Recognising engine issues in flight following a bird strike

by C.Gray 2023

Damage to the propeller

Propeller tip damage after a bird strike
If there is a sudden imbalance/shaking from the engine, and any RPM adjustment has little effect on the vibration, the most likely reason is propeller damage.


Solution: The engine may need to be stopped, to prevent further damage to the engine mounting integrity. You may be able to find an RPM where resonance is the least though, thereby retaining some power.



Engine induction air intake blockage

An engine sucks air in through a filtered inlet, called the induction intake. An engine induction intake blockage will probably cause an immediate step loss of power, and could lead to a gradual continuation of loss of power, until the engine is incapable of proper combustion. The resulting overly rich mixture in the cylinders may cause associated backfiring, and potentially a fuel smell in the cockpit at low speed as the unburnt fuel exits the exhaust pipe.

Remedy: Provide another induction air source: Alternate Air Source OPEN or Carburettor Heat ON. If the power is immediately restored the reason for failure is confirmed. Some ALT air sources are automatic, with a spring loaded intake door, and some are rotary sleeve valves (Diamond aircraft) that require pilot to actively select. 


Engine Cooling intake blockage

Any blockage in the engine cooling intakes will not directly affect engine power output. It will affect cooling, which could show up as rising CHT. If it is due to a bird strike there may be associated burning smell due to the feathers and carcass.

The air intake to the Oil cooler could also be blocked up at the same time if it is located in the cooling air intake area (e.g. DA40.) Some nacelle/cowl designs have a separate oil cooler air intake. A blockage of an oil cooler could cause a rise in oil temperature, and possibly a drop in the oil pressure.

Remedy: No remedy in flight. Land as soon as practicable to clear the blockage. 



Closing Summary

Learn al there is to know about your aircraft! In this case learn about the airflow and intakes on your aircraft. Understand the effect blockages of any part could have and how it it likely to show up. Such knowledge will arm you to make educated decisions in flight, and reduce hasty guesses.









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