15 - 11 15-7. DESERT. The typical desert is a dry, barren region, generally treeless and sandy. It suffers environmental extremes, with violent and unpredictable weather changes. Its terrain conforms to no particular model. Frequent clear days offer unequaled visibility and flight conditions, but a sudden sandstorm immediately halts all operations. Successful desert operations require special training, acclimatization, and great self discipline. a. Communications. In desert operations, the radio offers the best way to communicate. The low, rolling terrain allows good radio range. Due to the increased distances involved in military desert operations, FM radio communications may prove inadequate, especially in the higher FM frequencies. Rangers, aircraft, and ground crew must all have high frequency radio equipment. Sand or dust in equipment or a poor electrical ground cause most communication problems. Due to the increased distances between land force units engaged in desert operations, helicopters may provide air or ground relay or help deploy ground radio rebroadcast facilities. Table 15-2 shows an example ground-to-air radio transmission. Table 15-2. GROUND TO AIR TRANSMISSIONS Pilot: ALPHA ONE LIMA ONE SIX [A1L16], THIS IS ROMEO TWO BRAVO TWO SEVEN [R2B27], OVER. Ranger: ROMEO TWO BRAVO TWO SEVEN, THIS IS ALPHA ONE LIMA ONE SIX, OVER. Pilot: THIS IS BRAVO TWO SEVEN, CCP INBOUND, OVER. Ranger: THIS IS LIMA ONE SIX, STATE TYPE, NUMBER, AND INTENTIONS, OVER. Pilot: THIS IS BRAVO TWO SEVEN, FOUR UNIFORM HOTEL SIXTIES [UH-60s], TROOP DROP-OFF AND SLING LOAD, FOR YOUR SITE, OVER. Ranger: THIS IS LIMA ONE SIX, ROGER, HEADING THREE TWO FIVE [325], THREE THOUSAND [3,000] METERS. LAND THREE TWO FIVE, SIGNAL ON CALL, LAND ECHELON RIGHT, SLING-LOAD AIRCRAFT USE NUMBER FOUR LANDING POINT, CONTINUE APPROACH FOR VISUAL CONTACT, OVER. b. Navigation. Many of the conditions experienced in cold weather operations resemble those in desert operations. Rangers and pilots find distances and altitudes hard to judge in the desert. The lack of definable terrain features makes navigation difficult, especially at night and over long distances. Also, the sameness of the terrain can influence a pilot to pay less attention to his surroundings. Rangers may have to mark and man release points. c. Landing Sites. The climatic conditions in the desert profoundly affect the setup and operation of landing sites. Most importantly, the Ranger must consider density altitude, wind, and sand (dust). Sand on a landing site can produce brownout conditions similar to those in snowy areas, so the same precautions apply. This makes a rocky area a better landing site than a sandy hollow, depression, or valley. d. Wind. Desert winds generally calm down for an hour or two around sundown. Another calm occurs before sunrise. Other than those times, desert winds can drive dense clouds of dust and sand with hurricane force, and rapid temperature changes often follow strong winds. The Pathfinder leader must consider what times of day the wind will allow him to operate the landing site. (1) The extreme heat often experienced in the desert also affects the aircraft's ACL. When supporting a ground unit, the Ranger leader coordinates with the aviation element to determine the ACL for each type of aircraft. Both the minimum distance between aircraft and the size of the landing point increase in desert operations: 100 meters between aircraft, 100 meter diameter landing points. In daylight hours, ground crew members mark the touchdown points. They paint sandbags a bright color or mark them using some other quick method. Ideally, they use signalmen. 2) When establishing a landing site, the Ranger leader considers taxi procedures. When an aircraft must taxi, the pilot moves it into a vertical position as quickly as possible to reduce the amount of sand (dust) the engine sucks in as well as to avoid a brownout. Pilots should avoid taxiing over the same area repeatedly. e. Liftoffs. Pilots will not try a normal liftoff in a sandstorm. Helicopters with wheels and airplanes should make a running type takeoff. Helicopters with skids should make a maximum performance liftoff.