There was a period during the Cold War when tensions were so high that the United States
kept nuclear-armed heavy bombers in the air 24-7. Every hour of the day there were bombers
that were airborne, ready to drop their bombs, under the belief that those bombers would
guarantee a second strike capability, even if a first strike by the Soviet Union had destroyed
all of America's airfields. It was an amazing program carried on by our nation's armed forces,
an astounding feat of logistics. But it did raise a problem, because all of that flight time meant
that accidents would occur, and if an accident occurred then that would necessarily involve
thermonuclear bombs. And it's perhaps a statement on how inured we become to the
existence of nuclear weapons that the nation seems to have forgotten about the five, yes,
five, airplane crashes involving thermonuclear bombs that occurred during the lifetime of the
program that was called, Operation Chrome Dome. It is history that deserves to be remembered.
At the height of the Cold War, leaders sincerely feared their opponent would contemplate nuclear
armageddon. And believed that nuclear war could only be avoided on a credible promise,
that if either side were to launch a first strike, they would inevitably be destroyed themselves
as well. But that status quo was challenged with the advent of nuclear missiles, and what the US
perceived to be a missile gap. For example, in the period 1961 to 1963, national intelligence
estimates were that the Soviet Union had between 200 and 300 intercontinental ballistic missiles,
and seven to 800 intermediate range missiles. That was enough that, intelligence estimated,
the Soviet Union could destroy all the US and allied nuclear retaliatory forces,
even if those forces were on ground alert. To fill the gap, the allies needed to be able to
have their strategic bombers respond more quickly than ground alert allowed. General Thomas S.
Power, the Commander-in-Chief of the United States Strategic Air Command, pioneered the somewhat
radical idea that the air force's new bomber, the B-52, could maintain 24-hour airborne alert duty.
US bombers carrying hydrogen bombs, and all the codes and equipment needed to arm
and deploy those bombs, would be airborne at all times. Loitering at strategic locations
outside soviet airspace, where they could quickly retaliate, or counter any threat.
The idea was radical, it would press the equipment and the personnel in ways that
had never been tested before. The idea of aerial refueling goes back to the 1920s.
The first known in-flight refueling between two planes occurred on june 27th
1923, between two Airco DH.4B bi-planes of the United States Army Air Service. Using this process
DH.4Bs were able to set a number of air endurance records in the early 1920s, and later aircraft
continued to experiment with the process, and set endurance records through the 1930s.
But these systems, despite their obvious potential, were still rudimentary and dangerous,
and none were regularly utilized during the Second World War. You could say that the idea
had truly achieved its potential when, from February 26 to March 3rd of 1949, an American
B-50 Super Fortress long-range heavy bomber named Lucky Lady 2 of the 43rd Bomb Wing, flew non-stop
around the world in 94 hours and one minute. A feat made possible by in-flight refueling.
But in reality, the process for keeping heavy bombers in the air for long periods of time was
already being tested by the Air Force prior to Lucky Lady 2's flight. SAC had been considering
some version of air alert for years, but the technology was not considered to be ready. The
first test of the concept was done in the spring of 1958 under the code name, Operation Curtain
Raiser, using B-36 bombers of the 72nd Bomb Wing, flying from Rambi Air Force Base in Puerto Rico.
Then that winter, the test continued with Operation Head Start using B-52 bombers
of the 40nd Heavy Bomb Wing, first from Loring Air Force Base in Maine, and then from Bergstrom
Air Force Base in Texas. The program required more than improving in-flight fueling techniques, they
included researching maintenance schedules, crew schedules, flight paths and even crew nutrition.
To be sure, the program was controversial within the military, and the government.
General Curtis LeMay who had previously been the Director of the Strategic Air Command,
and from 1957, was Vice Chief of Staff of the United States Air Force, expressed concerns about
cost, flexibility, crew fatigue, the ability to coordinate the plane's attack with other forces,
competition with other air force priorities and the impact on longevity
of the B-52 bombers. Oddly, he did not list among his concerns the fear that there could
be accidents involved with constantly operating heavy bombers carrying thermonuclear weapons.
