Vehicle Countermeasure Flares And Spoofing

Vehicle Countermeasure Module (Flares and Missile Spoofing)

Source-verified 2026-06-21 against master 0139a346. Paths relative to Missions/[55-2hc]warfarev2_073v48co.chernarus/ unless noted. Arma 2 OA 1.64.

The CM module (Client/Module/CM/, by Maddmatt) is the vanilla-Arma-2 vehicle countermeasure system: when an air vehicle is locked by a guided missile it ejects flares from its model's flare_launcher selections and probabilistically spoofs the incoming round by jittering the missile's heading. It is a client-local, vanilla-only system gated by WFBE_C_MODULE_WFBE_FLARES. It is distinct from the IRS IR-smoke module (Common/Module/IRS/, ground vehicles, irLock ammo) which has its own page and explicitly disclaims the CM module (IRS-IR-Smoke-Missile-Countermeasure.md).

Module gate and the two code paths

The CM module only compiles and wires up under the vanilla branch. On Operation Arrowhead the module is never compiled; instead built aircraft have their native OA countermeasure magazines stripped when the gate is off.

Path	Condition	Effect	Citation
Compile CM functions	WFBE_C_MODULE_WFBE_FLARES > 0 && WF_A2_Vanilla	Calls CM_Init.sqf (compiles CM_Countermeasures, CM_Flares, CM_Spoofing)	Client/Init/Init_Client.sqf:913; Client/Module/CM/CM_Init.sqf:1-3
Module constant default	WFBE_C_MODULE_WFBE_FLARES = 1	0: disabled, 1: enabled-with-upgrade, 2: always enabled	Common/Init/Init_CommonConstants.sqf:811
OA removal	!WF_A2_Vanilla, module 0 or side lacks upgrade	WFBE_CO_FNC_RemoveCountermeasures strips native CM magazines	Client/Functions/Client_BuildUnit.sqf:351-360

The OA removal helper inspects the built aircraft's config and removes any 60/120/240Rnd_CMFlare[_Chaff]_Magazine turret magazines when CMFlareLauncher is among its weapons (Common/Functions/Common_RemoveCountermeasures.sqf:11-17). On vanilla, WFBE_CO_FNC_RemoveCountermeasures is bound to an empty closure (Common/Init/Init_Common.sqf:156), so the script CM system below is the only countermeasure on vanilla.

Wiring: how a vehicle gets the system

Each unit's init applies the CM event handler in the vanilla branch, switching on the module mode:

Mode	Behavior	Citation
1 (enabled-with-upgrades)	Only if the side owns WFBE_UP_FLARESCM: ExecVM CM_Set.sqf, add incomingMissile EH {_this Spawn CM_Countermeasures}	Common/Init/Init_Unit.sqf:136-141
2 (enabled)	Always: ExecVM CM_Set.sqf, add the same incomingMissile EH	Common/Init/Init_Unit.sqf:142-145

The vanilla branch is itself gated on WFBE_C_MODULE_WFBE_FLARES > 0 && WF_A2_Vanilla (Common/Init/Init_Unit.sqf:100). The OA build path adds an unrelated IncomingMissile EH to HandleAlarm only when the aircraft's incommingmissliedetectionsystem config value > 8 (Client/Functions/Client_BuildUnit.sqf:350) — that is a separate alarm system, not the CM flare pump.

Per-vehicle state: FlareCount and FlareActive

CM_Set.sqf seeds two object variables on the vehicle after commonInitComplete plus a 2s settle delay:

Variable	Initial value	Meaning	Citation
FlareCount	WFBE_C_UNITS_COUNTERMEASURE_PLANES if isKindOf "Plane", else ..._CHOPPERS	Remaining flares this vehicle can dispense	Client/Module/CM/CM_Set.sqf:7-8
FlareActive	false	Re-entrancy lock so a single incoming missile triggers only one volley	Client/Module/CM/CM_Set.sqf:9

If the vehicle is isNull the script exits without seeding (Client/Module/CM/CM_Set.sqf:4).

