That sounds similar to the rumor I heard about the early Glock cases. Supposedly they had a post in the middle of the box that the trigger guard went around. People buying them for home defense would load the pistols, put them back in the box and when they went to put them under the bed or somewhere else, the weight of the pistol on that post would pull the trigger. Since the only safety on the Glock was on the trigger its self, bam ND.

I make no claims about the veracity of this story. But if something similar happened with the pilot, its another example of poorly thought design coupled with a tendency to do things with out fully analyzing the mechanics of what you're doing. It happens to people all the time, especially when follow directions or training.