A friend flew his new Harrier 60 a few weeks before I conpleted my Harrier 46. His canopy also came off in flight, luckly landing in some unmown hay with no damage. When I flew my Harrier 46 the time, I put a small drop of blue loctite on each canopy bolt. I've done that at the start of each flying session since. Blue loctite is designed to be removed with moderate force, plus it usually takes overnight to fully harden. I've had no problems removing the canopy bolts and no problems with them falling out.