Originally Posted by Milt
Whilst investigating the innerds of a RAAF Lincoln I came across a little device in the nose in which I could clearly see a shiny steel ball about 3 cm in diameter. I poked my finger to move the ball and was dismayed to hear a whole bunch of small bangs throughout the aircraft. All engine fire bottles had fired and perhaps some fueslage ones as well. I felt like P/O Prune as much effort was involved in replacing all of the bottles.
Thank you Milt this gave me a good laugh !!
(Were they BCF bottles ? Nice mess I bet !)
These types of crash switches are also fitted to older fast jets eg Harrier GR3 from memory, and are also known as Inertia switches. Basically they consist of a spring detent holding a small mass. In the event of a crash ie high G the mass overcomes the spring detent and makes a set of contacts to complete the firing circuit to the fire bottle.
We used to test them by banging the switch with a hide face hammer (Having previously disconnected the fire bottle
) It took some banging to get them to trip, and you had to remember to reset them before reconnecting the bottles !!
Don't know what the G loading required to trigger them was but well above the usual +9/-3 I would imagine, Becuase thats what the A/C was rated at in normal ops.
I'm not sure what the Lincoln G limits are (does it have a G meter ?) But I'm sure it's not as high as the Harriers so consequently the Inertia switches could well be of a lower rating and far easier to trigger !