On Jan. 21, 1968, a nuclear-armed BUFF engaged on a Chrome Dome flight crashed just five miles from the USAF airfield in Thule on the western tip of Greenland. Heat from the burning bomber’s wreckage melted the ice on which it had crashed, and both the B-52 and the remains of the bombs plunged to the seabed
During the Cold War, General Thomas S. Power initiated a program whereby B-52s performed airborne alert duty under code names such as Head Start, Chrome Dome, Hard Head, Round Robin, and Operation Giant Lance. Bombers loitered near points outside the Soviet Union to provide rapid first strike or retaliation capability in case of nuclear war.
Operation Chrome Dome lasted from 1959 to 1968 and saw B-52s flying 24-hour missions – and carrying one bomb rack containing four live weapons with other empty or loaded with dumb weapons – crew would operate on one of four sortie profiles. One involved flying the so called northern sector, which was effectively a large box-pattern flown around Canada. The second, western sector involved flying north to Alaska while the southern sector was flown from CONUS (the Continental United States) down over the Atlantic and along the Mediterranean. All three sorties profiles relied heavily on air-to-air refuelling tankers. A fourth, the ‘monitor’ sector, involved B-52s flying within visual range of the Ballistic Missile Early Warning System (BMEWS) site at Thule, on the Danish territory of Greenland to determine whether a communications failure was a result of a nuclear strike or just a burnt-out fuse.
As told by Derek Bower in the article B-52 – the Ultimate Cold War Warrior appeared on Key Publishing special publication B-52 Stratofortress, the dangers inherent in flying such mission profiles were obvious and unfortunately (but, perhaps, predictably given the number of sorties and miles flown in what today seem unsophisticated aircraft) a number of B-52s carrying live weapons were involved in crashes. Unsurprisingly, these attracted a lot of attention and caused extreme embarrassment to the U.S. Government.
One of the most high-profile events became known as the Palomares incident. This occurred on Jan. 17, 1966 and involved 68th Bomb Wing 8-52G serial number 58-0256, call-sign ‘Tea 16’, which was flying from Seymour Johnson AFB, North Carolina, on a southern sector Chrome Dome mission. During an air-to-air refuelling bracket over the Mediterranean, the B-52 collided with the refuelling boom of its KC-135A tanker, serial 61-0273, resulting in a massive fuel leak. Shortly after this the tanker exploded, killing its four-man crew. The B-52 suffered massive structural failure and, after its left wing broke away from the fuselage, it crashed close to the village of Palomares on the southern coast of Spain. Four of its seven crew survived. As the wreckage fell to the ground four Mk 28R1 nuclear weapons separated from the aircraft; three fell near the main wreckage but the fourth went into the sea. Even though they did not detonate, a 490-acre area was contaminated with plutonium from the bombs that hit the ground. Meanwhile, an enormous recovery effort was launched to find the fourth weapon. More than 20 U.S. surface vessels and submersibles and the bomb was located on Apr. 2, 1967 at a depth of 2,900ft (880m). It was eventually recovered intact. Unsurprisingly, perhaps, this incident signalled the end of the southern sector mission.
Just two years later, on Jan. 21, 1968, another nuclear-armed BUFF engaged on a Chrome Dome flight crashed – with almost disastrous results. The `Thule Incident’, as it came to be known, occurred when, following an airborne fire, a 380th Strategic Aerospace Wing B-52G, serial number 58-0188, flying out of Plattsburgh AFB, New York, and flown by a crew from the 528th Bombardment Squadron, crashed just five miles from the USAF airfield in Thule on the western tip of Greenland, killing one of the crew members. The aircraft was carrying four B28FI (fused internally) one-megaton hydrogen bombs and rescue services were exposed to significant levels of radiation – conventional explosives, used to act as a catalyst for the nuclear chain reaction, had detonated and scattered fissionable mate-rial far and wide. Denmark had not been formally notified that U.S. aircraft armed with nuclear weapons were using the base, and this added to the ensuing diplomatic maelstrom. By this time, the introduction of submarine-launched ICBMs had made the Chrome Dome mission far less important in terms of America’s nuclear deterrent, but the U.S. Air Force had successfully resisted efforts to have it terminated. Nevertheless, the number of daily B-52 missions flown had, in 1966, been reduced from 12 to four, one of which maintained the ‘Hard Head’ mission over Thule – and it was an aircraft performing this mission that crashed. Heat from the burning bomber’s wreckage melted the ice on which it had crashed, and both the B-52 and the remains of the bombs plunged to the seabed. A massive operation to recover the weapons operated concurrently with an even larger U.S.-Danish bid to dean up the site and repatriate all contaminated materials to the U.S. Despite those efforts, it seems certain that only three of the weapons were successfully recovered.
Many lessons were learned from the incident. It is possible that had the bomber crashed on Thule Air Base, and a nuclear blast had ensued, a full-scale attack on the Soviet Union have been the result. Because of this and the Palomares incident, and another accident involving a B-52 carrying nuclear weapons near Seymour-Johnson AFB, the governments of Russia and the U.S. established a protocol known as the ‘Agreement on Measures to Reduce the Risk of Nuclear War’ whereby the Washington-Moscow President-to-Premier hot-line would be used to advise of any nuclear incidents that might be misinterpreted.
Another consequence was that Secretary of Defense Robert McNamara immediately ordered the suspension of all Chrome Dome missions, and rules governing the carriage of nuclear weapons over foreign territories were rewritten.
This abrupt end saw all nuclear bombs removed from the B-52s within one day. The USAF was reluctant to terminate the airborne armed alert and replaced it with one whereby B-52s stood fully-armed on runway alert ready to be launched at very short notice. To prevent degradation in crew proficiency and readiness state the actual flight
profiles of the armed bombers were still flown, but without the weapons.
Photo credit: U.S. Air Force
Artwork courtesy of AircraftProfilePrints.com