Mk5

USAF Nuclear Weapons Specialist Home Page

Historical Series

"Nuclear Weapons Maintenance in the Early Years- The Mark 5 Bomb"

Finally after Tech School and Unit Training, I was going to be working on live nuclear weapons. It was January 1956 and the place was Alconbury, England. Our Detachment 7 of the 1st Tactical Depot Squadron was attached to the 86th Bomb Squadron of the 47th Bomb Wing. Our contribution to the Cold War effort was to maintain a stockpile of Mk5 Mod 3D nuclear weapons that would be carried by B-45 bombers of the 86th Bomb Squadron.
The fact that nuclear weapons were in England was classified Secret, so when asked what work we did, our answer was "we work on electrical equipment", which was true. Those were the days before the Two Man Policy procedure, the No Lone Zone, Human Reliability Program, the five nuclear weapons safety rules and the Permissive Action Link (PAL).

The term "nuclear weapon" wasn't generally used, instead they were referred to as Special Weapons and the program was the Armed Forces Special Weapons Project (AFSWP). There were no standardized checklists and we didn't have a full time Quality Control person looking over our shoulder. We followed our tech data, the 11N- series tech orders, to the letter. We were very conscious of the importance of our job and took great pride in doing safe and reliable work.
The Detachment staffing consisted of two officers, a clerk typist, a utilities man, a supply man, four 463X0 mechanical bay tech's and four 331X0 electrical bay tech's. We had completed 6 months of unit training at Lowry AFB, Colorado following tech school at Sandia Base, New Mexico and then shipped out to England as a weapons maintenance team.
The Mk5 was a large open pit weapon containing a large amount of high explosives. The front end contained the automatic in-flight insertion mechanism (AIFI), eight MC-300 impact fuses and two Horn Antennae. The fusing and firing set, collectively known as the cartridge, was attached to the HE sphere at the aft end. Two power supply assemblies were attached to the cartridge. The arm/safe switch, also a part of the cartridge, could be monitored and set from an access door in the tail assembly. The ballistic case followed aircraft construction, the aluminum skin was riveted to support rings. The case was in three sections, the front, the center (made up of three panels), and the tail assembly. The weapon was stored and transported on the H-46 trailer.
Maintenance of the weapon consisted of an annual storage inspection, a three month power supply exchange, and inspections following up and down loads on the B-45. Three M-Bay tech's removed the center panels, and then the tail. The cartridge was removed by using the unique H-12 hand truck. The bed of the H-12 could be raised and lowered, tilted left and right, and front and back. The cartridge was taken to E-Bay where it was partially disassembled, tested, and visually inspected. The power supplies were inspected, charged, test discharged, and then charged again. Other tests were run on components of the fuse and fire set. The cartridge assembly test (CAT) was then run and it was ready for return to the M-Bay.

Mk5 bomb at the National Atomic Museum showing open IFI panel.

While E-Bay did their work, the tech's in the M-Bay removed the detonators, visually inspected all components, tested the detonator cables, tested the detonators electrically with the T-27 Detonator Circuit Ohmmeter, performed the pit inspection ,and tested the AIFI. The person doing the pit inspection wore a smock, hood, booties, respirator, and rubber gloves with all the seams taped closed. The floor under the nose of the weapon was covered with paper.

The pit inspection was a visual one using a lighted mirror on a long shaft. The pit was inspected for defects and corrosion. Spalling was a condition where the uranium oxide flakes off and had to be cleaned and removed. This oxide was removed using paper wipes and trichloroethlene. The paper wipes and removed material was checked for radiation using a PAC-1S survey meter. The pit contaminant was alpha particles and relatively harmless outside the body, but once inside could do a lot of damage. After the inspection the person and all his equipment was monitored for alpha contamination. Wipes and contaminants were placed in metal containers and shipped back to the U.S.
After all the weapon visual inspections, testing and paint touch up were done. The detonators were reinstalled and cable routing was checked. The cartridge was installed and then the tail section was reinstalled followed by the three panels of the center section. A final assembly test (FAT) using the T-138 was performed. A Weapons Summary Sheet that contained information such as the timer setting, baro settings, and other pertinent data for the aircrew member (AOB) was completed and placed inside the nose section. The final steps consisted of placing 30 pounds of silica gel inside the tail and 15 pounds in the nose section then taping all the seams with 2 inch wide lead foil tape.
The relative humidity inside the weapon had to be maintaned at or below 40 %. If exceeded, a storage inspection was done. Each weapon had a Weapons Inspection Record, where appropriate entries were made as to what was done, dated, and signed. Also, a Special Weapons Inspection Report (SWIR) was completed and copies were sent to Air Force and Atomic Energy Commission agencies.

Bare metal surfaces were feathered with emery paper and then primed
with zinc chromate followed by a topcoat of olive drab lacquer. The topcoat was applied with a brush and didn't leave a nice smooth coating that matched the factory finish. At the time we were not authorized an air compressor or spray gun so to do a better job we got these large fly spray guns and used them to get a nice finish. There were good for touch up but their ilfe was limited as they clogged and the thinner we then used to clean them damaged the seal. We went through a few cases of the sprayers before we were finally authorized spraying equipment. Aerosol spray cans came into use a year or two later and were great for touch up and stenciling.
Weapons designers gave names to some of the components used in the Mk5 and other open pit weapons. The pits were the Viper or the Cobra, and the initiator was the Urchin. Spies gave three pieces of design information used in the Mk5 and other weapon types to the Russians in the early days of weapons development. One was the design of the HE sphere, the other was how the initiator was made and the other was the formula for the high explosive..
When the 86th Bomb Squadron had alerts, and they had plenty, our job was to make a beeline to the storage area, get a weapons carrier and head for the storage igloos. Another group would be there pushing the weapons out and hooking them to the tow vehicle. There was one

H-72 lifting tool used to remove capsule from birdcage.

person per vehicle, and each got a 45 automatic with a chest holster and a large cardboard map that showed where the weapon was to go. Each of us drove to the flight line as soon as we were hooked up; there was no convoy or escort. Load crews were at the plane and were pulling the tails down so the weapon could be pushed under the bomb bay. After the weapon was positioned the plane would be lowered and the loading was finished. It was quite a sight to be there at night, blue taxi lights, a lot of activity, planes being pulled down by airmen using straps thrown over the tail gunner's compartment, other planes being let back down. Load crews, mechanics, aircrews, and supervisor's all going about their jobs quickly to get the planes airborne as soon as possible. It was a very good feeling to be contributing to the 86th Bomb Squadron's mission.

The above experiences occured from 1956 through 1959 and they are presented here based on my memory of the times and events. Some information may not be accurate and there are some omissions, some deliberate and others due to the passing of forty-six year's. All comments, questions, and additional information are welcome.

A young Airman Wines (right) with co-workers in 1955. Note the one piece overalls, dress uniform with Ike jacket, and Glenn wearing the early AF fatigues.