FAA Ground School Practice Test

When an aircraft is in the area of two different time zones, how is the estimated time of arrival determined?

1. By calculating the time difference before the flight

2. By using local airport times only

3. By adjusting arrival time to account for wind speed

4. By adjusting for the time difference and flight duration accurately

The correct answer is: By adjusting for the time difference and flight duration accurately

The estimated time of arrival (ETA) is calculated by taking into account both the time zone difference and the flight duration. When an aircraft crosses into an area that spans different time zones, it is crucial to adjust the ETA accordingly to reflect the local time at the destination. This means considering how many hours ahead or behind the local time is in comparison to the departure point and then adding or subtracting this difference from the total flight duration. This approach ensures that you arrive at the correct local time. Simply calculating the time difference before the flight, using only local airport times, or adjusting for wind speed alone will not yield a correct and precise ETA because they do not fully encompass the relationship between the flight duration and the variances created by crossing time zones. Accurate flight planning requires a comprehensive understanding of both the duration of the flight and the effects of the time zone changes.