AD/SD3-30/20 - Landing Gear Warning Horn

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, form a comprehensive regulatory framework designed to ensure the safety and efficiency of civil aviation within the country. One specific instrument, F2006B06822, addresses issues related to the airworthiness of aircraft, particularly focusing on landing gear warning horns in the SD3-30 series aeroplanes. This regulation was introduced to address a problem identified with the audibility of the landing gear warning horn, which was found to be inaudible when positioned between specific stations on the aircraft's top centre line. The primary objective of this legislative instrument is to enhance aviation safety by ensuring that critical warning systems are effective and reliable. The regulation, AD/SD3-30/20, mandates that upon replacement of the Lucas Horn P/No. V.0603L with the Keystone Horn P/No. AC155F, the mounting of the horn must be relocated according to the specifications outlined in the Shorts SD3-30 Service Bulletin SD330-32-114. For aircraft previously fitted with the Keystone Horn P/No. AC155F, the horn's mounting must also be relocated following the same guidelines. Compliance with these requirements is crucial, with the mandate for replacement to occur upon the specified change and for other adjustments to be completed within 30 hours of time in service after 31 January 1987. This directive aims to mitigate risks associated with the inaudibility of the landing gear warning system, thereby contributing to overall aviation safety.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, addresses the safety directives concerning the airworthiness of aircraft, with the focus of the particular legislative instrument SD3-30/20 on the landing gear warning horn of SD3-30 series aeroplanes. This regulation applies to all SD3-30 models with serial numbers ranging from SH3002 through SH3107 and SH3109 through SH3120. The directive mandates that upon replacement of the Lucas Horn P/No. V.0603L with a Keystone Horn P/No. AC155F, the mounting of the horn must be relocated in accordance with the requirements outlined in Shorts SD3-30 Service Bulletin SD330-32-114. Additionally, for aeroplanes that were previously equipped with the Keystone Horn P/No. AC155F, the horn's mounting must also be relocated as per the aforementioned service bulletin. Compliance with these directives requires that the specified changes be made upon the replacement of the horn for new installations and within 30 hours of time in service after 31 January 1987 for existing installations. This legislative instrument is applicable across the Commonwealth of Australia and is enforced by the Civil Aviation Safety Authority.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39 - 105, mandate that certain aeroplanes undergo modifications to their landing gear warning horn as outlined in Schedule of Airworthiness Directives (AD/SD3-30/20). For all models SD3-30 with serial numbers ranging from SH3002 through SH3107 and SH3109 through SH3120, there are two key requirements (section 1). Firstly, if the Lucas Horn P/No. V.0603L is replaced with the Keystone Horn P/No. AC155F, the mounting of the horn must be relocated in accordance with the specifications given in Shorts SD3-30 Service Bulletin SD330-32-114 (section 1(1)). Secondly, for aeroplanes already equipped with the Keystone Horn P/No. AC155F, the horn's mounting must also be relocated according to the same service bulletin (section 1(2)). Compliance timelines are set to ensure that these modifications are performed in a timely manner. Specifically, if a replacement of the horn occurs, the relocation must be completed upon replacement (section Compliance: Para 1). For aeroplanes already equipped with the Keystone Horn, the relocation must be performed within 30 hours of time in service after 31 January 1987 (section Compliance: Para 2). The Civil Aviation Regulations impose specific obligations on the parties and entities governed by these directives. Aircraft operators and maintenance providers must ensure that any replacement or relocation of the landing gear warning horn follows the prescribed procedures. This involves adhering to the guidelines set out in the referenced service bulletin, which details the precise mounting requirements to address the issue of inaudibility between station 3 and 13.45 on the aircraft's top centre line. The regulations necessitate that these modifications be made to ensure the continued safety and compliance of the aircraft with airworthiness standards. Failure to comply with these directives can result in significant consequences. The Civil Aviation Regulations do not explicitly state the penalties for non-compliance within the provided text, but generally, breaches of airworthiness directives can lead to severe penalties. These can include administrative fines, suspension or revocation of airworthiness certificates, and potential criminal charges if the non-compliance leads to an aviation incident or accident. The seriousness of these consequences underscores the importance of adhering to the requirements outlined in the Airworthiness Directives to maintain the safety and integrity of aviation operations.