Default capacities

Constant	Default	Applies to	Citation
WFBE_C_UNITS_COUNTERMEASURE_PLANES	64	Fixed-wing (isKindOf "Plane")	Common/Init/Init_CommonConstants.sqf:948
WFBE_C_UNITS_COUNTERMEASURE_CHOPPERS	32	Helicopters / other Air	Common/Init/Init_CommonConstants.sqf:949

Rearm reset

Common_RearmVehicle.sqf (the vanilla rearm path; on OA RearmVehicle binds to Common_RearmVehicleOA.sqf instead — Common/Init/Init_Common.sqf:76) re-seeds FlareCount whenever an Air vehicle is rearmed, switching on the same module mode and re-applying the plane/chopper default:

Mode	Rearm reset	Citation
1	Re-seed only if side owns WFBE_UP_FLARESCM	Common/Functions/Common_RearmVehicle.sqf:19-24
2	Always re-seed to plane/chopper default	Common/Functions/Common_RearmVehicle.sqf:25-28

Incoming-missile detection (CM_Countermeasures)

The incomingMissile event handler spawns CM_Countermeasures with [_vehicle, _missile]. The handler gates and fires the flare volley:

Step	Condition / action	Citation
Altitude gate	alive _vehicle and (getPos _vehicle) select 2 > 5 (above 5 m AGL)	Client/Module/CM/CM_Countermeasures.sqf:5
AirLock detection	Reads CfgAmmo >> _missile >> AirLock; proceeds only if == 1 (an air-locking, i.e. radar/IR-guided, round)	Client/Module/CM/CM_Countermeasures.sqf:7-8
Re-entrancy	Proceeds only if FlareActive is false; immediately sets it true	Client/Module/CM/CM_Countermeasures.sqf:6,8,10
Driver warning	If driver _vehicle == player, vehicleChat "WARNING: incomming missile!"	Client/Module/CM/CM_Countermeasures.sqf:11
Flares available?	Only if FlareCount > 0 does it dispense	Client/Module/CM/CM_Countermeasures.sqf:12-13
Spoofing	_this Spawn CM_Spoofing (with [_vehicle, _ammo, _enemy])	Client/Module/CM/CM_Countermeasures.sqf:14
Flare volley	Loop _i = 0 while _i < 8: [_vehicle] Call CM_Flares; sleep 0.3 (8 bursts at 0.3 s)	Client/Module/CM/CM_Countermeasures.sqf:15-18
Release lock	FlareActive set back to false after the volley	Client/Module/CM/CM_Countermeasures.sqf:20

Note the EH passes the whole _this array to CM_Spoofing ([_vehicle, _ammo, _enemy]), but only [_vehicle] to each CM_Flares call.

Flare deployment (CM_Flares)

Each CM_Flares call dispenses one flare per flare_launcher selection found on the vehicle model and spawns the visual emitters:

Element	Value / behavior	Citation
Muzzle velocity	25 m/s baseline; 150 if isKindOf "Plane"	Client/Module/CM/CM_Flares.sqf:6-7
Launcher discovery	Counts flare_launcher%1 selections (starting at 1) until selectionPosition returns [0,0,0]	Client/Module/CM/CM_Flares.sqf:8-9
Per-launcher decrement	FlareCount = FlareCount - 1 each launcher iteration	Client/Module/CM/CM_Flares.sqf:12-13
Flare object	"FlareCountermeasure" createVehicleLocal at the launcher world position; velocity = launch direction (flare_launcher%1_dir) × muzzle velocity + vehicle velocity	Client/Module/CM/CM_Flares.sqf:14-22
Smoke emitter	#particlesource billboard (Universal particle set) at the flare, setDropInterval 0.02	Client/Module/CM/CM_Flares.sqf:25-28
Spark emitter	second #particlesource, setDropInterval 0.001	Client/Module/CM/CM_Flares.sqf:30-33
Light point	#lightpoint attached to the flare, amber color [1, 0.5, 0.2], brightness 0.1	Client/Module/CM/CM_Flares.sqf:35-39
Auto-cleanup	All emitters + flares spawn { sleep 4.5 + random 1; {deleteVehicle _x} forEach _this }	Client/Module/CM/CM_Flares.sqf:43-45

Because CM_Countermeasures calls CM_Flares 8 times and CM_Flares decrements FlareCount once per flare_launcher selection, a single incoming-missile event spends 8 × (number of launcher selections) flares from the pool. All objects are createVehicleLocal / local emitters, so the effect is purely client-side and not network-replicated.

