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Following a propeller strike with damage to the propeller it is imperative that checks are carried out to ensure that engine internal component damage has not occurred. If the engine is run after a propeller strike without these checks having been carried out, further catastrophic damage can destroy the engine, sometimes several hours later.

 

The following checks are made during a shock load check:

 

• Propeller shaft, hub and gears tested for cracks and run out
• Gearbox casing in testing for cracks around the main bearing
• Propeller shaft bearings are replaced
• Crankshaft PTO end journal is tested for run out
• Crankshaft magneto flywheel end journal is tested for run out
• Crankshaft phasing checks are carried out
• Woodruff key is checked for distortion and cracks
• Crankshaft woodruff keyway is checked for cracks
• Magneto flywheel is checked for cracks around the hub
• Slipper clutch is checked for correct slipping torque

 

When a slipper clutch is fitted to the engine the crankshaft and flywheel are protected. However, damage may still occur within the gearbox and the first 5 checks in the list are necessary.