AD/ENST 28/6 - Pre-Certification Requirements - Modifications - CANCELLED

This document officially scraps an outdated aviation safety rule for Enstrom F-28 helicopters.

What it does

• Cancels Airworthiness Directive (AD) ENST 28/6 — a safety instruction first issued in 1975
• Takes effect on 27 August 2009

Why it exists The original 1975 rule required specific modifications to these helicopters to meet an old safety standard (called ANO 101.24). That standard no longer exists, and the deadline to make the changes was 31 March 1975 — over 30 years ago. Because the rule is obsolete and serves no current safety purpose, the Civil Aviation Safety Authority (CASA) is formally removing it.

Who it affects Owners and operators of Enstrom F-28 series helicopters. In practice, this simply cleans up the rulebooks by removing a defunct requirement that was already impossible to comply with (or was complied with decades ago).