If N1 and/or TOT is the power limiting factor below 80 KIAS, which limits may be applied?

• A. N1 and/or TOT, below 80 KIAS
• B. N1 and/or N2, below 80 KIAS
• C. N2 and TOT, below 80 KIAS
• D. N1 and TOT below 90 KIAS

Answer: (A)

Power limiting at low airspeeds is governed by the engine’s internal limits, not rotor limits. When you’re operating below 80 KIAS, the engine can be restricted by either the gas generator speed (N1) or the turbine outlet temperature (TOT), and sometimes both. N1 controls how much fuel and air the gas generator can produce, setting the available power, while TOT protects the turbine from overheating. N2 is not used as the power-limit factor at this low-speed regime, and applying a limit tied to 90 KIAS isn’t relevant for below-80-KIAS operations. So the limits that may be applied in this regime are N1 and TOT below 80 KIAS.