The Strela-3 is used by Hudson while on Rebirth Island to shoot down Mi-8 helicopters that are attacking his squad.
The Strela-3 is unlocked at level 30. It is vehicle lock-on only, and comes stocked with one spare missile. It serves essentially the same function as the Stinger missile from Modern Warfare 2. It pairs well with Ghost Pro, as the player using the Strela-3 can take out a single Attack Helicopter, Chopper Gunner, or Gunship alone, by firing the first missile to force the helicopter to evade with flares, then using the second to take it down entirely.