IP-17: Lead Collision Intercepts (Attack-Reattacks)

INTERCEPT PROCEDURES TEXTBOOK

IP-17: LEAD COLLISION INTERCEPTS (ATTACK-REATTACKS)

Introduction

Modern tactical doctrine does not always allow for purely rear quarter attacks. The fighter must

be able to employ forward quarter weapons to maintain a tactical advantage over adversaries. The

need for the aircrew to control the intercept, determine target aspect, establish collision bearing, and

accurately achieve proper firing parameters for all weapons remains the highest priority.

Sparrow Attack

The fighter will apply the same basic procedures that have been utilized thus far in the reattack or

pursuit intercept. To provide guidance for an AIM-7 Sparrow, the fighter must place the radar in the

automatic tracking mode. Acquiring a lock (single target track/STT) will furnish the missile with the

continuous wave guidance necessary for successful employment.

Factors Affecting Success

Forward quarter weapons such as the Sparrow guide on a Doppler frequency shift for their

targeting. As you will recall from your radar theory class, a doppler shift is the change in a pulse's

frequency caused by the downrange travel to or away from the fighter--also known as closure.

Therefore, targets with greater components of closure (lower target aspects) will have a higher

probability of being targeted accurately than those with lower components of closure (higher target

aspects).

The "probability of kill", or Pk, is a measure of the likelihood that a missile will guide to, impact

and destroy the target. Higher closure rates (ROC) will increase the Pk for the Sparrow, as well as

the maximum range that this missile can be employed.

Closure rates, and hence max range, can be increased three ways: make a faster missile, fly the

aircraft faster or lower the target aspect. At VT-86, the aircraft speed will be limited and our

simulated missiles fly at a constant velocity. Therefore, a change in target aspect is the only way we

can affect maximum range and Pk.

Lead Collision

Recall from IP-1 that lead pursuit places the fighter's nose in front of the target's nose to decrease

range and increase closure. Lead collision is still a form of lead pursuit, but the fighter's nose is

placed in front of the target by an amount that allows the faster missile to complete its own collision

intercept. Because the missile is faster than the target, it will fly a longer distance than the target to

the impact point (similar to a fighter with a speed advantage).

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