LOW-LEVEL AND TACTICAL FORMATION
1 minute. This also means you can gain or lose 6 seconds for every minute the
adjustment is made (Figure 1-11).
Time to hold
Figure 1-11 Ten Percent (10%) Method
Incremental Method. To determine the increment, first find your groundspeed
in nautical miles per minute (180 kts = 3.0 miles per minute). Multiply this by
10 to get the increment (3.0 x 10 = 30). Divide your time ahead or behind (in
seconds) by 10 to determine the number of minutes to hold the correction. For
example, if you are 50 seconds late, you must hold the 30-kt correction
(increment) for 5 minutes (50 sec/10). Note that you will gain or lose 10
seconds for every minute that you hold the increment (Figure 1-12).
Try to have your overall timing corrections accomplished by the time you arrive at the IP.
Likewise, when back on time, analyze why you got off time. Also check that you are now
maintaining the correct or new IAS (if one was required).
If you are close to continuation fuel, beware of increasing your
speed too much. The increase in fuel consumption may force an
early return to base. In this situation, it may be better to accept and
allow the timing error.
1-26 LOW-LEVEL NAVIGATION