Some sources describe the bomb as a functional nuclear weapon, but others refer to it as disabled. If it had a
plutonium nuclear core installed, it was a fully functional weapon. If it had a dummy core installed, it was incapable of generating a nuclear blast but could still produce a conventional explosion. in length, the Mark 15 bomb that was lost weighs , bears the serial number 47782, and contains of conventional high explosives and highly enriched
uranium. The Air Force maintains that its "
nuclear capsule" (
physics package), used to initiate the nuclear reaction, was removed before its flight aboard the B-47. As noted in the
Atomic Energy Commission "Form AL-569 Temporary Custodian Receipt (for maneuvers)", signed by the aircraft commander, the bomb contained a simulated cap made of
lead. However, according to 1966 congressional testimony by Assistant Secretary of Defense W.J. Howard, the Tybee Island bomb was a "complete weapon, a bomb with a nuclear capsule" and one of two weapons lost that contained a plutonium trigger. Nevertheless, a study of the
Strategic Air Command documents indicates that Alert Force test flights in February 1958 with the older Mark 15 payloads were not authorized to fly with nuclear capsules on board. Such approval would not come until safer "sealed-pit nuclear capsule" weapons began to be deployed in June 1958. == Recovery efforts ==