Certainly one of the most pressing issues of the technology was the in-flight refueling,
which had not, to that point, been used on anything approaching the scale. The Lucky
Lady 2 was refueled using the clumsy looped hose method in a modified B-29. The system depended
upon the tanker using a sort of grappling hook to grab a cable let out by the receiver aircraft.
The Air Force knew at the time the system was too clumsy for regular use. Next the Air Force tested
a probe and drogue system where the tanker uses a flexible hose with a basket that goes over a
probe on the receiver aircraft. While this is a far simpler system than the looped hose method,
and still widely used today, and preferred by the US Navy, the system has a limited flow rate
due to the flexibility of the hose. Instead, the US Air Force preferred a rigid flying boom,
where an extendable boom is maneuvered into a receptacle on the receiving aircraft. But even
with this system the Air Force had a problem with their tanker aircraft. The KB-29 and its
replacement, the KC-97 Strato Freighter, were both developments of the Boeing B-29. As piston-driven
aircraft, they were too slow for jet aircraft causing many problems and risks in refueling.
A B-52 typically had to raise its flaps and lower its landing gear to slow down enough
for aerial refueling. In addition, the piston driven aircraft required a reduction in altitude
to around 16 to 18,000 feet which often put the bombers right in the clouds, and turbulence, as
they were being refueled. In 1957, the Air Force started phasing in the Boeing KC-135 StratoTanker.
Based on the Boeing 707, the KC-135 was the Air Force's first jet-powered refueling tanker.
Finally, the Air Force had a workable system to practically allow airborne alert duty.
Despite continued concerns by the Air Force about costs,
SAC continued to fly fully prepared, nuclear-armed strategic bombers in the air around the clock for
the next decade. The broader program became called Operation Chrome Dome.
Operation Chrome Dome might have as many as a dozen bombers in the air, and ready to strike
at any time of the day or night. A typical Chrome Dome mission, which might be flown by one B-52,
or a group of three, called a Cell, would take off from Fairchild Air Force Base near
Spokane Washington, across the US to the Atlantic Ocean, up to the Arctic Circle,
turn towards Alaska, and then back to Fairchild. The mission would take around 24 hours, and
include two in-flight refuelings. Crews quickly became adept at the system. But Chrome Dome meant
a huge amount of flight hours; over six thousand airborne alert missions had been flown by 1961.
With that much flying things would certainly go wrong. While the program was itself no secret,
General Power had announced the operation publicly as the purpose was deterrence,
the Air Force was characteristically obtuse to the public about the risks. A quotation from
SAC in TIME magazine in 1961 said, “At worst, only the TNT in an unarmed H-bomb explodes on impact.”
The first accident involving nuclear bombs of Operation Chrome Dome came January 24th 1961
over Goldsboro North Carolina. A B-52-G experienced a fuel leak that evolved
into a structural problem causing the crew to lose control of the aircraft.
Five of the crew bailed out safely, three died. One of the two nuclear bombs on board
was recovered, and another buried itself so deeply in a field that it could not be recovered.
The Air Force bought an easement on the land, and much of the bomb is still buried there today.
Neither of the bombs high explosive components had exploded, and no radiation was released.
But the bombs had progressed through much of their arming sequences, moving them dangerously close to
a nuclear detonation. Experts still disagree as to the extent of that possibility. Flaws were found
in the design of the wet wing of the B-52 designed to hold fuel, and the areas susceptible to fatigue
were modified to improve stability. Two months later in March, a series of mechanical failures
and crew mistakes caused a B-52F to run out of fuel near Yuba City California. The crew all
managed to eject from the plane safely, and the plane crashed into a clear flat barley field. The
onboard nuclear weapons were released but their safety interlocks held, and there was no explosion
or release of radiation. A third crash during Operation Chrome Dome occurred in January 1964,
when the stabilizer of a B-52B broke off in rough weather. The plane crashed in rough
territory near Savage Mountain Maryland. One crew member was unable to eject, and two more froze to
death after bailing out of the plane. The nuclear bombs however were recovered relatively intact.
