AD/PA-22/17 - Cabin Heater Box Plate - Modification - CANCELLED

What this does: This document cancels an old aviation safety rule (called an Airworthiness Directive or AD) that previously required owners of specific light aircraft to modify a cabin heater component.

Who it affects: Owners and operators of Piper PA-22 Tri-Pacer and Colt series aeroplanes—specifically those manufactured in 1961 that had not already undergone the modification.

What changed: The original rule required a one-time modification to the cabin heater box plate (following Piper Service Bulletin No. 203). As of 3 July 2008, this requirement is completely removed. Aircraft owners no longer need to comply with this directive.

Why it matters: The safety modification only applied to aircraft built in 1961. By 2008, aviation safety authorities determined that every affected plane would have been modified decades ago, making the rule redundant. This cancellation eliminates an unnecessary compliance burden while maintaining safety standards.