A United Airlines flight that took off from San Francisco International Airport Friday morning landed in Oregon with a missing external panel, according to officials.
United says the missing panel wasn’t discovered until the plane landed safely in Medford and that pilots had no idea during the flight that something had happened.
That is not how it works for aircraft.
At least in general aviation, there is a maximum number of hours for certain parts that need to be overhauled. The engine installed onto a given aircraft may be designed by Rolls Royce or it may be designed by GE or it may be designed by Pratt and Whitney. Boeing doesn’t have expertise in it all.
Furthermore, each aircraft must maintain an airworthiness certificate. This is one of the ways the FAA can ground planes. For example, it can ground all planes of a given type until required maintenance is performed on a faulty part. Unfortunately, I’m not sure how the airworthiness certificate is determined for Boeing aircraft. I think the FAA has historically given great latitude to Boeing to certify their own aircraft.
HOWEVER, the A&P mechanic (airframe and powerplant) is responsible for maintenance. This license requires examination from the FAA. Some FBOs can maintain A&P, but usually the airline maintains its own aircraft (hence why either southwest or american has such a bad reputation).
The 737-800 has been in service for quite a while and its a proven platform. The only reason the 737-MAX is having issues is because they wanted to take the proven 737 platform and add a stupid design design to complete with the A320. If there really IS such a big issue with their manual, the FAA will step in and issue a directive. They have not done so for the 737-800. This is united’s issue.
Here you can search for the airworthiness directives for the 737-800: https://drs.faa.gov/search
One in 2001 and one in 2007.