MS20995AB20

Source notes and limits

• ** "TO BE USED AS SAFETY WIRE OR LOCK WIRE ACCORDING TO NOTE (3)." Note (3): "ALUMINUM ALLOY (AB) USE FOR LOCK WIRE WITH MAGNESIUM."
• Examples (sheet 1): "MS 20995 CY20 - COPPER, CADMIUM PLATED, YELLOW, SHEAR OR SEAL WIRE, .020 DIA. MS 20995 AB32 - ALUMINUM ALLOY, ANODIZED, BLUE, .032 DIA."
• "FOR SAME DIAMETER AND LENGTH NI-CU ALLOY (MONEL) WIRE CAN BE SUBSTITUTED FOR CARBON STEEL AND CORROSION RESISTANT STEEL WIRE." (sheet 2).
• Material specification numbers on the scan are not legible enough to transcribe; see the sheet.
• "DASH NUMBERS INDICATE WIRE MATERIAL AND DIAMETER IN THOUSANDTHS OF AN INCH. ADDITIONAL DASH NUMBERS INDICATING LENGTH IN INCHES ARE FOR REFERENCE ONLY AND SHALL NOT BE USED FOR PROCUREMENT OR STOCKING." (MS20995E sheet 1).
• MS20995E, dated 17 SEPTEMBER 1974, is hereby canceled and superseded by NASM20995. The Part Identification Numbers (PIN) for MS20995E and the part numbers for NASM20995 are identical. The part numbers have not been changed. (Notice 4, 12 June 1998).
• FAA AC 43.13-1B para 7-123 (p.7-19): "SAFETY WIRE. Do not use stainless steel, monel, carbon steel, or aluminum alloy safety wire to secure emergency mechanisms such as switch handles, guards covering handles used on exits, fire extinguishers, emergency gear releases, or other emergency equipment. Some existing structural equipment or safety-of-flight emergency devices require copper or brass safety wire (.020 inch diameter only)."
• FAA AC 43.13-1B para 7-123b (p.7-19): "When using double-twist method of safety wiring, .032 inch minimum diameter wire should be used on parts that have a hole diameter larger than .045 inch. Safety wire of .020 inch diameter (double strand) may be used on parts having a nominal hole diameter between .045 and .062 inch with a spacing between parts of less than 2 inches. When using the single-wire method, the largest size wire that the hole will accommodate should be used."
• FAA AC 43.13-1B para 7-124e (p.7-21): "Safety wire must never be overstressed. Safety wire will break under vibrations if twisted too tightly. Safety wire must be pulled taut when being twisted, and maintain a light tension when secured."
• FAA AC 43.13-1B para 7-124g(2) (p.7-21): "Safety wire must not be nicked, kinked, or mutilated. Never twist the wire ends off with pliers; and, when cutting off ends, leave at least four to six complete turns (1/2 to 5/8 inch long) after the loop. When removing safety wire, never twist the wire off with pliers. Cut the safety wire close to the hole, exercising caution."
• FAA AC 43.13-1B para 7-38 (p.7-6): "LOCKING OR SAFETYING OF BOLTS. Lock or safety all bolts and/or nuts, except self-locking nuts. Do not reuse cotter pins or safety wire."