 In phases of any military operations in an unconventional warfare operational area or UWOA, it may be necessary to airdrop personnel and supplies. But as operations expand and the guerrilla forces control most terrain and recruit more partisan fighters, it becomes necessary to find new ways of resupply and ways of exfiltrating people, including key resistance leaders whose lives are endangered by the expanding operations and whose usefulness can be increased by having them where they can help formulate future plans. The skyhook method could be used to exfiltrate these men. Even water exfiltration by submarine could be possible. But in this case, the detachment commander feels that it would be more practical to use aircraft. Damaged landing zones or LZs on file at the SFOB have been checked during preliminary reconnaissance. One has been confirmed as the LZ for the proposed exfiltration. The same general considerations applicable to DZ selection apply to the selection of LZs. However, size, approach features, and security are different. LZs should be located in flat or rolling terrain and for security purposes as far away from enemy action as possible, also away from the guerrilla base to avoid the possibility of compromising the base. In landing zone operations, detection by the enemy is easier than in drop zone operations since the selected site assumes the characteristics of a landing field after preparation and clearing. The surface must be level and free of obstructions such as ditches, deep ruts, logs, fences, hedges, shrubbery, or grass over 18 inches high. The subsoil must be firm to a depth of two feet, otherwise it will not support the aircraft. An improvised technique for checking subsoil firmness is to carry a man piggyback the length and width of the LZ. If the carrier sinks deeper than the thickness of the soles of his shoes, the ground may be considered too soft. Loose gravel or sand is acceptable over a firm subsoil, and the surface gradient must not exceed 2%. For day operations of light aircraft, the LZ size should be 1,000 feet long, with a 10% safety factor added to each end, and 50 feet wide. For light aircraft night operations, the runway is widened to 75 feet for additional safety. Medium aircraft require a longer runway, 2,500 feet, plus 10% for safety zones added at each end, and a landing width of 60 feet. For night landings, the width is increased to 80 feet. To allow for wing clearance, all runways for light or medium aircraft should have 25 foot strips along both sides of the runway cleared to within 3 feet of the ground. Since aircraft must land into the wind, the runway should be laid out to face the prevailing winds. For one approach landing zones, a sufficiently cleared area must exist to permit a level 180 degrees turn to either side of the landing zone, within a radius of two nautical miles for medium aircraft, like the C-123, or one nautical mile for light aircraft, and special light aircraft like the U-10. Also to be considered are the approach and takeoff clearances. These are based on the climb and glide characteristics of the aircraft. For light aircraft, the ratio is 1 to 20, one foot of gain or loss of altitude, for every 20 feet of horizontal distance traveled. Since our present missions will mostly concern resupply of the partisan forces, we are interested in medium aircraft characteristics. The climb-glide ratio for this type of aircraft is 1 to 40. All heights of obstacles are computed from the level of the landing zone, distances are computed from the nearest end of the landing zone, approach clearances from the approach end of the zone, and takeoff clearances from the takeoff end. Based on the climb-glide ratio for medium aircraft of 1 to 40, no obstruction higher than 6 feet, and closer than 240 feet is permitted. A 50-foot obstruction may not be closer than 2,000 feet, and a 500-foot obstruction may not be closer than 4 nautical miles. Hills of 1,000 feet or more may not be closer than 8 nautical miles. Having determined that the selected LZ is best for their purpose, the commander will send the required information to the Special Forces Operational Base. The SFOB will need to know the LZ codename, location, description, open quadrant, obstacles, reference points, date-time group, exfiltration required, and alternate LZ. While awaiting confirmation from the SFOB, the commander briefs the command and marking parties in placement of markers. The pattern outlining the limits of the runway consists of seven marker stations. The runway is 2,500 feet in length. The downwind end of the LZ is marked by stations A and B, which are positioned so as to allow the 10% safety factor. These stations also represent the initial point at which the aircraft should touch the ground. 1,000 feet up the runway is station C, the last point at which the aircraft can touch down and complete a safe landing. Station D is 500 feet farther up. Station E, another 500 feet. And station F, another 500 feet. Stations F and G indicate the end of the runway. Note that the station C, D, E, and F markers are on the pilot's left as he approaches the runway. Because this will be a night operation, lights will be used instead of marker panels. The RCL, or reception committee leader, is located at a position approximately 50 feet to the left of station B. The RCL will handle the signal light. This color will contrast to those used in the LZ pattern for recognition and authentication and to indicate the approach end of the LZ. During daylight operations, a smoke grenade or marking panel of contrasting color would be used as the recognition and authentication signal. The SFOB, having received the LZ request of the detachment commander, has completed coordination with the Air Force. The Air Force has the responsibility of flying the mission. Before they must check the information and, if necessary, modify it according to their tactical operational requirements. This revised data will be passed on to the SFOB, which will transmit a confirmation message to the detachment. With the landing confirmed, the commander then makes final preparations to receive the aircraft. The RCL, the marking party, and the exfiltrators arrive at the LZ, which the surveillance teams and advanced security forces have already checked for enemy activity. As planned, the RCL, the special forces representative, and people to be exfiltrated, position themselves in a designated area in the vicinity of station B. This is the point at which the plane will stop to unload and load. Marker stations are established by the RCL to provide for proper distance and alignment. It's almost impossible to hide from the enemy. Not only do they have patrols who can report our