BVR Intercept Geometry

GROUP BVR Intercept Geometry

Intercept Geometry. In air combat, understanding the relative and absolute
geometry of you and the bandit is immensely helpful to combat effectiveness.
Remembering these terms is critical to effective BVR employment.

Positional Geometry. Positional Geometry deals with the geometric relations
between aircraft. There are three main positional terms:
  1. Antenna Train Angle (ATA): The number of degrees the defender is off the boresight of the attacker.
  2. Target Aspect (TA): The angle measured from the nose of the target to the position of the attacker. Also the ATA for the bandit.
  3. Aspect Angle (AA): The angle measured from the tail of the target to the positionof the attacker. Remember that AA+TA = 180°.
  4. Slant Range: The range between the fighters in 3D space. Also simply known as range
  5. Heading Cross Angle HCA: The angle formed by the intersection of the bandit and fighter flight paths.
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6. Aspect Zones. Aspect itself is typically divided into 4 zones: hot, flank,​
beam, and drag:

HOT: Hot targets have a TA between 0 and 30°, which is a AA of 180 to 150°
FLANK: Flank aspect refers to a TA between 30 and 60° TA, which is an AA of 150
to 120°
BEAM: Beam aspect refers to a TA between 60 and 120°, which is a AA of 120 to
60°
DRAG: Drag aspect refers to a TA between 120 and 180°, which is an AA of 0 to 60°

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Pursuit Curve. Pursuit curves define the relationship between your nose
position, and the bandit. There are three available attack pursuit courses: lead, lag
and pure.

With his nose pointed in front of the defender (such as in the case of a gunshot), you
are in lead pursuit.

If your nose points behind the defender, you are in lag pursuit.
If your nose points at the adversary, you are in pure pursuit.

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Example:

Now we have to complete the intercept, get a VID and shoot this guy. Since we need to get a VID to shoot these bandits, the best intercept to fly is a stern conversion. By rolling out the bandit’s 6 o’clock, we will have time to pick up a tally on the bandit and get a shot. If we go in at high aspect, we may not see the bandit until we are inside Rmin for a missile shot.

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DCS F-16C stern conversion intercept steps:
  1. Switch over to STT (Single Target Track) radar mode to obtain aspect angle of bandit.
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2. Turn opposite the aspect angle to get turning room on the targets. In other words, if the aspect is 160° left aspect, then you need to turn right to move the targets to the left side of the scope. Do not turn so far that you take them off the scope. Just turn far enough to put them about 40° on the scope. The below image shows how you make this turn. Notice the figure has a god’s-eye view and a radar view. All you are going to get in the jet is a radar view. It is up to you to use your gray matter to convert a radar display to a god’s-eye view of the intercept.​

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Now is a good time to show what happens if you don’t analyze the aspect properly and turn the wrong way for offset. Let’s say the aspect was 160° left and you turned left for offset. Would this work? The answer is no, and below shows why. If you turn the wrong way, you will actually be taking away your turning room rather than increasing it. This will not be obvious by just looking at the target’s position on the radar scope.​
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3. The next step is to hold the targets at 40° on the scope and drive in. In order to hold the targets at 40°, you may have to check turn into them occasionally. The explanation for this is a little outside the scope of this book, but put simply, a target that is not on a collision course will always drift away from you. Think about this statement in driving terms. If you are driving on a two lane highway, you will notice that the oncoming traffic moves across your windshield and then suddenly flashes by. The oncoming traffic never just stays in the exact same spot on the windshield unless you are about to end up with chrome between your teeth. The same thing applies in air combat. During an intercept, you are driving the target away from a collision angle in order to get turning room. That means that the target will keep drifting farther away from you unless you turn to hold it at a particular angle.​

In order to perform an intercept, all you have to do is follow the procedures. It’s just like baking a cake. You don’t have to understand the chemical process, you just have to follow the steps.

4. When you get to 10 miles from the bandits, go to STT and turn to put the target you are locked to in the HUD. This is the part of the intercept where things get serious. There are two reasons that we put the target on the nose at 10 miles. The first reason is so we can get a tally on the target. In the HUD, we have a Target Designator box with a target in it. The next image shows a HUD with the TD box labeled.​
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The other reason we turn to put the target on the nose at 10 miles is to get small. It is much harder to see a jet that is pointing at you because there is less surface area to look at.

When we get a tally on the target, the intercept is over and it is time to use BFM. Remember in this fight that we only have a TD box on one of the two targets. As soon as we get a tally on the bandit in the HUD, we need to look for the other guy. Don’t make the mistake of putting your eyes into the “random flail” mode. If the bandits have stayed in a visual formation (which is about 90% of the time), then the other bandit will be just outside the HUD when you get a tally on the guy in the TD box.

The Engagement Phase
Now that we have two MiG-29s in sight, we must kill the one in the TD box fast and then go 1V1 with the other Fulcrum. If you can’t smoke the bandit in the TD box fast, then you have to beat it. For this reason, be ready to shoot as soon as you can VID the target. Shoot and kill and, if you miss, do the “Jane Fonda routine” and give peace a chance. While you’re giving peace a chance, be at high speed and high angle-off from the Fulcrums. Again, you must resist the temptation to enter a turning fight.

Let’s say we do kill one of the Fulcrums at the merge-now what?

When entering a dynamic turning fight against a very maneuverable aircraft in an F-16, you need to remember one concept, lead turn. My game plan if I’m committed to stay and fight is to use a nose low slice at the pass and lead turn at every opportunity. Once you turn 180°, how-ever, your escape window is shut and unless something strange happens (like the MiG is hit by a meteor), you must kill the bandit in order to survive the fight. In a lead turning fight, you must initiate your turn on the Fulcrum prior to passing his 3/9 line. In addition, strive to be at corner airspeed on the initial turn at the merge.

While you are in this lead turning fight with the Fulcrum, think weapons. A Sidewinder can fly better BFM than you can, so put one in the air if you get a chance. Keep in mind, however, that at high aspect when you are in missile parameters on the MiG-29, he may also have you in parameters for his missile. Again, you must fight hard because it is him or you once you enter a turning fight.
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