 require certification.
That's the 2 minute or less explanation. It's a bit more involved than this but that's about all one needs to now without getting really wonky.
in addition to this, the -8 and -9 were already certified when the max debacle unfolded in 2019. My understanding is the engine cowl issue holding up certification of the -7 and -10 was allowed to go unresolved for the -8 and -9 because when they were certified the FAA was not seriously regulating Boeing. Now that they are actually overseeing Boeing, they won’t certify the other 2 with the same issue.