Archive for September, 2012

Trouble at Mars Bluff

September 18, 2012


Tales from the Nuclear Age

Copyright © 2012 by Charles Glassmire


Sept. 17, 2012

 Trouble at Mars Bluff

            On March 11, 1958, the rural community of Mars Bluff South Carolina was a sleepy little suburb some six miles outside of the city of Florence. At about 3 p.m. one of its citizens, Walter Gregg, was with his son (Walter Gregg Junior) making benches in a work shed near his house. 37 year-old Walter was a railroad conductor with the Atlantic Coast Line Railroad and an ex paratrooper from World War II. He had built the house himself with special care and high quality materials, and the family had moved in five years earlier. His wife, Ethelmae, (Effie) was busy inside the house. They had met on a blind date and married in 1942.

          Walter had constructed a play house in the backyard for his two girls, Helen age six, and Frances age nine, who were playing there with their cousin Ella Davies, also age nine.  Their games soon led them out of the playhouse onto the grass to a location about 200 yards away, when they looked up to notice the loud sound of a high flying jet aircraft approaching …(1)


           Early that same morning, at 0800 hours, at Hunter Air Force Base near Savannah Georgia, aircraft number 53-1876A was being readied for a mission. She was a six-engine B-47 Stratojet, one of the Air Force’s newest and hottest nuclear bombers, and she was being prepped for a long range Special Weapons mission under Operation Snow Flurry. The operation was to be a high altitude mission across the Atlantic for four Stratojets of the 375th Bombardment Squadron of the Strategic Air Command.

          The objective was to carry a nuclear weapon to Bruntingthorpe Air Base England, aerial refuel enroute and then, before landing, conduct a simulated weapons drop onto an electronic target in Great Britain. Briefings by two generals on this mission had begun some ten days earlier and tension was building. The operation would be scored, points awarded and the timing for the mission was a critical measure of aircrew performance.

          But there was a problem. The “Special Weapon” involved was known as a Mark 6 Nuclear Weapon – an “Atomic Bomb” to the layman. Measuring 5 feet in diameter and 10.6 feet in length, the weapon weighed almost 4 tons, and could produce a nuclear detonation of magnitude about 30 kilotons (about double the size of the Hiroshima bomb). She was filled with a special high explosive designed to compress the Plutonium core into a tiny sphere capable of generating a chain reaction and releasing enormous amounts of energy in the process.

          The Plutonium core for the weapon (called the “pit”) was surrounded by a Uranium tamper. It had been delivered by an officer representing the Atomic Energy Commission early that morning (at this point in time all nuclear materials were still owned by the AEC, and “loaned” to the military for special operations). The pilot, Captain Earl Koehler, signed for the pit, certifying he wouldn’t use it for non-military purposes. The pit was not inserted into the bomb, but was stored in the aircraft separately in a special container known as the “Birdcage”. The pit could be inserted at any time during the flight, arming the weapon to create a nuclear explosion. Without the pit, only the thousands of pounds of TNT-like explosive could detonate in a conventional chemical explosion.

          There were two systems to secure the weapon inside the aircraft bomb bay. A pneumatic device which could be locked remotely from the co-pilot position, and a simple steel locking pin which could be manually inserted into position. When the pin was placed it was impossible for the bomb to leave the aircraft. By Air Force regulation, the pin had to be removed on takeoff and landing so that, in an emergency, the weapon could be jettisoned, allowing better control of the aircraft. It was then to be locked again after takeoff for the duration of the flight.

          The problems began after the aircrew arrived early that morning. The aircraft crew consisted of Capt. Koehler Aircraft Commander, Capt. Charles Woodruff Co-Pilot and Nav/Bombadier Capt. Bruce Kulka. A special two man loading crew was unable to engage the locking pin to secure the weapon in the bomb bay, thus guaranteeing safe handling before takeoff, which was scheduled for late afternoon. A special weapons supervisor was summoned. After suspending the weapon in a shackle mechanism, he utilized all his high technology skills and special training, secured a hammer and proceeded to pound the pin into its locked position! Since all pre-flight checks had to be completed by 10:30, neither crew ran the engage/disengage cycle to test the locking mechanism.

           After briefings for weather and operations, engine start was at 3:42 p.m. Nine minutes later while 1876A taxied into takeoff position, Co-pilot Woodruff pulled the pneumatic lever at his station behind the pilot and dis-engaged the locking pin. The weapon now could be jettisoned freely in event of emergency. Wheels up was at 3:53 and the bomber began the climb to 15,000 feet to join her three sister ships. Passing through 5,000 feet, Woodruff pulled the lever to re-engage the locking pin to secure the weapon in the bomb bay. Nothing happened, except a red light began blinking on the pilot’s console. Negative Function! For another 5 minutes Woodruff worked the locking mechanism to no avail. The Nuclear bomb was not secured and the crew now had a serious problem!(1)

          The Aircraft Commander now told Navigator Kulka to leave his position in the nose of the plane, go into the bomb bay and try to seat the pin by hand! This required the crew section to be depressurized and all to go on oxygen. It also meant Kulka had to remove his parachute, since the small crawl tube leading to the bomb was not large enough to allow a bulky parachute. So now, dragging an oxygen bottle hosed to his mask, Kulka crawled to the bomb bay and began searching for the locking pin.

          After 12 minutes of frantic searching, all realized no one knew the actual location of the locking device. Kulka, being a short individual, then deduced (correctly) the pin was invisible above the top of the bomb curvature, and he began jumping up to try to see over the top of the weapon. Inadvertently, his hand took hold of the handle for emergency bomb release, and his next jump released the weapon. A four ton nuclear bomb fell onto the bomb bay doors, dragging Kulka down with it. After a few seconds the bomb bay doors gave way and the bomb fell free of the aircraft into the airspace over South Carolina …

 (To be continued)


(1)  “Aircraft 53-1876A Has Lost a Device”, by Clark Rumrill, American Heritage Magazine, Vol. 51 Issue 5, Sept. 2000.

(2)  “The Day a nuclear bomb fell on South Carolina…”, by Anthony Bond, 26 April 2012,, photos courtesy of the Columbia Star Newspaper.

(3)  ”Man Recalls Day a Nuclear Bomb Fell On His Yard”, by David Klepper, The Sun News – SC, 11-24-3,

(4)  “Mars Bluff, South Carolina”, Wickipedia.

(5)  ”Mars Bluff “Broken Arrow”, August 08,

(6)  “Atom Bomb Dropped Here”,

(7)  “Mars Bluff Bomb”,

(8)  “March 11,1958: An Atom Bomb fell on Mars Bluff,SC, by Tom Horton,