As an ex-maintenance guy, and I've seen it before, 50/50 chance it'll stay on during flight with the crappy hinges being the only thing holding it on. It'll vibrate like hell all the way to destination destroying the original latch so you will need maintenance to fix it anyway since you won't be able to close it ever again. An MEL for speed tape is a fix after that one. But my favorite, the panel will stay on all the way there to be torn off as full reverse is applied sending the panel forward then to be sucked down the engine. Also saw a 767 crew leave a fuel panel unsecured but I'll be damned if the panel stayed on but the fuel cap came off when the T/R/s were activated trashing a very nice GE CF-6 engine. There's an engine change you never want to explain. Swallow your pride, go back and close it for safety's sake. Don't give someone a seniority bump by being stupid.

 

The high pressure air door (used for huffer starts) opens down and there is no way the slip stream would latch it closed. I agree that closing it or deferring it with speed tape is what should be done. I also know what its like in a CRJ with no APU after the long taxi to 17 in the summer time. Any legal creative solutions out there? Park in the pad and have FO close it... maybe MX... ? Returning to the gate for something so easy with almost no A/C is a pain in the A$$.