The thing that makes the least sense to me is that the other safety mechanisms "failed". I wonder exactly what that means. Usually, as far as I know, bombs do not do anything if they somehow become detached from the aircraft without being armed first. There should have been no parachute deployment and no arming sequence (i.e., no checking barometric or radar altitude for a valid drop) The article says something like "when the bomb hit the ground, a firing signal was sent" - this sounds very garbled to me. A bomb like this almost certainly is not contact fused. It would probably be fused based on radar altitude. On Sun, Sep 22, 2013 at 8:54 PM, graham foulkes wrote= : > Prior Knowledge of what? Its a switch! Any mechanism has a finite chance > of malfunctioning in extreme circumstances or due to lack of foresight > during the design of the said mechanism, ( this is not uncommon in the > design process, we evolve designs based on past experience and current > knowledge which is finite). Look up the failure of tin alloy safety plug= s > in steam boilers as an example of a safety device that was thought to be > robust and always fail safe, just one example, there are lots more. > Graham > > > On Sun, Sep 22, 2013 at 3:29 PM, YES NOPE9 wrote: > > > > > > > On Sep 22, 2013, at 8:05 AM, Mark Hanchey wrote: > > > > > > On 9/21/2013 4:32 PM, enkitec@gmail.com wrote: > > >> > > > http://www.usatoday.com/story/news/nation/2013/09/20/north-carolina-atomi= c-bomb/2845381/ > > >> > > >> Mark Jordan > > > > > > It is old news . While 3 of the 4 safety mechanisms failed it still > > > would not have gone off because the last switch is something that ha= s > > > zero chance of ever contacting by accident, even in an explosion. I > > > can't give exact details because of prior knowledge but picture a > switch > > > that has to be operated like a combination lock for the switch to clo= se > > > contacts. > > > > > > > Old news perhaps ...... zero chance of contacting by accident.... 0.00= 0% > > is a reassuring claim. Mark.... are you saying this switch could not b= e > > forced to close by high G forces or by being crushed ? I guess that is > > what you are saying since you say the switch is not vulnerable to an > > explosion. I keep thinking about the wires that lead to and from this > > switch...... or is everything ( including the detonator ) encased in > armor ? > > Gus > > -- > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > > View/change your membership options at > > http://mailman.mit.edu/mailman/listinfo/piclist > > > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .