Along the top of some fighter canopies there is a jagged, approx. one inch line. What's it's purpose?

Question

Along the top of some fighter canopies there is a jagged, approx. one inch line. What's it's purpose?

Answer 1

I have been told it is like detonation. cord, i.e. explosive cord or line to shatter the canopy just prior to the pilot's ejection. You don't want your ejection seat to slam you into the canopy above you.

Answer 2

Larry has it correct. Normally, the canopy jettisons just before the seat goes, but in case that pyro fails, the pilot can eject through the canopy without injury.

In older fighters, we just had a "canopy breaking" headrest to do the job. The headrest stuck up about two inches above your head so that it shatered the canopy before your head did the job.

Answer 3

Larry you are correct, it is part of the Canopy Destruct System. Designed to fracture the canopy before the pilot exits (part of the two stage ejection system)

Cheers

Answer 4

What Thudley describes is correct. It is also refered to as a "guillotine" system. A canopy breaker on each side of the headrest pivots upwards, shattering the canopy.