News and Information

The Jesus Nut

From Wikipedia, the free encyclopedia

The Jesus nut, also called the Jesus pin, is the hexagonal nut that holds the main rotor to the mast of some helicopters, such as the UH-1 Iroquois. It is a slang term first coined by American soldiers in Vietnam; the technical term is main rotor retaining nut.

The origin of the term is the idea that, if the Jesus pin were to fail in flight, the helicopter would detach from the rotors and the only thing left for the crew to do would be to pray to Jesus. Real examples of the Jesus pin failing are few and far between, although in 2002, a civilian helicopter of the Mercy Air Services suffered a "main rotor blade separation", with the death of all those on board. The exact cause was never determined, but it is likely that the Jesus nut failed for reasons unknown 1. Some more recent helicopter systems do not have a Jesus nut.

More recently, it has come to be a generic engineering term, referring to any single component of a system whose failure would cause catastrophic failure of the whole system.

Concerning tandem rotor helicopters it is the part that hold the whole thing together.


The Rattler/Firebird Association, a group of chopper veterans, gives out an annual "Jesus Nut Award" to the member who travels the longest distance to its reunions.

Another group of veterans offers this at "Enjoy the site and may the Jesus Nut stay tight."