U.S. Air Force deploys WC-135 nuclear sniffer aircraft to UK as spike of radioactive Iodine levels is detected in Europe

EIELSON AIR FORCE BASE, Alaska -- Personnel from the 55th Aerospace Medicine Squadron and 55th Aircraft Maintenance Squadron report a "thumbs down," which indicates the WC-135 Constant Phoenix aircraft is above acceptable levels of contamination and needs be parked in an isolated location to be decontaminated. This initial radiation survey was done every time the WC-135 landed after collecting air samples in international airspace over the Pacific as part of Operation Tomodachi. (Air Force photo by Staff Sgt. Christopher Boitz)

The USAF WC-135C Constant Phoenix might be investigating a spike in radioactive levels in Norway. Someone speculates the release of this radionuclide could be the effect of a Russian nuclear test.

On Feb. 17, 2017, U.S. Air Force WC-135C Constant Phoenix Nuclear explosion “sniffer,” serial number 62-3582, using radio callsign “Cobra 55” deployed to RAF Mildenhall, UK.

As we have already reported the WC-135 is a derivative of the Boeing C-135 transport and support plane. Two of these aircraft are in service today out of the ten examples operated since 1963. The aircraft are flown by flight crews from the 45th Reconnaissance Squadron from Offutt Air Force Base while mission crews are staffed by Detachment 1 from the Air Force Technical Applications Center.

The WC-135, known as the “sniffer” or “weather bird” by its crews, can carry up to 33 personnel. However, crew compliments are kept to a minimum during mission flights in order to lessen levels of radioactive exposure.

Effluent gasses are gathered by two scoops on the sides of the fuselage, which in turn trap fallout particles on filters. The mission crews have the ability to analyze the fallout residue in real-time, helping to confirm the presence of nuclear fallout and possibly determine the characteristics of the warhead involved.

Along with monitoring nuke testing, the WC-135 is used to track radioactive activity as happened after the Chernobyl nuclear plant disaster in the Soviet Union in 1986 and Fukushima incident back in 2011.

One of these aircraft was deployed near North Korea in anticipation of Kim Jong Un rocket launches then was spotted transiting the UK airspace in August 2013 raising speculations it was used in Syria thanks to the ability to detect chemical substances down wind from the attack area days, or weeks after they were dispersed.

Although they cross the European airspace every now and then, their deployment in the Old Continent is somehow rare. As of yet, there has been no official statement from the U.S. military about the reasons why such nuclear research aircraft was deployed there. However, many sources suggest the aircraft was tasked with investigating the spike in Iodine levels detected in northern Europe since the beginning of January.

Iodine-131 (131I), a radionuclide of anthropogenic origin, has recently been detected in tiny amounts in the ground-level atmosphere in Europe. The preliminary report states it was first found during week 2 of January 2017 in northern Norway. Iodine-131 was also detected in Finland, Poland, Czech Republic, Germany, France and Spain, until the end of January.

However, no one seems to know the reason behind the released Iodine-131. Along with nuclear power plants, the isotope is also widely used in medicine and its presence in the air could be the effect of several different incidents.

Or, as someone speculates, it could have been the side effect of a test of a new nuclear warhead in Russia: an unlikely (considered the ability to detect nuke tests through satellites and seismic detectors) violation of Nuclear Test Ban Treaty.

Maybe the WC-135 will help authorities find out the origin of the Iodine-131.



About David Cenciotti
David Cenciotti is a journalist based in Rome, Italy. He is the Founder and Editor of “The Aviationist”, one of the world’s most famous and read military aviation blogs. Since 1996, he has written for major worldwide magazines, including Air Forces Monthly, Combat Aircraft, and many others, covering aviation, defense, war, industry, intelligence, crime and cyberwar. He has reported from the U.S., Europe, Australia and Syria, and flown several combat planes with different air forces. He is a former 2nd Lt. of the Italian Air Force, a private pilot and a graduate in Computer Engineering. He has written five books and contributed to many more ones.


  1. Nice to see some general read the story in the local news paper and then decided to act decisively.. Trillions spent on defense and this is the best we get.. How 9-11 happened we may never know.. Or will we?

  2. This makes me wonder if the aging Russian nuclear submarine fleet had another catastrophic event.

  3. Would be interesting to see historical readings for comparison but these are perhaps classified. Adding to the conspiracy theories, maybe someone was just transporting uranium?

    • Yes, much of the records of detection of foreign tests and most high yield US tests in the Pacific remain classified. Tracks and some data from testing in Nevada were long ago declassified. The Centers for Disease Control and the National Cancer Institute have done preliminary estimates of the extent of the harms associated with atmospheric testing, but require the more detailed historical data the Air Force continues to hold in order to provide a more accurate assessment of atmospheric testing’s health and environmental effects.

      Beyond the current operations possibly being a training deployment taking advantage of an opportunity to target the detected anomalies (remember that volcanic and other natural activities can also generate suspicious signatures that require investigation), there’s a rather significant possibility that could be associated with the DPRK or another actor that hasn’t been mentioned.

      After fuel rods of uranium have been irradiated long enough to efficiently produce Pu-239 in plutonium production reactors, they were typically cooled for some time to allow the I-131 and other isotopes contained within them to decay to more manageable levels. However, if sufficient space and suitable equipment is available, the rods can be processed while still “green,” but this releases a lot of radiation that would otherwise have decayed. Besides considerable discussion in the dissertation I cited in my earlier post, you can Google “GREEN RUN” for more info.

      The GREEN RUN took place at Hanford shortly after AFOAT-1’s detection of the first Soviet test in late 1949. It was apparently undertaken to calibrate detection apparatus and to provide a chance to gauge the ability to distinguish between a test event and a reactor accident. While it also included sampling for krypton-85, the GREEN RUN was notable for releasing far more radiation than originally anticipated, then having that linger much longer locally that night due to unanticipated weather conditions, leading to much higher ground level doses than originally calculated to areas around Hanford.

      Beyond detection of nuclear testing on a global basis, AFOAT-1/AFTAC’s mission also includes assessing fissile material production, it’s possible that is what the CONSTANT PHOENIX missions were targeting, rather than a nuclear test. If the DPRK suddenly quit allowing its fuel rods to cool before processing, instead beginning the process almost immediately, it could provide a temporary acceleration in fissile material production and thus warhead production, something its often erratic leadership might find useful under the circumstances.

  4. Poland has begun making plutonium. They need their own nuclear weapons to deter Russia since they can’t completely trust NATO.

  5. “crew compliments”

    I rather doubt that the number of people in the crew is limited in order to keep too many favorable comments about the flight from being made. However, I can see where the crew complement (i.e., the number and qualifications of the people in the crew) would be kept to the minimum necessary to ensure that as few people as possible are exposed to radiation.

    Spell check has its limitations, one of which is that it does not eliminate homonyms.

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