Nas523 Pdf Link

Often identifies an MS20426AD rivet (countersunk 2117 alloy). ↗️ Northeast (NE): Diameter & Head Placement

A "captive" washer (NAS523) is pre-assembled onto the screw or bolt and cannot be removed without damaging it. A "free" washer (like AN960) slides on and off. Do not substitute one for the other; captive washers are used for high-vibration environments like engine cowlings. nas523 pdf

The is a critical shorthand system used in the aerospace industry to communicate complex fastener specifications on engineering drawings . Rather than cluttering a technical diagram with text, engineers use a single "crosshair" symbol to consolidate multiple data points about a rivet's installation . The NAS523 Crosshair Symbol Often identifies an MS20426AD rivet (countersunk 2117 alloy)

The is a cornerstone of aerospace manufacturing and maintenance. It provides a standardized symbolic system—often referred to as the NAS523 Rivet Code —used on engineering drawings to specify exactly which permanent fasteners are required for a particular location. Do not substitute one for the other; captive

The NAS523 PDF is a detailed document that outlines the technical requirements and recommendations for NAS devices. The specification covers various aspects of NAS design, including: