Boeing is making progress on a redesign of the 737 MAX-7 engine nacelle, to permit its FAA certification. But more delays seem inevitable.
The smallest member of the 737 MAX family is also the one with the smallest number of orders. Unless something changes radically, the predominant user, once it enters service, will be Southwest Airlines.
Work on the certification of Boeing’s 737 MAX-7 was underway when the two 737 MAX-8 crashes, in 2018 and 2019, caused the type’s grounding. Testing and certification work on the aircraft essentially came to a halt, as Boeing and the FAA radically changed the ways they work with each other.
Engine Anti-Ice Issue
More recently, we have seen that the certification of both the 737 MAX-7 and MAX-10 has been hit by a new issue, involving the engine nacelles. If flight crews use the engine anti-ice system under certain specific conditions (altitude and air temperature), the composite structure of the nacelle could suffer a structural failure.
This issue also affects the 737 MAX types already in service. But for now, Boeing has temporarily mitigated the issue by implementing a procedure whereby pilots switch off the engine anti-ice when it isn’t necessary. The FAA has approved this process – but has been reluctant to complete the certification of the MAX-7, under the same conditions.
The backlash after the 737 MAX-9 door plug blowout in January meant that Boeing abandoned any hope of putting the MAX-7 in service without an engine nacelle redesign. The latest news is that Boeing has now concluded its design work on the new nacelle, and plans to flight test it later this year.
737 MAX-7 Certification – Still Plenty of Waiting Left
But even if testing is successful, the 737 MAX-7 likely won’t get certified before mid-2025. Southwest has previously said that it is prepared to wait for the MAX-7 to come, as it has little choice on the matter.
The airline needs the smaller type, to match its current network. However, it will need several months after its first 737 MAX-7 delivery before it can put the variant into service. So, the first Southwest 737 MAX-7 could carry passengers for the first time as late as early 2026.
Boeing also needs this new nacelle design for the 737 MAX-10, and will later apply it to the rest of the 737 MAX family. Right now, Boeing reportedly has 35 MAX-7 and MAX-10s in its inventory, awaiting certification.
The larger variant has a more diverse list of customer airlines. But unlike the MAX-7, whose certification now depends mainly on the nacelle, there is still more work to do before the MAX-10 can enter service.
For more on the issue and details on Boeing’s engine nacelle fix, check out this article on The Air Current
