What is NOT considered a multi-engine performance factor during flight planning?

The type of engine used in a multi-engine aircraft is not considered a performance factor during flight planning. Performance factors typically involve parameters that directly affect the aircraft's capabilities during flight, such as weather, weight, and balance.

Weather is a critical factor that can impact aircraft performance significantly, influencing climb rates, fuel consumption, and overall aircraft handling. Weight directly affects the aircraft's load capacity, performance in climb and cruise phases, and landing requirements. Balance is essential for maintaining the aircraft's center of gravity within limits, which affects stability and control during all phases of flight.

While engine type can influence aspects like fuel efficiency and horsepower, it is not categorized as a direct performance factor in the same way as the operational conditions that are considered in the other factors listed. In contrast, weight and balance are immediate concerns that pilots must calculate and manage to ensure safe and efficient operation of the aircraft.