Critical-engine reasoning and directional control
Multi-engine aeroplane theory must distinguish the control problem from the performance problem. After a power loss, the aircraft can have sufficient directional-control authority but inadequate climb capability, or a different condition can challenge both. A minimum-control-speed marking is not a promise of positive climb or a complete emergency response. Use the actual aircraft flight manual and qualified practical instruction for flight operations.
Thrust, drag and moment arms
Asymmetric thrust creates a yawing moment that depends on thrust and its distance from the relevant reference. Drag from the inoperative side also affects the balance. Rudder effectiveness depends on airflow, geometry and available control authority. Blade rotation and loading can change the effective thrust line, so declare the viewing convention and propeller directions before applying a left-engine memory rule.
For the stated conventional twin with clockwise propellers viewed from behind, P-factor shifts the effective thrust toward the descending blade under the relevant condition. The operating right engine can then have a longer effective thrust arm when the left engine fails. Counter-rotating arrangements change the comparison; a particular model's configuration must be established rather than inferred from the number of engines.
Vmc is condition-dependent
Vmc relates to directional control with the specified engine-out and certification conditions. It is not a stall speed and does not automatically equal the speed required for best single-engine climb. Weight, center of gravity, bank, available power, configuration and the failed propeller's drag can affect the control balance. A higher density altitude does not universally lower Vmc when the operating engine can maintain power through turbocharging or another control system.
A small bank in the appropriate direction can help the defined control balance, while center-of-gravity position changes the effective restoring moment. These relationships do not authorize improvising a bank angle or ball position. The actual aircraft data and training govern the approved technique and limits.
Identification and verification
A foot-pressure mnemonic can be an initial clue under its assumptions, but is not proof of a failed engine. Cross-check the relevant indications and follow the actual identify-and-verify procedure before any irreversible action. A mistaken shutdown of the operating engine can remove the remaining thrust. This chapter gives no universal throttle, feathering, gear or flap sequence.
Study the difference between an unstalled loss of directional control, a stall and a spin. Training demonstrations require the approved conditions and safeguards; the practice bank is not an instruction to conduct one. Written recognition cannot establish practical proficiency or a safe engine-out flight path.