Там же читаем advantages of arrowhead
http://www.defenseindustrydaily.com/...461/#arrowhead
Col. Jim Slife, a USAF special ops pilot, in a 2007 Armed Forces Journal article identifies a number of other high-altitude flight issues:
* Some helicopter missions, such as close air support (CAS), require low-altitude flight. With training, pilots could fly CAS missions from altitudes above 3,000 feet. This altitude would eliminate the environmental obstacles, as well as threats from small arms, light machine guns, rocket-propelled grenades, and the scourge of helicopter pilots, MANPADS.
* Flying at high altitudes can make it more difficult for helicopters to maintain visual contact and stay in formation, particularly if there is heavy cloud cover.
* Many helicopter countermeasure systems are optimize for operation at low altitudes and may not provide cover at high altitudes. Existing countermeasure system might have to be modified.
* A helicopter’s lifting performance is reduced with altitude. Helicopter engines run hotter at higher altitudes, which reduces performance. Also, the aerodynamic performance of rotor systems decreases in thinner air.
* At high altitudes, there is a blind spot under the helicopter that can’t be visually scanned. This makes the helicopter’s underbelly vulnerable to attack.