July 28, 2011: In a rare incident, an American Ch-47 helicopter was hit by an RPG rocket and forced to crash land near a U.S. base in eastern Afghanistan. Two of the twenty people on board were slightly wounded (by RPG fragments). The RPG is a rocket launcher, and the rockets are unguided. Hitting anything as large as a helicopter, at more than a hundred meters, is mainly a matter of luck.

This is the 17th helicopter to be brought down by hostile fire in the last ten years in Afghanistan. Another 84 have crashed for non-combat reasons. In Iraq, 46 helicopters were brought down by enemy fire (in addition to 76 that crashed for non-combat reasons) during seven years of much heavier combat. Because of its higher altitudes, Afghanistan is a much rougher environment for helicopters.

In most cases, helicopters are brought down machine-guns, especially heavy (12.7mm or larger) ones. The enemy has also been using portable surface-to-air missiles since 2003, including more modern models, like the SA-16 (which is similar to the American Stinger.) American helicopters are equipped with missile detection and defense (flare dispensers) equipment. Thus the most dangerous anti-aircraft weapon remains the machine-gun. However, aircraft losses to ground fire have been declining every year, mainly because of improved defensive tactics.

Helicopters are fired on about six times more frequently than they are hit, and most of those hit are only slightly damaged (and land normally). Today's helicopters are much more rugged and reliable than those in Vietnam (1966-71, the first major combat use of helicopters). There, 2,076 helicopters were lost to enemy fire (and 2,566 to non-combat losses). In Vietnam, helicopters flew 36 million sorties (over 20 million flight hours). Helicopters were used much less in Iraq, where no more than half a million hours a year were flown (to support a third as many troops as there were in Vietnam during the peak year). In Vietnam, helicopters were about twice as likely to get brought down by enemy fire. As in Iraq and Afghanistan, the main weapons doing this were machine-guns. Today's helicopters are more sturdy, partly because of Vietnam experience, and are more likely to stay in the air when hit, and land, rather than crash.