Propeller Problems

The following is derived from maintenance facility submissions to the FAA’s Service Difficulty Reports database.

Editorial Staff

Saturday, May 04, 2024 at 08:00 AM ET

Verified

Key Takeaways:

Propeller malfunctions reported include oil leaks, excessive vibrations, and unintended feathering during shutdown.
Root causes identified were diverse, ranging from worn internal components (piston, vent system) and improper repairs to issues requiring dynamic balancing.
These incidents often necessitated significant maintenance actions such as prop removal for re-sealing or extensive repair, part replacement, or dynamic balancing to restore safe operation.

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Cessna R182 Skylane RG

Worn Actuating Piston

Propeller was leaking oil. Had our shop pull the propeller and send it off to be re-sealed. Prop shop discovered that the piston had worn out of spec. Scoring was found on the inside of the piston where it rides on the guide. Wear marks are 180 degrees apart on the front and back. Seems that the piston was cocked while moving on the guide rod. Part replaced and prop was re-sealed.

Part total time: 800.0 hours

Cessna 208B Grand Caravan

Excessive Vibration

During cruise flight, the aircraft experienced a vibration considered excessive. Propeller speed was reduced from normal cruise setting cleared the vibration for a short time. As flight continued, the vibration returned. Pilot declared an emergency and landed at destination/closest airport without incident. External visual inspection of engine and propeller and engine accessories failed to identify a problem. Propeller was dynamically balanced with 28.4 grams of weight used. A test flight was performed after the propeller was balanced with no vibration noted. No AD`s apply to this prop at this time.

Part total time: 8244.0 hours

Diamond DA42 Twin Star

Failed Vent System

At 697 hours since overhaul, oil began pouring out of the vent hole on the face of the prop hub. The propeller had to be removed and sent in for extensive disassembly and repair.

Part total time: 2146.0 hours

Piper J3 Cub

Improper Repair

Propeller in service since 2015/100 hours. Metal tipping replaced in December 2021. During initial climb after reinstallation, customer reported severe vibration; he cut power and made a successful power-off landing on a road close to the airport. No injuries or major damage. Minor portion of metal tipping and major portion of wooden blade missing on one side. Spinner skull cap also missing (was present during takeoff).

Part total time: 100.0 hours

Piper PA-44-180 Seminole

Feathering At Shutdown

Pilot reported that the right propeller was feathered when he went to do his walk around. An engine run was carried out with no defects found. When the engine was shut down the propeller would start to feather within 30 seconds and continue until it was fully feathered. The prop was replaced with an overhauled unit.

Part total time: 2043.0 hours