12 / 20

Given the following information, at what time will the PSR be reached?

Endurance: 6 hours
Leg track: 270°
TAS: 200 kt
Wind: 270°/20 kt
Departure time: 14:00

  • A
    17:18
  • B
    16:47
  • C
    16:58
  • D
    17:00

Refer to figure.
The Point of Safe Return (PSR) is the last point on a route at which it is possible to return to the departure airfield arriving back with the required fuel reserves still available in the tanks. If the pilot chooses to continue past the PSR, he is now committed to landing at your destination.

Time (to PSR) = E x H / 0 + H

  • Where, E = Safe endurance based on available fuel; H = Ground speed home; 0 = Ground speed out

Solving from Heading (HDG) & Ground Speed (GS), knowing WV, TAS and required track.

1. Set wind direction to 270º under the "TRUE HEADING" index at the top.
2. Set the center point on the True Airspeed (TAS) of 200 kt.
3. Mark the wind velocity 20 kt down from the centre point.
4. Initially, set the True Track under the "TRUE HEADING" index.

  • GS home: 090º
5. The groundspeed for this track is approximately 220 kt.
  • GS out: 270º

5. The groundspeed for this track is approximately 180 kt.


We can now apply the formulas:
Time (to PSR) = E x H / 0 + H
Time to PSR = 6 x 220 / 180 + 220 = 3 h 18 min

PSR will be reached at: Departure time + Time to PSR = 14:00 + 3:18 = 17:18

Your Notes (not visible to others)



This question has appeared on the real examination, you can find the related countries below.