Their titles are pretty much self explanatory, but there are refinements within their areas of specialization that ought to be mentioned.Air Troop are the free-fall parachuting experts. They specialize in high-altitude, low-opening (HALO) descents, an effective means of arriving in their designated area of operations without the enemy on the ground being alerted by the presence of a low-flying aircraft. At night, they will leave the aircraft at 25,000 feet and breathe oxygen from cylinders on their chest packs, only opening their parachutes when they are 4,000 feet above the ground. During a daylight jump from the same altitude they will shave another 1,000 feet off the height at which they open their chutes, bringing them in from around 3,000 feet. From that height they are down and in position before an enemy, even assuming he has seen them, has had time to blink. When all four troops of a squadron are jumping at night, Air Troop jump at lower altitude, say around 13,000 feet. They will then mark out the landing strip for the squadron while the pilot circles.
