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Given the following information, calculate the distance from the Equal Time Point (ETP) to position B:

Distance from A to B: 360 NM
Wind component from A to B: -15 kt
Wind component from B to A: +15 kt
TAS: 180 kt

  • A
    170 NM
  • B
    195 NM
  • C
    165 NM
  • D
    180 NM

The Point of Equal Time (PET) allows a pilot to decide which is the quickest landing area to get to and is the position of a point on a track, where it is as quick to go on, as it is to turn back. The PET can be also called Equal Time Point (ETP) or Critical Point (CP).

The formula to calculate the position of the PET is:

  • Distance to PET = (D x H) / (O + H)

Where:

  • D: Sector Distance
  • O: Groundspeed Out
  • H: Groundspeed Home

1. The Groundspeed Out (O) is: TAS - 15 kt = 165 kt.

2. The Groundspeed Home (H) is: TAS + 15 kt = 195 kt.

3. Thus, the distance from A to PET is: (360 NM x 195 kt) / (165 kt + 195 kt) = 195 NM.

But, the question asks for the distance from PET to B, i.e. what is the remaining distance after passing the PET.

4. Therefore, the distance from PET to B is: Distance A to B - Distance to PET = 360 NM - 195 NM = 165 NM.

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