Canopy locking mechanism

[Barry]

I had a very strange occurrence the other day upon landing. Just as I touched down, I heard the door alarm. I quickly looked over and the door had become unlatched. I continued my roll-out (which was supposed to be a touch and go) and taxied back to the maintenance hangar. It was immediately obvious that the secondary (small inner) locking lever was not working, allowing the canopy lock to open with a single touch, or in this case no touch at all. As my A&P and I played around with it, we found that if the key lock was in the locked position, the door latch operated normally from inside with the need to move both the main and secondary levers. Obviously this is not correct. The key lock must be in the unlocked position during flight per the manual. But with the key lock in the unlocked position, the secondary lever had no effect. Has anyone seen this before? Am I correct that the locking spring is probably DOA?

Thanks,

Barry Starkman, Commercial - Instrument
DA40 - 40.827 N984ES
KEIK, Erie Colorado

[Diamond13]

Barry, here is a link to a maintenance manual revision, your issue may be related to the gas strut, which holds the over-center mechanism from unlocking. Over time the gas can leak from the strut, hence a 3000 hour/6 year time limitation has been added.

http://support.diamond-air.at/fileadmin ... 40-846.pdf