A Hawker 900XP crew recently discovered after landing that a slightly out-of-tolerance closing mechanism can render the cabin door unopenable from inside the airplane, leaving the emergency hatch as the only exit. Luckily, the pilot was able to radio a lineman to grab the keys through the pilot’s side window and unlock the door handle from outside. After some investigation, the Hawker technician found that the receptacle in the door latch mechanism has a critical tolerance, and this Hawker’s receptacle needed adjustment by two added washers. “It’s a somewhat common problem that crops up on the Hawker,” the pilot told AIN. “It’s a relatively easy fix, just a matter of putting washers under the receptacle. It probably is something that Hawker pilots ought to be aware of. Hopefully mechanics and pilots will check their [Hawker] tolerance. Obviously it’s a big safety issue.” It is also a security issue, this pilot discovered, because in examining the problem he found that when the mechanism is out of tolerance, the locked door handle can be forced from outside to move and open the door. Hawker Beechcraft is investigating this problem, according to a spokesman, “but it sounds like it is a one-off incident.”