Missile spoofing (CM_Spoofing)

Run in parallel with the flare volley, CM_Spoofing attempts to defeat the tracking missile by perturbing its heading:

Step	Condition / action	Citation
Engine gate	Only if alive _vehicle && isEngineOn _vehicle	Client/Module/CM/CM_Spoofing.sqf:7
Acquire missile	_missile = nearestObject [_enemy, _ammo]	Client/Module/CM/CM_Spoofing.sqf:8
Arming trigger	waitUntil { (_missile distance _vehicle) < (speed _vehicle) * 1.5 } (waits until the round closes to within ~1.5 s of the vehicle's own speed)	Client/Module/CM/CM_Spoofing.sqf:9
Defeat probability	_prob = 25 + random 75 vs _chance = random 100; spoof only if _prob > _chance	Client/Module/CM/CM_Spoofing.sqf:10-12
Jitter loop	While alive _missile: _missile setDir ((getDir _missile) + (random 20 - 10)); sleep 0.1 (±10° random heading wobble every 0.1 s)	Client/Module/CM/CM_Spoofing.sqf:13-16

The probability band is 25–100% (25 + random 75), so the spoof succeeds on average ~62.5% of the time and is never below a 25% floor. When it succeeds, the missile's heading is continuously nudged within ±10° until it detonates or despawns, which tends to throw it off the lock.

Upgrade gate: WFBE_UP_FLARESCM

The CM system in mode 1 is gated by the per-side upgrade WFBE_UP_FLARESCM, which is upgrade index 9.

Fact	Value	Citation
Index constant	WFBE_UP_FLARESCM = 9	Common/Init/Init_CommonConstants.sqf:46
Upgrade label	"Custom Flares" (enabled when module == 1)	Common/Config/Core_Upgrades/Upgrades_CO_US.sqf:15
Research cost	single level, [[4500,0]] (4500 funds / 0 supply)	Common/Config/Core_Upgrades/Upgrades_CO_US.sqf:42
Prerequisite	[[WFBE_UP_AIR,2]] (Air upgrade level 2)	Common/Config/Core_Upgrades/Upgrades_CO_US.sqf:102
Research time	[100]	Common/Config/Core_Upgrades/Upgrades_CO_US.sqf:134

The same module gate WFBE_C_MODULE_WFBE_FLARES == 1 also unlocks a sibling upgrade, Aircraft AA Missiles (label at Upgrades_CO_US.sqf:25, cost [[7500,0]] at :53, prereq [[WFBE_UP_AIR,3]] at :117, time [120] at :145) — both flare countermeasures and aircraft AA missiles are tied to the same WFBE_C_MODULE_WFBE_FLARES parameter being 1. East-side and other-faction upgrade files carry the parallel [WFBE_UP_FLARESCM,1] research-order entry (e.g. Common/Config/Core_Upgrades/Upgrades_CO_RU.sqf:176).

Notes and edge cases

• Vanilla-only. The script CM system never runs on OA; OA aircraft instead rely on (or have stripped) their native engine countermeasure magazines via WFBE_CO_FNC_RemoveCountermeasures (Client/Functions/Client_BuildUnit.sqf:351-360).
• 5 m AGL floor. A missile fired at a landed or near-ground aircraft will not trigger flares (CM_Countermeasures.sqf:5).
• AirLock filter. Only rounds whose CfgAmmo AirLock == 1 trigger the system; non-air-locking ordnance is ignored (CM_Countermeasures.sqf:7-8).
• Spoofing needs the engine on. CM_Spoofing exits silently if the engine is off, even though flares may still deploy (CM_Spoofing.sqf:7).

Continue Reading

• IRS IR-Smoke Missile Countermeasure — the ground-vehicle smoke counterpart that explicitly distinguishes itself from this CM module
• Modules Atlas — the one-paragraph CM gate pointer and the surrounding client gameplay-module index
• Upgrades And Research Atlas — how WFBE_UP_* upgrade indices, costs, prerequisites and research times are structured
• Faction Root Variables Reference — per-faction WFBE_%1* variable catalog that the module gates read against
• Support Specials And Tactical Modules Atlas — broader index of the client-side tactical/support modules