AD/PDH/7 - Barrel Support Blocks - Modification

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, serve as a comprehensive legal framework governing civil aviation safety and operations within Australia. A specific focus of these regulations is on the airworthiness of aircraft and their components, ensuring that all aircraft meet stringent safety standards. One such regulation, AD/PDH/7, pertains to the modification of barrel support blocks in certain de Havilland propellers, specifically those of models PD136/212/1, PD170/212/1, and PD175/212/1 fitted to DH114 aircraft. This airworthiness directive was introduced to address issues related to the structural integrity of these propellers, ensuring they maintain their operational safety and reliability. The objective of this directive is to enhance the safety of civil aviation by mandating specific modifications to the propellers post their next overhaul following 21 March 1968, as detailed in the Hawker Siddeley MNS Series 2 BCS No. 87 (Mod. No. 29104). This legislative instrument underscores the Civil Aviation Safety Authority's commitment to maintaining high safety standards in the aviation sector, ensuring that all aircraft and their components adhere to necessary safety directives to protect both the public and aviation personnel. The directive is an integral part of the overarching goal to prevent accidents and ensure the safe operation of aircraft within Australian airspace.

Scope and Application

The Civil Aviation Regulations 1998, as part of the broader legislative framework administered by the Civil Aviation Safety Authority, specifically addresses the airworthiness of aircraft components through various airworthiness directives. In this context, AD/PDH/7 focuses on propellers for De Havilland aircraft, particularly those with variable pitch propellers of model numbers PD136/212/1, PD170/212/1, and PD175/212/1 fitted to DH114 aircraft. The directive mandates compliance with modifications to barrel support blocks before installation in an aircraft following the next overhaul completed after 21 March 1968, as detailed in Hawker Siddeley MNS Series 2 BCS No. 87 (Modification No. 29104). This directive applies specifically to the mentioned propeller models and aircraft type, ensuring that any overhauls conducted after the specified date incorporate the necessary modifications to maintain airworthiness standards. The geographic and jurisdictional reach of this regulation is national, as it is a Commonwealth regulation under the Civil Aviation Act 1988, applying uniformly across all states and territories of Australia. The directive does not explicitly state any exclusions, exemptions, or thresholds, but it implicitly applies only to the specified propeller models and aircraft. The application and enforcement of these regulations may be further detailed or extended through subordinate instruments issued by the Civil Aviation Safety Authority.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39 - 107 under the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives, includes a directive concerning propellers for De Havilland aircraft, identified as AD/PDH/7 (Section 1). This directive mandates the modification of barrel support blocks for certain propeller models, namely PD136/212/1, PD170/212/1 and PD175/212/1, that are fitted to DH114 aircraft. The directive references Hawker Siddeley MNS Series 2 BCS No. 87 (Mod. No. 29104) as the document outlining the required modifications (Section 2). Compliance with this directive is mandatory and must be completed before the next overhaul of the propeller after 21 March 1968 (Section 3). The obligations imposed by this directive are clear and specific. Owners and operators of DH114 aircraft fitted with the mentioned propellers must ensure that the barrel support blocks are modified according to the Hawker Siddeley MNS Series 2 BCS No. 87 (Mod. No. 29104). This involves not only the physical modification of the propellers but also ensuring that all modifications are performed by qualified personnel and documented properly. Compliance must be demonstrated before the next overhaul post-dated 21 March 1968, indicating a timeline that aircraft owners must adhere to for safety reasons (Sections 2 and 3). Failure to comply with the airworthiness directive AD/PDH/7 could result in serious safety implications and legal consequences. While the specific penalties for non-compliance are not detailed in the legislative instrument provided, the general provisions of the Civil Aviation Regulations 1998 indicate that non-compliance with airworthiness directives can lead to enforcement actions. Such actions may include fines, suspension or revocation of aircraft certificates, and potentially criminal charges depending on the severity and impact of the non-compliance. The exact penalties would be determined by CASA and could vary based on the specific circumstances of the breach (Section 4).