INSTRUMENTS FLIGHT PLANNING
Your action is:
Plot 235o/65 kts on windface.
Set new course of 139o on TC mark.
Note a RCW = 65 kts and TW = 7 kts.
Based on a guide = number of 5; 65/5 = 13º right crab.
Turn to 152o (139o + 13o R) at 0908.
Estimate GS = 307 kts.
Therefore, ETA to AMG = 0926.
Once the wind (235/65) is determined it is immediately applied to the next leg in order to make
an appropriate turn (152o). To continue, an ETA is predicted (0926) based on a wind derived
Once again, we are applying DR principles. We use the best wind information available and
predict what happens on the subsequent leg. Use of the CR-2 is encouraged to increase
Theoretically, the entire route could be flown in this manner. Of course, winds do change and
so, over a long flight, accuracy is degraded. By applying fundamental DR principles such as
speed, time, distance, and wind, we can predict with reasonable accuracy our position and the
time of arrival.
Do not assume DR is strictly used as a last resort when everything else has gone wrong. You, as
the NFO, should be able to predict where the aircraft is at a certain time (ETAs) and constantly
update the wind. If you are on a leg that is too short to do an accurate GS check, as long as you
have updated wind information, you can use it to predict a GS.
3-6 SITUATIONAL AWARENESS