For reference, here is a snip from the AMM (r7, 52-10-00, page eight):
The root cause is a press-fit barrel on the canopy locking bolt that worked loose.
Here is a "normal" locking bolt:
Here is the defective locking bolt:
Somehow the barrel worked loose and slipped forward into the PTFE bushing in the canopy frame. This exposes the sharp machined edge of the locking bolt tip, which readily catches on the outside edge of the frame. No reasonable amount of force is going to overcome the problem if this jams. The canopy handle assembly will probably break first.
Removing the canopy handle and rods is a giant PITA. Unscrewing the outer tip might work, but the connecting rod started to twist before the tip worked loose, and the stainless (non-magnetic) barrel was still inside the frame. Attempting to fix the problem while in a steep climb was clearly the start of an NTSB report.
So after a bit of our solution was:
- Remove the canopy completely (requires three people)
- Tip the canopy aft to expose the barrel
- Clean exposed metal surfaces
- Apply Loctite 271 (red)
- With high-quality pliers, firmly force the barrel onto the locking bolt "shoulder"
- Don't use the latch for several hours
Chris