Jesus nut

Origin of name

The term Jesus nut may have been coined by American soldiers in Vietnam; the Vietnam War was the first war to feature large numbers of soldiers riding in helicopters. The term may also have originated with the PBY Catalina, which had two Jesus bolts holding the wing onto the fuselage.

If the Jesus nut were to fail in flight, the rotor would detach from the helicopter, hence the idea that all that would then be left for the crew to do would be to "pray to Jesus." The nut/pin must be checked before the flight, even though real-world examples of the Jesus nut/pin failing are rare. For example, in 2000, the mast nut of a Bell 206B was removed to be repainted and was not restored and checked prior to a test flight. The helicopter crashed within ten minutes of takeoff, killing the two occupants.

Other contexts

More recently, the term has been more generically applied throughout engineering to include any single component whose failure would cause catastrophic failure of the entire system.

Another use for the term is found in rock climbing, in which it refers to the first piece of protection (some of which are also called "nuts") placed on a pitch.

In literature, the term "Jesus nut" first appeared in print in Elaine Shepard's 1967 book The Doom Pussy, a recollection of her experiences with aviators in the early part of the Vietnam War. It was later popularized in Chickenhawk by Robert Mason, a narrative about his experiences as a pilot in the war.

Marine M60A1 tankers used the term "Jesus pin" in reference to a breech pin located on the 105mm main gun that needed to be removed in order to disassemble the breech block. Dropping the small pin would cause it to instantly disappear into the bowels of the tank's hull causing one or more members of the crew to cry out "Jesus" as an expletive.

Notes

References

References

1. "Main Rotor Installation diagram".
2. Rottman, Gordon L.. (2020). "Grunt Slang in Vietnam: Words of the War". Open Road Media.
3. Joiner, Stephen. (April 2019). "Legends of an Ocean-Crossing Seaplane". Smithsonian Institution.
4. (June 1992). "Failure Analysis of the Main Rotor Retention Nut from the AH-64 Helicopter, MTL TR 92-39". U.S. Army Materials Technology Laboratory.
5. (18 December 2001). "Aviation Investigation Report A00Q0046". Transportation Safety Board of Canada.
6. (2002). "Aviation Safety Maintainer 1/2002: Fatigue and Complacency - A Potentially Sorrowful Mixture". Transport Canada.
7. (2006). "Climbing Anchors". Falcon Press.
8. (1967). "The Doom Pussy". Trident Press.
9. Robert Mason. (29 March 2005). "Chickenhawk". Penguin Publishing Group.