Old helicopters must get their main rotor shafts checked for cracks

US aviation regulators want to make sure certain older helicopters are safe to fly. They propose requiring inspections of a specific part, the main rotor transmission drive shaft, for cracks.

This is a routine safety update for a specific model of helicopter that has been in service for decades. It means operators of these older aircraft will have to perform new maintenance checks to keep them flying. The goal is to prevent mechanical failures that could lead to accidents.