FAA Aviation Mechanic General (AMG)Materials, Hardware and ProcessesMedium
A technician is safety-wiring two adjacent bolts using the double-twist method. Which practice is correct to ensure the safety wire performs its intended function?
- ARoute and twist the wire so that any tendency of the bolts to loosen further tightens the wire
- BApply only one twist for every three inches of wire length
- CTwist the wire in the direction that would loosen the fasteners if they moved
- DTwist the wire loosely so it can be removed by hand for future maintenance
Show answer & explanationAnswer & explanation
Correct answer: A. Route and twist the wire so that any tendency of the bolts to loosen further tightens the wire
Safety wire must be installed under tension with 6-8 twists per inch, routed so that any rotation of the fastener toward loosening instead pulls the wire tighter, preventing the fastener from backing off. Loose wire or wire routed to allow further loosening defeats its purpose.
Why the other options are wrong
- B. Standard practice is 6-8 twists per inch, not one twist per three inches.
- C. This is backwards and would allow the fastener to loosen further.
- D. Loose wire provides no locking tension and is improper installation.
Safety Wire Installation
Safety wire mechanically prevents fastener rotation by being installed taut, with proper twist density, routed so loosening motion tightens the wire.
- 6-8 twists per inch for standard 0.032 in wire
- Wire must be in tension, not slack
- End must be bent into a pigtail away from sharp edges
Memory trick: 'Loosen tries to escape, wire drags it back'