activities, but they also possess highly sophisticated tracking equipment. At enemy headquarters, a look at the map indicates the enemy knows the track of the aircraft. He is also aware that once it is out of his area of influence, he will have difficulty continuing the track. Since he is unaware this is a landing operation, he tries to cover the possible drop zones that might be used. Two minutes until landing time. Time to light the markers. The markers will remain lit for a period of four minutes or until the aircraft completes its landing. Final recognition signal is given by the RCL using a signal light. The pilot recognizing the correct signal enters his final approach. For purposes of illustration, this diagram represents a landing zone in which flashlights are used by the marking party for receiving an aircraft. After the aircraft passes the RCL position, it will touch down prior to reaching marker station C. As the plane passes each marker station, each marker station extinguishes its light, except A and B, which have reversed their lights to shine in the direction of the taxiing aircraft. The RCL, who has taken up a new position between stations A and B, shines his light on the nose of the approaching aircraft and guides it around to park in takeoff position. As soon as the aircraft is in park position, persons to be exfiltrated are quickly loaded aboard. The RCL, located forward and to the left of the pilot, causes the LZ lights to be illuminated. He then signals the aircraft to take off. As the aircraft passes each marker station, the light is extinguished. The UWOA becomes secure. Daytime landing zone operations are planned. Replacements load aboard a C-47, the medium aircraft assigned to this mission. Wounded to be evacuated are moved to the vicinity of marker station B. Daytime recognition may be accomplished by a smoke grenade, placed 50 feet to the left of station B. During daylandings, marker panels replace lights. Markers can be of any color that contrasts with the terrain and are clearly visible from the air. They are held facing the approach path. Replacements unload and wounded men are sent back for treatment. Link up with other units is imminent. In conjunction with link up operations, it is deemed advisable that instead of infiltrating a liaison detachment, key personnel will be exfiltrated from the operational area to liaison with the main force and discuss support requirements during link up. The nearest LZ is a river, and in this situation where a minimum of personnel are involved, a light aircraft can be used. Water LZs for light aircraft night landings require a length of 1,500 feet, plus 10% safety zones at both ends. For night landings, the minimum required LZ width is 300 feet, plus a 150-foot safe taxi area. Day landing minimum LZ width is 125 feet, plus a 100-foot safe taxi area. The minimum water depth is 30 inches. The entire landing zone must be free of any obstructions within the minimum water depth. Wind waves must not exceed 3 feet. Surface swells should not exceed 1 foot in height. And wind velocity must not exceed 20 knots. Cross wind speeds should not exceed 10 knots. The normal method for marking light aircraft water LZs is to use four marker stations. Station A is positioned at the downwind end of the strip and indicates the touchdown point. Station B, which is also the RCL position, is 500 feet from station A. This indicates the last point at which the aircraft can touch down and complete a safe landing. Station C marks the upwind end of the LZ. The D marker station is included at the approach end of the landing zone to indicate landing zone width. The authentication signal from the RCL is given from station B. At night it's a contrasting colored light. During the day it may be a smoke grenade. A security party moves out ahead of the reception committee. These men will position themselves to command all land approaches to the LZ and make sure that enemy ground forces do not interfere with the landing operation. Once the area has been checked by the security forces, the reception committee moves out to set up the LZ. With them is the one man to be exfiltrated. As four boats, one for each marker station and the RCL move out, they check the LZ for floating debris that might interfere with the landing. After receiving the authentication signal from the RCL, the pilot initiates a final approach. The aircraft taxis to the right around the RCL boat until it is abreast of it, at which time the boat cruise secures the aircraft pontoon. Marker lights are extinguished as the aircraft takes off. An excellent means of moving supplies and men is the helicopter. This type of aircraft requires its own LZ, entirely different than those for fixed wing aircraft. For day landings, a helicopter can land in a space slightly larger than its landing gear and with enough side clearance for its rotors. Should it have to land at night, the LZ must be larger. The helicopter night LZ is 300 feet in diameter. The center landing area is 170 feet in diameter and must be cleared to the ground of all obstructions and must be firm enough to support the weight of the helicopter. Surrounding the landing area is an area 65 feet wide, cleared to within three feet of the ground. Maximum ground slope is 15 percent. LZs for rotary wing aircraft are marked to provide identification of the reception committee to indicate wind direction and to show touchdown area. Five lights or markers positioned at A, B, C, D and E form a Y. Stations C, D and E outline the touchdown area. Identification signals are given from A where the RCL is positioned. The stem of the Y indicates wind direction. The arrow represents the approach path of the aircraft. Although in some cases the rotary wing aircraft can ascend and descend almost vertically, for planning purposes a climb glide ratio of 1 to 5 exists. For best results, rotary wing aircraft land upwind similar to fixed wing aircraft. They will need an approach path about 250 feet wide. The first helicopters will touch down in two hours. Meanwhile, any critically wounded are prepared for evacuation. To set up the Y signal pattern, the direction of the wind is determined. The pilot recognizes the correct authentication signal. Had the signal been incorrect or the markers not placed properly, the pilot would have aborted the mission or moved to an alternate LZ. As has been demonstrated, it is practical to land aircraft of various types in almost any seemingly inaccessible place. And where aircraft cannot land, supplies and personnel can be air-dropped. With today's practical experience and modern technology, there is no place in the world that cannot be reached and supplied by special forces air operations.