“Prop strike.” These two words are guaranteed to make any pilot wince. A propeller strike is dangerous, not only because it damages the propeller but also because it can cause hidden damage that may lead to catastrophic engine failure.
While no one wants to experience a prop strike, the fact is, accidents happen. Knowing how prop strikes occur and what steps to take after an incident can help you avoid potentially dangerous and expensive situations.
You might think that a prop strike is simply when the propeller blades hit something. But there’s a little more to it. Each major engine manufacturer provides specific directives on what constitutes a propeller strike and what maintenance steps are required post-strike.
As an example, Lycoming defines a prop strike as:
Always refer to your manufacturer’s recommendations if you experience or suspect a prop strike.
Propeller strikes can happen to anyone. Sometimes they are preventable, but sometimes they aren’t. Here are some common scenarios when propeller strikes happen:
A propeller strike, no matter how “minor” the incident, should not be ignored. Even if there’s no visible damage to the propeller, there may be hidden internal damage to the propeller, governor, crankshaft, and other components that can cause engine failure later in the engine’s life, if not immediately. After a prop strike event, a complete propeller inspection is required. Depending on the damage revealed in the inspection, the propeller may need to be removed, disassembled, and overhauled by a certified propeller repair station. Never try to straighten bent propeller blades or tips yourself. It’s dangerous, not to mention illegal.
Most engine manufacturers also strongly recommend or require an engine tear-down inspection following any prop strike, sudden stoppage, or loss of propeller blade tip. You truly can’t find out if there’s interior engine damage until you open up the engine. Like most airplane maintenance decisions, it’s better to be safe than sorry. In a tear-down inspection, a skilled mechanic will remove and disassemble the engine to complete a detailed internal inspection of the reciprocating and rotating parts. From there, a complete engine overhaul may be necessary. As with all maintenance and repair concerns, refer to your propeller and engine manufacturer’s guidelines.
Lastly, be careful when purchasing a pre-owned airplane with a prop strike in its history. Be sure you understand what happened during the incident and how it was repaired. Having a pre-purchase inspection performed by a qualified mechanic can help reduce your personal and financial risk.
If you have technical questions about your Hartzell propeller, we’re happy to help. Get in touch with our technical team by emailing firstname.lastname@example.org.