Draw a line from 1300Z DR position, 37º30’N 021º30’W to PORT SANTO NDB and measure the track (136ºT) and distance (375nm).

Nav Computer: Centre dot on TAS (450 kts using the high speed side of the slide), rotate to put wind direction (360ºT) on HEADING index and mark wind on centre line 30kts below centre dot (over 420 kts).

Rotate to put track 136ºT next to the HEADING index; read the drift under wind mark: 3º right (Stbd), put the track 136ºT under the drift 3º right and note that the drift is still 3º right.

On heading 133ºT the 3º right drift will give the required track (136ºT) and the groundspeed is under the wind mark: 473kts.

On reverse side of nav computer put the 60 on the inner main scale next to the groundspeed (473kts) on the outer main scale.

Go to distance (375nm) on the outer main scale and read elapsed time next to it on the inner main scale (47½ minutes). ETA PORT SANTO NDB is 1347½Z.

OR

Plot position.


Measure True Bearing to Port Santo = 135°T
Calculate GS = 470 KTS
Plot distance between points and measure along line of longitude
= 6° 20' (of Latitude)
= 380 NM
380 NM @ 470 KTS = 48.5 MINUTES
1300 + 48.5 = 1348 UTC