Example
| TAS: | 110kts | Variation: | 12°E |
| Wind: | 320/10 (true) | Distance: | 100nm |
| TRK: | 350° (true) |
Before we start, we need to convert all bearings from true to magnetic.
When variation is East, subtract from true bearing. When variation is West, add to the true bearing.
| Wind: | Wind ± Variation = 320° – 12° = 308/10 |
| TRK: | TRK ± Variation = 350° – 12° = 338° |
To find the Crosswind and Headwind components, Heading required, Ground speed and Time, follow thse steps.
-
On the wind side of your CR2 computer, Point the TAS
marker on the middle circle, to the IAS on the outer marker.
-
On the inner circle, place the wind speed against the
TC
marker, and using a pencil, mark down the wind speed
-
Turn the inner circle until the TRK meets the marker
-
Find the Crosswind and Headwind components
XW: ~5kts HW: ~7kts
-
Locate the XW value on the outer circle, then look at the middle circle to find the nearest whole degree. This represents the amount of drift.
Drift: 3° -
For a left crosswind, add the drift to the TRK to determine Heading (HDG)
For a right crosswind, subtract the drift from the TRK to determine HDG.HDG: TRK ± Drift = 338° + 3° = 341° -
To find ground speed, subtract the headwind, or add the tailwind component to the IAS
GS: IAS ± HW = 110kts – 7kts = 103kts -
To find time required to travel a distance, use this formula:
Time = Distance ÷ Ground Speed