which accomplish a similar objective as safety wire, which is to prevent nuts backing off (falling off). Locknuts such as Nyloc Nuts and HARDLOCK Nut have the additional objective of preventing lost bolt tension. Loss of bolt tension can cause Fatigue failure in the joint. References Further reading Aviation Publication (AvP) 970 dated 1959:Design Requirements for Service Aircraft Air Publication (AP) 970 2nd Edition dated 1924:Handbook of Strength Calculations Handbook (HB) 806 1st Edition dated 1918:Handbook of Strength Calculations The Society of British Aerospace Companies Ltd Reference Sheet 697 – The Wire Locking of Threaded Items External links The Use of Lock Wire – A Guide Safety equipment Fasteners