INTERCEPT PROCEDURES TEXTBOOK
Vertical displacement (feet)
Elevation X SR X 100
In the example above, the bogey is 4 high at 20 miles, therefore 4 x 20 x 100 means that the
bogey is 8000 feet above the fighter.
During real world intercepts, you will frequently be told the altitude of the bogey and must
compute the elevation in order to determine where to look for him. Therefore, you must be able
to work the vertical displacement problem in reverse. Example: The bogey is at 30,000 feet at
20 miles with the fighter level at 10,000 feet. Where do you look with your radar?
20,000' of vertical displacement
20,000 feet = 20 = 10 of elevation
20 nm x 100
A simplified statement of this formula is to drop the two zeros from the altitude difference
and divide by the slant range.
20,000 -- drop the two zeros = 200, divided by SR of 20 miles = 10 of elevation.
Rate of Closure (ROC)
The rate of closure is the sum of the fighter and bogey's true airspeeds measured along the
bearing line between both aircraft. The variables that affect the ROC are: