INTERCEPT PROCEDURES TEXTBOOK
Step 3: Countering the Drift
After analyzing the drift, the next step is to counter it. Once DOP is determined, turn in the
direction of drift to counter the drift and place the bogey on the 30º scribe opposite the direction
of drift (ex: right drift goes to 30ºL AO). Now wait for subsequent drift.
Step 4: Estimate cut, TA, and BH
Now the fighter can make an initial estimation of cut, TA and bogey heading. After
displacing the bogey to 30º angle-off, make a BRA call and assume the bogey is on CB. The cut
will be equal to twice the AO (since CB = 1/2 cut). Now estimate the bogey heading, which will
become important in the event of a lost contact in the counterturn. Realize that these are
estimates and require confirmation (i.e., no subsequent drift).
It is likely that the fighter will not steady on a cardinal heading when placing the bogey
bearing on a scribe. For example, the fighter initially steadied on a heading of 342º and the
bogey drifts to 344º in 4 nm. The fighter turns to a heading of 014º to place the bogey 30ºL of
the nose (due to left to right DOP).
Step 5: Reanalyze Drift and Make Further CCC's
Continue to analyze and counter drift until no drift is observed. Inward drift (inward
meaning drift towards the fighter's nose) indicates that the actual TA is greater than estimated.
Outward drift (drift away from the nose) indicates that the actual TA is lower than the estimate.
Regardless of the direction of drift, any drift at all
indicates that a collision intercept has not been achieved.
The fighter must react immediately to stop the drift.
For these secondary corrections, counter inward drift by displacing the bogey outward
(outward meaning away from the fighter's nose) by 20º and counter outward drift by displacing
the bogey inward (towards the nose) by 10º. The reason we place the bogey further out when
target aspect is increasing is because the fighter needs to ensure TA does not get so large that the
Sparrow shot is lost due to having greater than 45º of TA. In all cases, 1º of drift (in other words,
any drift at all) is all that is required for a secondary correction.
Move the bogey in by 10º and out by 20º
One last point on unknown CCCs. If the contact shows up late after the fighter has made
CCCs based upon GCI calls, the fighter should turn to put the contact on collision (based upon
assumed TA) if the contact is more than 2 degrees from the expected collision AO. For example,
if the contact is assumed to have 20 right TA and is placed on collision per GCI calls, the fighter
would expect to see the contact show up at 20 left AO. If the contact showed up at 23 AO, the
fighter would turn to put the contact at 20 AO and make further CCCs as required by drift.