My Skymaster Hawk also lost its canopy in flight, landed safely, cause: The ply plates under the socket head bolts which retain the engine hatch had worn and compressed . The engine hatch retains the canopy and the slightly loose engine hatch, resulting from the compressed ply plates around the keyhole, had allowed the canopy latch to pull clear. Off goes the canopy. So if you have a Hawk/T45 check this area carefully.

I have modified my AW Hawk canopy retention as a result of this incident, see the AW Hawk build thread.

Regards, David Gladwin.