The good news is that aluminum propellers are overdesigned and overbuilt so they operate safely for years. The bad news is that aluminum propellers are overdesigned and overbuilt so they operate safely for years. While each has a published TBO, for some reason aircraft owners who wouldn’t dream of running an engine past TBO will utterly ignore that number for a propeller.
Again, it’s a good news/bad news situation. The good news is that propellers don’t often break in flight—the risk is about the same as being involved in a midair collision—although, when they do, it’s usually catastrophic and means a crash of some magnitude, and aircraft owners spend lots of money on traffic alerting systems. . . The bad news is that the complacency brought on by the reliability of metal propellers often means that owners eventually spend more money on them than if they’d done a little preventive maintenance.