AD/CESSNA 337/6 - Control Systems - Modification - CANCELLED

This document officially cancels a 1970 aviation safety rule that required owners of Cessna 337 Series aeroplanes to replace faulty lock nuts on their aircraft control systems.

What it does:

• Cancels Airworthiness Directive AD/CESSNA 337/6 effective 14 February 2008.
• The original rule required a one-time replacement of specific NAS 679 lock nuts (a type of securing fastener) installed on Cessna 337 aircraft between April and November 1969. These nuts had a suspected manufacturing flaw that could compromise flight safety.

Why it matters:

• After nearly 40 years, aviation authorities determined that all affected nuts would have been replaced during routine maintenance, meaning the unsafe condition no longer exists.
• This removes an administrative compliance burden for aircraft owners and mechanics, who no longer need to track or prove compliance with a long-obsolete requirement.