Timing Corrections

LOW-LEVEL AND TACTICAL FORMATION

CHAPTER ONE

will keep you on course. As you get closer to your selected point, recheck your

heading system and select another feature that is on course.

Keep doing this until you find and positively identify your turnpoint or turn on time.

Use funneling features between 10 and 2 o'clock to steer back to course. You may

find roads on either side of you that converge on your checkpoint. A valley between

two ridgelines may lead you directly to your checkpoint. Funneling features are

relatively common, but they might not be obvious. Study your chart for possible

funneling features prior to flight. Again, make sure you know where you are and

where you should be before making a course correction. A good technique is to

confirm your current position by at least two other references before making a course

correction.

If you cannot find any features between 10 and 2 o'clock, use a technique known as

Standard Closing Angle (SCA). SCA is calculated by dividing 60 by your GS in

NM/min. This results in an SCA of 20 for 180 knots GS. The SCA is then applied

to your planned heading and held one minute for every mile you are off course. You

could also apply double the angle for half the time (40 for 30 sec per mile off course)

but as you increase the heading corrections, you will increase the timing error your

correction induces. Making too rapid or too acute a correction may affect your

timing. For instance if you were 2 miles left of course and chose to turn 90 right for

2 miles and then 90 left on course, you would increase your overall running time by

40 seconds at 180 knots GS.

An example of a course correction follows: you confirm you are 2 miles left of

course and want to correct to course minimizing timing errors. You cannot find a

feature in the distance that is on course and you cannot find any funneling features to

steer back to course. You decide to use the SCA to correct. With 180 knots GS you

would turn 20 right for 2 minutes (or 40 right for 1 minute). The correction you

choose depends on the length of the leg on which you are making the course

correction. A short leg may not allow you to make a 2-minute correction. When

back on track, analyze why you got off track. Were you holding the desired heading

or did you let your heading drift? Is your RMI/HSI working properly or do the winds

appear different than planned? Whatever you determine, apply the appropriate

corrections to avoid repeating your mistake.

Timing Corrections. Timing corrections are simply a matter of changing your GS

for a period of time or off-course maneuvering. Off-course maneuvering will change

the distance you fly which will affect your timing. All timing corrections should be

made prior to the IP. No timing corrections shall be made from the slowdown to the

DZ/LZ. The following methods are recommended:

Off-Course Maneuvering. Off-course maneuvering works well on routes that

are circular (semicircular) or have turns of more than a few degrees between

legs.

LOW-LEVEL NAVIGATION 1-23