Three accidents was not a surprise given the large amount of flight time involved
in Operation Chrome Dome, but none of those three accidents instead resulted
in any radiation loss, or even the explosion of the high explosives
on the nuclear warheads. But that luck would run out on January 17th 1966.
A B-52G flying from Seymour Johnson Air Force Base in North Carolina was flying
the southern route of Operation Chrome Dome, which took it across the Atlantic over Spain,
and into the Mediterranean, before returning home by Gibraltar. During the second refueling,
off the coast of Spain, the B-52 came in too fast. The boom operator did not, reportedly,
call for the B-52 to break away. The B-52 struck the boom. The collision severed the
left wing of the B-52 causing a fuel explosion that destroyed the KC-135,
killing all four crew members aboard. Two members of the B-52 crew were located near the point of
the collision, and were not able to eject. A third ejected, but his chute did not open.
The B-52 radar navigator suffered severe burns, but landed safely, and was taken to the hospital.
Three other crew members safely ejected, but they landed in the ocean where they were rescued
by fishermen. On board the disintegrating aircraft were four Mark 28 hydrogen bombs.
Three fell to the earth near the Spanish village of Palomares, the fourth fell into the ocean.
One of the three landed via parachute and was intact, but the conventional explosives on the
other two exploded on impact, causing radioactive contamination across some 2.6 square miles of
farmland, woods, and residential areas. Dispersing some seven pounds of plutonium-239, a dangerous
and toxic carcinogen. Air Force personnel were rushed from US Air Force bases across Spain to
aid in the cleanup. The US and Spain dug up 6,000 barrels of contaminated soil, and shipped it back
to the United States. The Air Force called for the assistance of the Navy to recover the fourth bomb.
Nearly 30 navy vessels were involved in the search, which took more than two months,
despite having a witness who saw the bomb hit the water. The bomb was eventually recovered using
some of the highest technology recovery vehicles in the navy. The submarine recovery ship USS
Petrel, the deep submergent vehicle Alvin, and the Cable-Controlled Undersea Recovery Vehicle CURV-1.
After the accident Spain forbade the US Air Force from overflying Spanish territory with
aircraft carrying nuclear weapons, and other countries issued complaints as well. Operation
Chrome Dome was ended two years later in 1968 when a fifth accident occurred,
this one also releasing radioactive material, this time in Greenland. Despite the cleanup,
more radioactive material was found near Palomares in 2006, and then at another site in 2008,
and the United States and Spain have entered into another agreement to do further monitoring,
and clean up at the site. Both governments claim that they found no ill health effects
for the people of Palomares as a result of the incident, but other experts argue
that the site has been poorly monitored, and that the health effects are still unknown.
The empty casings of two of the bombs involved in this incident are now on display in the
National Museum of Nuclear Science and History in Albuquerque New Mexico. Air Force personnel who
are involved in the cleanup, now claim a number of lingering health effects that they claim came from
inadequate safety procedures. The Air Force has denied any such links, and secrecy surrounding the
event has made it difficult for the personnel who have been so affected to claim benefits.
In the end, it's not a surprise that Operation Chrome Dome resulted in accidents. It was a very
ambitious program that kept nuclear-armed bombers in the air, around the clock,
for a decade. It was almost certainly going to lead to some accidents. But in fairness to the
program, we cannot know the effect that it had on nuclear deterrence during the tensest periods
of the Cold War. Operation Chrome Dome might well have prevented nuclear armageddon. Still,
the five accidents of Operation Chrome Dome remind us that no system is perfect,
and that is important to know in the Nuclear Age. It is history that deserves to be remembered.
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