Piper PA34 N16499 accident near Hollywood, Florida

Probable cause

Maintenance personnel’s failure to comply with an airworthiness directive for the propeller, which resulted in a propeller hub failure due to fatigue.

NTSB analysis

During an instructional flight in a multiengine airplane, the pilot receiving instruction had just completed a right turn at an altitude of 3,300 ft mean sea level when the flight instructor heard a loud noise and saw something separate from the right engine. The flight instructor took the controls but was unable to maintain altitude with one engine operating and performed a forced landing into a swamp. Examination of the wreckage revealed that the right engine had separated from its mounts, one propeller blade was missing, and the right propeller hub was fractured. Metallurgical examination of the propeller hub revealed a fatigue fracture along a grease-fitting hole. An airworthiness directive had been issued about 8 years before the accident that required initial (within 50 flight hours) and repetitive (every 100 flight hours) eddy current inspection of the area around the lubrication holes of the propeller hub blade sockets. The right propeller had been overhauled about 14 months before the accident and had accrued about 440 hours at the time of the accident. The airplane's most recent 100-hour inspection (which included inspection of both propellers) occurred about 3 months before the accident. Review of maintenance records did not reveal any documentation that the airworthiness directive was complied with on the overhauled right propeller hub.

Text from the NTSB. Open the NTSB docket for ERA16LA295 for the full record.