An ongoing air campaign by the United States seeking to destroy the Trail had little perceptible effect on the Communist resupply effort.

[1] The Central Intelligence Agency (CIA) backed a number of guerrilla intrusions onto the Trail in an attempt to cut supplies going into South Vietnam.

The huge Operation Lam Son 719 attack of February 1971 proved insufficient to sever the supply conduit of the Trail.

With truce talks in progress, the military emphasis was on a land grab to gain territory before a ceasefire ended the secret war.

[6] On the night of 18 October 1972, a Royalist Commando Raiders team made a low level parachute drop from an Air America Twin Otter to secure a landing zone near Salavan.

The following morning, the 21st Special Operations Squadron (21st SOS) began helilifting Groupement Mobile 42 (GM 42) into rice paddies adjoining the Salavan airstrip on its westward side.

[7] While ferrying in troops in the third lift, an Air America H-34 was shot down in flames, killing a CIA adviser and his operational assistant.

[9] The Royalist response was to helicopter in Groupement Mobile 43 (GM 43) to capture the Tha Theng supply point supporting the 9th Regiment.