The term Jesus nut has to do with Helicopter maintenance and refers to the one piece of hardware that holds the entire rotor system in place. The term was coined by Mr. Dr. Igor Sikorsky, the inventor of the rotor wing aircraft and the implication was that, should this small bit of machined metal fail in flight, the crew and anyone else aboard would be meeting Jesus as a bonus for suffering a horrible death. Now Dr. Mr. Sikorsky was a deeply religious person, so he probably meant the whole deal about the Jesus Nut and wasn't being cute.
In fact the whole Jesus Nut issue might have stayed locked in inquiring minds had it not been for the Vietnam War; the first war fought by the helicopter. What this came to mean was where the old time cavalry trooper would know about the diamond hitch to tie a load on a mule his modern counterpart knew how and when to check the Jesus Nut and other various and sundry things that would keep the "bird" in the air doing it's important work of dropping off the Troop for a fight and coming back to get them. Funny thing is Sikorsky did not have a lot of copters in the war. Today, almost all the helicopters in the military i.e. The Black Hawk and Sea Hawk are made by Sikorsky, but when people think Vietnam, they think about The Huey which looks like a mini van with sliding doors and all. It is a turbine (jet) and only has two main rotor blades. That means it is not particularly good at flying straight up off the ground and likes to have a running start. A person might get in trouble because he could easily put the helicopter into a spot where he cannot get out without some fancy and dangerous trick flying. When I was in Vietnam, I always worried over the state of the helicopter and had this fear that I would be flying along and suddenly catch site of Jesus floating by tossing my. Jesus nut in the air and catching it. You see it's quite possible to land a helicopter with no power so long as the transmission is not seized and the rotor will spin. Of course if Jesus has the Jesus Nut, the rotors will come off and the craft will fall like a stone leaving you to meet your maker as Pancake People.
I know that this is not a very clever of funny post, but it does contain information you can use.