INTERCEPT PROCEDURES TEXTBOOK
UNIT 4: DISPLACEMENT AND COUNTERTURNS
IP-9: DISPLACEMENT TURN FUNDAMENTALS
Lateral Displacement / Turning Room
Obviously, a collision course will not be continued all the way to a midair. It will be broken-
off at some range to permit the fighter to execute a turn in order to arrive in the bogey's rear
quarter. By knowing TA and slant range, we can then calculate lateral displacement, also known
as turning room.
The weapons officer must compute TA correctly prior to breaking the collision course.
Therefore, here at VT-86, you will stop making collision course corrections 2 miles prior to the
displacement turn. This will allow time to observe drift and, if necessary, update TA prior to
commencing the displacement turn.
The displacement turn (DT) is the turn made by the fighter to break collision course. It will
reorient the flight path in order to gain, maintain, or slow the rate of loss of lateral separation.
Following extensive, and often dangerous, flight testing, we pushed the T-39N to the edge of
the envelope and concluded that 20,000 feet (roughly 3 1/2 nm) is the ideal amount of turning
room for the reattack intercept. As you can imagine, the T-39N will need more lateral
displacement than high performance fighters.
Remember the lateral displacement formula:
TA x SR x 100 = LD
An example of the amount of turning room available for certain target aspects is shown in
5º TA x 10 nm x 100 = 5,000' LD: not enough turning room
20º TA x 10 nm x 100 = 20,000' LD: adequate turning room
30º TA x 10 nm x 100 = 30,000' LD: too much turning room