FAA Private Pilot Airplane (PAR)Navigation and Flight PlanningEasy
A pilot is planning a VFR cross-country flight. The true airspeed is 100 knots, and the planned ground speed is 90 knots. The total distance to the destination is 180 nautical miles. How long will the flight take?
- A1 hour 30 minutes
- B1 hour 48 minutes
- C2 hours 12 minutes
- D2 hours 0 minutes
Show answer & explanationAnswer & explanation
Correct answer: D. 2 hours 0 minutes
Time = Distance / Ground Speed. Given Distance = 180 NM and Ground Speed = 90 knots. Time = 180 NM / 90 knots = 2 hours. True airspeed is irrelevant for calculating flight time if ground speed is known.
Why the other options are wrong
- A. Calculated with an incorrect ground speed or distance.
- B. Calculated with an incorrect ground speed or distance.
- C. Calculated with an incorrect ground speed or distance.
Time-Speed-Distance Calculation
A fundamental navigation calculation used to determine the time required for a flight, the speed needed to cover a distance in a given time, or the distance covered in a given time.
- Time = Distance / Speed
- Distance = Speed x Time
- Speed = Distance / Time
- Ground speed is used for flight time calculations, not true airspeed.
Memory trick: Distance Over Speed Gives Time