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Refer to figure.
A GPS system on board the aircraft uses True Airspeed (TAS) to calculate the leg duration. Based on the flight log provided, what total travel time to the destination will the GPS display?

  • A

    The total travel time will be equal to 1 hour 32 minutes as the TAS is equivalent to no wind.

  • B

    The total travel time will be earlier than 1 hour 32 minutes.

  • C

    The total travel time will be more than 1 hour 32 minutes, although the groundspeed is higher.

  • D

    The total travel time cannot be estimated.

Refer to figure.
Note: This question has been created based on incomplete feedback. More details are required, especially regarding the answers.


The following information can be extracted from the flight log:

  • Total time: 1 hr 32 min (based on the groundspeed)
  • True Airspeed (TOC → LIBR): Between 130 kt and 133 kt
  • Groundspeed (TOC → LIBR): Between 134 kt and 140 kt

Excluding the LIPB → TOC leg, the true airspeed remains consistently lower than the groundspeed, indicating a tailwind component for most of the flight. If the GPS calculates the total travel time using TAS instead of GS, the estimated total travel time would be more than 1 hour 32 minutes, as the aircraft would take longer to cover the distance.


"The total travel time will be more than 1 hour 32 minutes, although the groundspeed is higher." → CORRECT. As explained above.

“The total travel time would be equal to 1 hour 32 minutes as the TAS is equivalent to no wind.” → INCORRECT. The travel time can be exactly 1 hour 32 minutes if there is no headwind or tailwind component, meaning the groundspeed equals the true airspeed. However, true airspeed is the speed of the aircraft relative to the air mass through which it is flying, and it exists regardless of whether wind is present or not.

“The total travel time will be earlier than 1 hour 32 minutes.” → INCORRECT. If the GPS calculates the travel time using true airspeed, the duration will be longer because the tailwind component is not taken into account. In reality, the tailwind increases the groundspeed, allowing the aircraft to cover the distance in a shorter time.

“The total travel time cannot be estimated” → INCORRECT. Since the true airspeed for each leg is provided in the flight log, the travel time can be estimated based on this speed.

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