Besides RPM, EGT, and compressor inlet temperature, what additional factor must be known to set the fuel flow in flight?

To determine the correct additional factor needed to set fuel flow during flight, it's important to consider how turbine engines operate. Fuel flow is closely related to the air entering the engine, which is influenced by both the compressor inlet pressure and airspeed.

Compressor inlet pressure affects the density of the air, which, combined with the airspeed (associated with the position of the power lever), impacts the combustion process. A higher inlet pressure or increased airspeed generally means more air is available for combustion, and, consequently, more fuel will need to be supplied to maintain the appropriate mixture for optimal performance.

Altitude and outside air temperature are relevant factors but, in the context of turbine engine performance, they are indirectly accounted for when considering compressor inlet pressure and the power lever position. Fuel viscosity does not play a role in this specific scenario.

Thus, understanding how compressor inlet pressure and airspeed work together helps establish the necessary fuel flow, which is vital for maintaining engine efficiency and performance during flight.