What is the true airspeed (TAS) the flight is filed at?

The true airspeed (TAS) of a flight is a critical parameter that reflects the actual speed of the aircraft relative to the surrounding air. It is essential for performance calculations, navigation, and efficiency relevant to a specific flight plan.

In this case, the choice indicating 421 knots as the filed TAS is accurate due to the fact that typical commercial jet operations often plan for higher TAS to optimize fuel efficiency while maintaining the necessary distance and time management during flight. A TAS of 421 knots suggests that the aircraft is operating in a range that balances optimal cruise speed with the expected altitude and wind conditions, aligning with standard operational parameters found in flight operations manuals.

TAS is influenced by a variety of factors, including altitude, temperature, and air density. The 421 knots figure likely conforms to the expected operational speeds for flight segments within the airline’s established policies or within the parameters set by air traffic control, thus enhancing safety and conformity during flight operations.