This article is a (hopefully not too boring) list of definitions, some of which have been already discussed in the past. A thorough understanding of definitions, acronyms and relations is unfortunately a necessary evil.
Basic Definitions: Recap
The following concepts have been discussed in-depth already in previous articles. They are reported for completeness’ sake and as a refresher.
Definitions about the timeline are from different sources; the definitions about the geometry instead are reported in the previous part of this series.
Definitions related to the Timelines
Note: these definitions were discussed in the article about the BVR Timeline.
- DR= Decision Range: “The minimum range at which a fighter can execute the briefed notch maneuver, remain there for a pre-briefed period of time in an attempt to defeat spikes, and then execute an abort maneuver. This maneuver will kinematically defeat any missiles shot at the fighter and momentarily keep the fighter outside the threat’s maximum stern weapons employment zone (WEZ) once the abort maneuver is completed. This definition does not address an adversary’s capability to eventually enter a stern WEZ by continuing to run down the fighter.” (Korean AF BEM A1-41)
- FR = “FR (factor range)—During merge tactics, the minimum acceptable distance between the group being merged with and the next the nearest group. Groups outside of this range are unlikely to affect the merge with the targeted group. FR should allow engaging and killing the targeted group, egressing tail aspect to the second group, and remaining outside that group’s maximum stern WEZ. FR is driven by threat weapons capability, fighter weapons capability, closure, and proficiency.” (AFTTP 3-1.1)
- MAR = “Minimum abort range (MAR) – The range at which an aircraft can execute a maximum performance out/abort manoeuvre and kinematically defeat any missiles and remain outside an adversary’s WEZ.” (AFTTP 3-1.1)
- DOR = “DOR (desired out range)/MOR (minimum out range)—Range from the closest bandit where an aircraft’s “out” will defeat any bandit’s weapons in the air or still on the jet and preserve enough distance to make an “in” decision with sufficient time to reengage the same group with launch-and-decide tactics. This also gives trailing elements a “clean” picture, reducing identification problems when targeting.” (AFTTP 3-1.1)
- LAR= “is a three-dimensional volume of space around a hostile aircraft into which the fighter must fly in order to have a chance to successfully employ its weapons. The fighter will maneuver in altitude, airspeed, and heading in order to achieve the best weapon solution for his opponent. The LAR is largest (i.e., longest RMAX) with 0 TA, at high airspeed and high altitude and is smallest (i.e., shortest RMAX) in the rear quarter at low altitude and low airspeed. Missiles like altitude, airspeed, and closure to achieve maximum kinematics.” (P-825 12-1)
- Skate = “Informative or directive call to execute launch-and-leave tactics and be out no later than desired out range (DOR)/minimum out range (MOR).” (AFTTP 3-1.1)
- Short Skate = “Informative or directive call to execute launch-and-leave tactics and be out no later than minimum abort range (MAR)/decision range (DR).” (AFTTP 3-1.1)
- Banzai = “Informative/directive call to execute launch and decide tactics.” (AFTTP 3-1.1)
- Out (w/direction)= “Informative call indicating a turn to a cold aspect relative to the known threat.” (AFTTP 3-1.1)
- Abort (w/direction)= “Abort is maximum performance, 135 degree overbank, nose slicing turn to put the threat at the6 o’clock position and accelerating to .7 IMN” (P-825 14-45)
- Crank (w/direction) = “F-Pole maneuver; implies illuminating target at radar gimbal limits.” (AFTTP 3-1.1)
- Notch (w/direction) = “Directive (informative) for an all-aspect missile defensive maneuver to place threat radar/missile near the beam.” (AFTTP 3-1.1)
- Pump (w/direction) = [AF] “A briefed maneuver to low aspect to stop closure on the threat or geographical boundary with the intent to reengage.” (Korean AF BEM A1-41)
- Bugout (w/direction) = [AF] “Separation from that particular engagement/attack/operation; no intent to reengage/return.”
- Extend (w/direction) = [AF] “Short-term maneuver to gain energy, distance, or separation normally with the intent of reengaging.”
- A-Pole = “The distance from the launching aircraft to the target when a missile begins active guidance.” (AFTTP 3-1.1)
- E-Pole = “The range from a threat aircraft that an abort maneuver must be accomplished to kinematically defeat any missile the bandit could have launched or is launching.” (AFTTP 3-1.1)
- F-Pole = “F-Pole is the separation between the launch aircraft and the target at missile endgame/impact.” (AFTTP 3-1.1)
- M-Pole = (not applicable) Fighter-Target range when the missile activates its seeker (MPRF).
- N-Pole = Notch-Pole.
- WEZ = Weapons Engagement Zone. “The three-dimensional volume of airspace around a fighter into which the hostile aircraft must fly to employ weapons.” (P-825 15-2)
Definitions related to the Geometry
- FH, Fighter Heading. “Heading of the fighter which, if extended through space, defines the fighter’s flight path”.
- FFP, Fighter Flight Path, “The logical extension of the direction of the fighter’s travel through space on its current FH”.
- BH, Bandit Heading. “Heading of the intercepted aircraft”.
