The SA-7 (NATO designation of "Grail" or Soviet designation of "Strela-2") is a MANPAD system - a portable shoulder launched anti-aircraft weapon system. The lethality of such a system lies in the mobility of the firer to seemingly 'pop up' at opportune times and strike at low-flying aircraft. The effect of such an element is two fold as it forces the targeted aircraft to fly above and beyond the range of the weapon, exposing it to the hazards of enemy radar or more potent surface-to-air defenses. Should the aircraft continue to fly within the range of a weapon like the Grail, it carries the greater calculated risk of being brought down from a smaller enemy below or behind the aircraft.
Similar in many respects to the American Redeye surface-to-air missile system, the SA-7 Grail has proven most accurate against low-flying aircraft and helicopters with the only major drawback being that the missile, once fired, must be trained in on a consistent heat source to score a kill. The weapon maintains a hit percentage of roughly 90%, though the HE (High Explosive) warhead is said to not accomplish much in the way of overall damage - as proven in some instances where damaged Israeli fighters were able to return to friendly airbases after receiving direct hits from Grail ground detachments during the Arab-Israeli War of 1973.
Nevertheless, the system can still be considered deadly in the event that critical systems are destroyed or damaged - in an aircraft that could be the cockpit, avionics or engine components and in rotary aircraft, that could be the cockpit, the tail rotor assembly or main rotor assembly. In any event, the use of the SA-7 Grail is even the most basically-trained of hands should still be regarded as a potential enemy threat to aircraft.