The Vinh wiretap was an American espionage operation of the Vietnam War. From 7 December 1972 through early May 1973, CIA telephone intercepts of North Vietnamese military communications were supplied to American diplomat Henry Kissinger. As border phone lines were well watched, the decision was made to tap a military multiplex line in the Vietnamese heartland near Vinh. The CIA used a black helicopter to set a clandestine wiretap to eavesdrop on Paris Peace Talks discussions and other intelligence. Background During the Laotian Civil War portion of the Second Indochina War, Central Intelligence Agency spies in the Kingdom of Laos infiltrated the Ho Chi Minh Trail from the west to install wiretaps on Vietnamese communist telephone lines as early as 1966. The North Vietnamese clamped down on that effort with daily patrols checking for tampering along their phone lines on the Trail. By 1971, with Vietnamization winding down American resources in the Vietnam War, the American need for intelligence was greater than ever. The CIA's counter was to target a phone line deep within North Vietnam. Aerial photography disclosed a possible site for a tap 24 kilometers southwest of Vinh. A complex of military phone lines had been installed over a precipitous hill in a remote location; the communist patrols circled that hill without a close inspection of the lines on the summit. However, emplacing a tap at that location would entail crossing the heavily defended Trail and penetrating deep into North Vietnam. Planning and training The CIA had modified two Hughes OH-6 Cayuses into what it dubbed the Hughes 500P, also known as "The Quiet One". Numerous modifications, including a coat of black radar-absorbent paint, produced a stealth aircraft that is still regarded as the quietest helicopter ever. Its first public flight was on 8 April 1971. On 28 April, Air America hired two experienced pilots to train aircrew for the black copter; a third was hired later. They began familiarizing themselves with the craft by flying it about in the Area 51 test range in the US, and other locations. Spring 1972 saw CIA preparations go forward. An attempt was made to train Nationalist Chinese pilots; the CIA wanted the element of deniability in case the aircrew was captured. It was believed an Asian aircrew might be deniable while a Caucasian one would not be. While this was occurring, an air raid specifically approved from the White House