AD/BEECH 76/11 - Elevator Down Cable

Overview

The Civil Aviation Regulations 1998, under Part 39 - 105, encompasses the Civil Aviation Safety Authority’s Schedule of Airworthiness Directives, which was enacted to ensure the safety and reliability of aircraft operating within Australia. This regulation was introduced to address the critical issue of maintaining the structural integrity and safety of aircraft components, particularly in preventing in-flight failures. The policy objective behind this regulation is to ensure that aircraft remain airworthy and that any identified risks to flight safety are mitigated through mandatory maintenance and inspection directives. The enacting body for these regulations is the Commonwealth of Australia’s Parliament, reflecting the national importance of ensuring safe civil aviation practices. This directive specifically targets the Beechcraft 76 (Duchess) Series Aeroplanes, addressing the problem of elevator down cable failures through precise maintenance instructions to prevent potential catastrophic incidents.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105 and the Airworthiness Directive AD/BEECH 76/11, apply to all Beechcraft 76 (Duchess) series aeroplanes with serial numbers ranging from ME-1 to ME-435. These regulations mandate specific procedures concerning the elevator down cable to mitigate the risk of in-flight separation of the elevator control cable, a concern stemming from documented incidents overseas. The directive applies to both the removal and inspection of the large inspection panel, drilling of a specified inspection hole, deburring and visual inspection of the elevator down cable, and the replacement of certain parts if the cable is misrouted over the guard pins. This regulation applies nationwide, under the jurisdiction of the Civil Aviation Safety Authority, ensuring compliance across all operational flights within Australia. Notably, aeroplanes with serial numbers ME-418 and subsequent already have the required inspection hole drilled, streamlining compliance for these specific aircraft.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, include the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, which cover a variety of aircraft models and maintenance requirements. The particular directive AD/BEECH 76/11 pertains to the Beechcraft 76 (Duchess) Series aeroplanes with serial numbers ranging from ME-1 to ME-435. Section 1 of this directive outlines the requirement to remove the large inspection panel located in the centre of the bottom skin just aft of the Station 68 frame. This is to allow for the drilling of a 3/8 inch diameter inspection hole in the forward flange where the inspection panel was previously attached. The directive specifies that the hole should be centred laterally on the elevator cable pulley and aligned fore and aft on the flange. To prevent damage to the pulley and cable during drilling, a thin bucking bar or wood block should be used between the flange and the pulley and cable. It is noted that aeroplanes with serial numbers ME-418 and subsequent already have this inspection hole drilled. The directive further mandates a series of inspections and potential repairs to the elevator down cable. Section 3 requires deburring of the inspection hole and a visual inspection of the elevator down cable to check for broken or frayed strands. The cable must be ensured to be on the pulley under all three guard pins. If the cable is found to be riding over any of the guard pins, the NAS 427K12 guard pins must be replaced, along with the NAS 314-25-1411 cable, and the cable must be rigged in accordance with the Beech Model 76 Maintenance Manual. Once the necessary inspections and repairs have been completed, the inspection panel must be reinstalled. The directive notes that FAA AD 82-02-03 dated 8 January 1982 is referenced in the directive. Compliance with these requirements is mandatory before any further flight of the affected aircraft. The background information provided indicates that there have been two overseas incidents of in-flight elevator control cable separation due to misrouted cables, underscoring the importance of adherence to these maintenance and inspection procedures. Failure to comply with the provisions of this directive can result in various civil or criminal consequences. While specific penalties are not detailed within the directive itself, non-compliance with CASA regulations generally can lead to enforcement actions by CASA. Such actions can include fines, suspension or revocation of airworthiness certificates, or even criminal charges in severe cases, depending on the nature and severity of the non-compliance. The exact penalties would depend on the specific circumstances and any additional regulatory or legal frameworks that apply.