Info: Interception

Level
Expert

Interception
How plane interception works

Each time an enemy plane (i.e. a plane owned by a country that your are HOSTILE to or worse) flies into over a sector, surface ship or land unit you own, planes you have with the intercept ability will intercept them if: Neutral and friendly planes will be reported, but not intercepted.
 * 1) The incoming planes are not stealthy, or are detected.
 * 2)   The sector is within 1/2 the interceptor's range (as modified by the range command).
 * 3)   The interceptor is on no mission, or it is on air defense mission and the incoming planes are in its op area.
 * 4)   It has mobility and fuel.
 * 5)   It is at least 40% efficient.
 * 6)   It is in a suitable base:
 * 7)       Planes without VTOL ability must be at an airport that is at least 60% efficient.
 * 8)       Planes on ships may only fly if the ship can operate that kind of aircraft.

You additionally intercept anywhere else in your air defense mission op areas, but only with planes on air defense mission.

Before planes scramble to intercept incoming planes, flak fires (see Info: Flak), and any SAMs in range will be launched. One SAM is launched at each incoming plane that cost at least $1000 to build. See below for the damage that the SAM does to the plane it hits.

Enemy planes will be intercepted by up to 1 more interceptor, i.e. 1 plane will be intercepted by 2 (if available), 2 by 3, 3 by 4, etc. The highest numbered planes intercept first. Incoming missiles will only be intercepted by ABM's

Once the roster of attackers & interceptors is determined, attackers and interceptors dogfight. First escorts & interceptors fight, then planes being escorted & surviving non-aborted interceptors.

First, an attacker and a defender are chosen, then each plane on each list fights once.

Combat values
The attacker's combat value is calculated by adding up his planes attack value, and modifying it for efficiency, bomb-load, and stealth. The attack value of the plane is multiplied times the plane's efficiency, but cannot go below 1/2 of the plane-type's base value (as shown by show plane stats). (If the plane's attack value is 0, the defensive value is used instead, with a minimum of 1/2 the plane- type's defensive value)

Two is subtracted if the attacking plane is carrying bombs.

If the plane is stealthy, stealth%/25 is added.

The defender's value is calculated in the same way, except that the defensive value is always used.

Odds
Next, an odds ratio is calculated: (att/(def+att))*100.

Combat Intensity
Then, a combat intensity is rolled: (d20+d20+d20+d20)

Combat For each point of combat intensity (or until both planes are dead), a d100 is rolled. If the value is less than the odds, the defender takes a casualty, otherwise the attacker takes a casualty.

Once all combat rolls have been made, the attacker and defender are checked for aborting. If a plane is damaged below 80%, then it will have a chance of aborting. The chance to abort is (80-plane eff). (Example: a plane at 70% has a 10% chance to abort.

Missiles intercepting die after the combat is done.

Example
Suppose that a fighter 2 (30% efficient, tech 154, attack value 7) is conducting a recon mission. As it enters an enemy controlled sector, a fighter 1 (100% efficient, tech 131, defense value 4) rises up to fight it. The attacker's combat value is calculated: The defender's defense value, calculated similarly, is 4.
 * 1) 7 * (30/100) = 2.1 = 2
 * 2) 2 is less than 1/2 the base attack value of an f2 (6), so the value is changed to 3
 * 3) The attacking plane is not stealthy. No modifier.
 * 4) The attacking plane is not carrying bombs. No modifier.

The odds ratio is (3/(3+4)) = .429 = 43%

The intensity is randomly determined to be 30. A d100 is rolled 30 times. Each time that is 43 or less, the defender takes a hit. Each time it is 44 or more, the attacker takes a hit.

In our example, the attacker takes 17, the defender 13, leaving them at 13% and 87% efficiency, respectively. The attacker has an 67% chance to abort, and the defender won't. If the attacker aborts, the mission is over. Else, the attacker flies on to the next sector in his flight path, perhaps to have combat again.

ABM's ABM's do not use the normal combat procedure. They simply have a % chance of destroying an incoming warhead equal to their defensive value.