A Landing Zone or "LZ" is a military term for any area where aircraft land.
In the United States military, a landing zone is the actual point where aircraft land (equivalent to the commonwealth landing point.)
In commonwealth militaries, a landing zone is the cartographic (numeric) zone in which the landing is going to take place (e.g., a valley). The actual landing area is the area in which the landing is going to take place (e.g., the field where the aircraft are to land). The landing point is the actual point on which aircraft are going to land (e.g., a point of the field). Each aircraft has a different landing point.
Landing areas are most commonly marked by colored smoke. The standard procedure is for those at the landing area to "pop smoke" (set off a smoke grenade) and declare this over the radio. The pilot says when smoke is seen and what color the smoke is. Those on the ground then respond with what color the smoke should be. Smoke of a different color can mean the landing area has been discovered and compromised by enemies, and the pilot will usually have the authority to cancel any landing.
Vietnam War
LZs were used to a greater extent in the Vietnam War than in other wars because of the widespread use of helicopters. Helicopters were usually the fastest way around Vietnam, and as such, there needed to be Landing Zones for them to land at. LZs allowed troops to be moved to closer positions near the front. While many LZs were temporary, being little more than a clearing in the jungle or a clearing made using defoliant bombs that cleared everything in a diameter of 150 feet, many others were semi-permanent.
The LZ would be constructed with a barbed wire perimeter with sandbag bunkers installed as defensive positions with interlocking fields of fire. Typically one line company (100 or so soldiers) would remain as perimeter defense and often the mortar company was stationary at this location taking up positions along a portion of the perimeter. The remaining battalion infantry companies would conduct operations in the vicinity of the LZ. All but the most isolated LZs also included at least a battery of three 105 howitzers and a fire support center. Some larger LZs placed in critical locations would include a 155 battery as well.
LZ's operated by the First Cavalry Division, especially in war zone C in 1968 and 1969, were often established for specific operations or to draw out the North Vietnamese Army (NVA)units thought to be operating in that area. When the enemy was decisively engaged, forced to move or determined to be operating elsewhere, the LZ would be abandoned for a new location.
LZ Carolyn was one such LZ. First established as a special forces outpost near Cambodia at Prek Lok in Tay Ninh province it was abandoned and later occupied by mechanized elements of the 1st Infantry Division. LZ Carolyn was situated in a location especially irritating to the NVA. Astride one of the main access routes to Saigon for the NVA and VC, its presence was a constant problem for them. In April of 1969 the 2/8 Cavalry reopened the LZ and began operations in its vicinity. The hornet's nest had been prodded. Incoming rocket and mortar rounds were a night and day occurrence. Skirmishes near the LZ were common. Then on the night of May 6, 1969, an entire regiment (95C) attacked the LZ defended by 300 troops.
The 1st Cav troopers suffered 9 dead and 160 wounded. The 95C regiment of the NVA army suffered hundreds of dead and many more wounded. Six were captured alive. The LZ was abandoned 2 weeks later.
Tactical Landing Zones
Tactical landing zones (abbreviated to TLZ) are landing zones selected on the battlefield for the insertion of troops or supplies. A TLZ can be used for the landing of an aircraft (interms of the Royal Air Force this could be a Hercules carrying supplies or troops or any of their helicopters such as the Merlin, Puma or the Chinook). This would be situated in an area which is safe or easy to defend and troops are carefully trained in the insertion process and defensive circles are common.
