Propeller Engine Failure

081-07-02Pablo Asensio Martínez2026-04-011 min

Windmilling

When an engine fails, the airflow drives the propeller (it acts like a turbine).

  • Drag: Creates massive drag because the propeller is taking energy from the airflow to spin the dead engine.
  • Effect: Severe yaw towards the dead engine and reduced performance.

Feathering

Rotating the blades to a high pitch angle (~90°) so the leading edge faces the airflow.

  • Purpose: Stops rotation and minimizes drag. Essential for multi-engine safety.

Asymmetric Thrust (Multi-Engine)

Failure of one engine creates a yawing moment ($Thrust \times Distance\ from\ CG$) towards the dead engine.

  • Critical Engine: The engine whose failure results in the most adverse effects on handling and performance (usually the left engine on clockwise props due to P-factor).
  • Vmca (Minimum Control Speed Air): The lowest speed at which directional control can be maintained with the critical engine failed.
Written and reviewed by

Pablo Asensio · 2026-04-01

Aeronautical engineer. Passed the thirteen EASA ATPL(A) theoretical knowledge exams studying from these very notes. Writes and reviews each topic against the Part-FCL Learning Objectives.

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