- BFP, Bandit Flight Path, “the logical extension of the bandit’s travel through space on the current BH”.
- BR, Bandit Reciprocal Heading or Bandit Recip, it “is 180 degrees in the opposite direction from BH”.
- BB, Bandit Bearing. “Line of sight (LOS) bearing between the fighter’s position and the bandit’s position. BB is independent of both FH and BH”.
- SR, Slant Range. “Direct LOS distance between fighter and bandit”.
- Rate of Closure (VC), “Sum of the components of fighter and bandit velocities that contribute to downrange travel”.
- Lateral Separation “is the horizontal distance from the fighter to the BFP”. It is expressed in thousands of feet and is calculated as Target Aspect * Slant Range * 100.
- Vertical Separation (VD), “is the perpendicular distance the fighter is located above or below the bandit’s flight path”. It is calculated as the LS. VD = Elevation * SR * 100.
- Antenna Train Angle (ATA) is defined as “the position left or right of the fighter’s nose on the radar attack display”.
- Target Aspect (TA) is defined as “The bandit’s perspective pertinent to the fighter”. “The angle from the bearing line of the fighter to the nose of the target”.
- Aspect Angle (AA) is the supplementary angle of the TA. “The angle from the bearing line of the fighter to the tail of the target”.
- Cut: “The angle from fighter heading to bogey reciprocal.” (FH to BR).
- DTG (or HCA) (Degrees To Go or Heading Cross Angle): “is the shortest number of degrees the fighter needs to turn to parallel the bogey’s flight path, or turn to the bogey’s heading.”
- DOP: “is the direction the bogey would pass from one side of the fighter’s flight path to the other.”
Relations, Formulas and Synonyms
- Cut = Fighter Heading (FH) to Bogey Reciprocal (BR)
Cut = FH to BR
- Target Aspect (TA) = Bogey Reciprocal to Bogey Bearing
TA = BR to BB
- Collision Bearing (CB) when co-speed = ½ Cut
CB = ½ Cut
- Collision Bearing = Collision Antenna Train Angle (CATA)
CB = CATA
- Lateral Separation or Lateral Displacement
LS = TA x SR x 100
- Vertical Separation or Vertical Displacement
VD = Elev x SR x 100
- Angle Off (AO) = Antenna Train Angle
AO = ATA
- Degrees to Go (DTG) = Fighter Heading to Bogey Heading
DTG = FH to BH
- Degrees to Go (DTG) = Heading Crossing Angle (HCA)
- If SR → 0, TA and ATA increase.
The best part: Maths!
Note: The following relations are taken from the official documentation but they are not always applicable “out of the box”. They are meant to be used by the RIO for assessing the parameters in his head.
This passage clarifies the potential issue:
[..] The computations require little mathematics beyond simple arithmetic. However, certain angular values are labelled either left or right with reference to either the fighter or enemy aircraft’s compass heading. The determination of Left-Right labels for Target Aspect, Antenna Train Angle, and Cut may be accomplished by a simple rule. Unfortunately, this rule does not hold true for all conditions, due to the discontinuity of compass values at a heading of North (3600). Under this condition the problem of reference labelling (RIGHT or LEFT) of values quickly becomes non-trivial for the neophyte RIO.NAVTRAEQUIPCEN 71-C-0219-1 p7
In some cases, the modulo would have been better, in others, “mentally checking” directions and labels is simply more efficient.
Usually the RIO starts the intercept knowing at least the first three of the following parameters (ATA is obtained from the TID as soon as there is radar contact):
|Bogey Bearing||BB||GCI / AIC|
|Bogey Heading||BH||TID or GCI / AIC|
|Antenna Train Angle (or Angle Off)||ATA / AO||TID|
Starting from those values, other parameters can be easily calculated:
BR + 180° (if BH < 180°)
BR – 180° (if BH > 180°)
|BR – BB|
TA is labelled Left (L) or Right (R) if BB is Left or Right of BR.
BB + TA (if TA is Right)
BB – TA (if TA is Left)
|FH – BR|
Cut is labelled Left (L) or Right (R) if BR is Left or Right of FH.
|Degrees To Go||DTG||
180° – Cut
Cut label is not considered
|Antenna Train Angle||ATA||
|FH – BB|
Labelled Left (L) if BB < FH
Labelled Right (R) if BB > FH
Note: ATA is displayed on the TID but this formula is useful when there is no radar contact.
BB = FH – ATA (if ATA is Left)
BB = FH + ATA (if ATA is Right)
Note: useful if no tactical controller is available.
These relations are fundamental but not always necessary as some information can be obtained by means of the avionics or the AIC/GCI. Since there can be exceptions, the RIO should be able to calculate every parameter with the data he can extrapolate.
These are to simple scenarios where the RIO has to calculate those parameteres on his own:
- Lack of controller: if a controller is not present, the BB has to be calculated, or different formulas used;
- Ground (or Air) Controlled Intercept: the RIO must be able to perform most of the intercept guided by the GCI/AIC (and even without radar contact). This means calculating the necessary parameters using information from the tactical control.