In calculating time en route, which factor is least likely to affect your calculation?

When calculating time en route, the factor that is least likely to affect your calculation is navigational aids. True airspeed, wind speed and direction, and departure and climb-out time all have a direct impact on the time it will take to complete a flight.

True airspeed is essential as it determines how fast the aircraft will travel through the air, which directly influences the time en route. Wind speed and direction can significantly alter the effective ground speed of the aircraft, either lengthening or shortening the time it takes to reach the destination depending on whether the wind is a headwind or tailwind.

Departure and climb-out time also affects the total time it takes to reach a destination, as it includes the time from takeoff until reaching cruising altitude and is an essential component of the overall flight time calculation.

In contrast, navigational aids are primarily tools used for guidance during the flight, such as GPS or VOR. While they help ensure that the aircraft is on course, they do not inherently change the basic time calculation for how long the flight will take, which is fundamentally based on the speed of the aircraft and the distance to be traveled. Therefore, their effect on the time en route calculation is indirect and not as significant as the other factors listed.