The news never stops coming about Boeing 737s, although that's not surprising because there are more of them than any other commercial airliner. This week has brought encouraging news about the grounded 737 Max, and new, but temporary, worries for older models.
The issue for older 737s involves failure of an air check valve that can cause engine failure if it has corroded parts. After a series of engine failures, including one dual-engine failure, the FAA ordered inspections for over 2000 737s that had been in long-term storage for months. It appears that long periods of non-use may allow corrosion to get a foothold. The valves must be checked and if necessary replaced before the planes can fly as they come out of storage.
The 737 Max update is on the positive side; since the completion of post-modification test flights, airlines have begun anticipating its return to service; Southwest is said to hope to see it in service before the end of the year. However, there are numbers of steps remaining before it can be recertified, including FAA decisions on how much pilot retraining will be required.