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dramatically. The Xe Pon River split the area and was roughly paralleled by Highway Nine. Vegetation was mostly single or double canopy jungle along the river. Just south of the river rose a sheer escarpment leading to rugged mountainous terrain. Natural clearings were rare throughout the area and landing zones usually had to be carved out of the dense undergrowth. Intelligence indicated that the natural landing zones would be heavily defended.
The airmobile operations of LAMSON 719 were spread through three areas: the coastal base camps where most of the helicopters were kept at night; the forward staging area at Khe Sanh, where only a few helicopters remained overnight; and the operational area over Laos. Weather conditions at any one or all three locations could have a major effect on helicopter support. The right combination of weather conditions had to exist before helicopters could take off from the coastal bases, land at Khe Sanh to refuel and be briefed for missions, and fly into the operational area over Laos.
Early morning fog, rain and cloud cover, sometimes delayed airmobile operations until late morning or early afternoon. Rarely did weather conditions preclude operations all day throughout the operational area. On occasion, airmobile operations were conducted under ceilings and weather conditions that precluded employment of tactical air support. The smoke and dust raised by artillery combined with natural haze sharply reduced the visibility and frequently caused flying safety hazards. The highest degree of professionalism was required from all pilots.
The terrain features in the area, especially the higher elevation of the Annamite Mountain chain in the operational area, combined with the marginal weather to have a decided effect on airmobile operations. The river valleys, in particular the east-west oriented Xe Pon, became natural flight routes due to navigational requirements in marginal weather. This in turn focused enemy antiaircraft fire on obvious air routes.
The enemy forces in southern Laos were logistics organizations of Base Area 604, with reinforcements from regular North Vietnamese Army units. Besides the permanent service force of engineers, transportation, and antiaircraft troops, the North Vietnam Army forces included elements of five divisions, twelve infantry regiments, a tank regiment, an artillery regiment, and nineteen antiaircraft battalions. Each of the divisions had previously fought in South Vietnam and most of the enemy had taken part in the large-scale operations around Khe Sanh and Hue in 1967 and 1968. In summary, the enemy consisted of large conventional forces of