3.2 Aircraft Systems and Flight

No matter how you look at it, failure of the main rotor hub retention nut on a helicopter can and will lead to catastrophe if the aircraft is already in flight. Affectionately known as the "Jesus Nut", if this one part fails, the only thing left for the flight crew to do is pray to Jesus. That's because this particular piece of securing hardware is the only thing connecting the rotor assembly (rotor blade, blade grips, control rods, etc.) to the rotor mast which provides the rotation. With no main rotor the aircraft will literally drop out of the sky.

       

Some current generation helicopters do not have this type of hardware, but most still do. As aerospace engineers progress into different design characteristics, there may be better ways to secure this critical piece to the airframe. For now, ensuring the nut is free from corrosion and always properly torqued is the best way to prevent failure.


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Image #1 - Retrieved from https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg8Gv4g2uwPulYPAR-z4B9aFbE5r_RhmO9UGo3VLqA38fDv-EWhDRiVebaEceY6hm_fDUaiAydjKi_mVchYPk-AZxrcvmnksU2Buf6YganV3IbT5HpBrG_KiwGmVwDsCTZ7nQDK7wtxrDg/s320/jesus_nut_helicopter.gif

Image #2 - Retrieved from https://image.jimcdn.com/app/cms/image/transf/dimension=456x10000:format=jpg/path/sdccddb58c2347489/image/i353855190ae8611f/version/1546877353/jesus-nut-helicopter.jpg

Image #3 - Retrieved from https://www.ocregister.com/wp-content/uploads/migration/kpj/kpjj8j-b78395062z.120080901211719000gi3dstpr.1.jpg?w=620