AD/DHC-2/29 - Elevator Mass Balance Weight

Overview

The Civil Aviation Regulations 1998, specifically in Part 39 - 105, establish the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, which includes AD/DHC-2/29 concerning the de Havilland DHC-2 (Beaver) series aeroplanes. Enacted to address the identified problem of corrosion in the elevator tip rib underneath the mass balance weights of Beaver aircraft, this directive was introduced to prevent potential in-flight loss of the balance weight and associated flight control difficulties. The objective of the legislation is to ensure the ongoing airworthiness of these aircraft by mandating regular inspections and modifications, as outlined in the directive. Compliance with this airworthiness directive is required before 31 January 1998, and subsequently at intervals not exceeding five years, to maintain the safety standards of the aircraft as stipulated by CASA.

Scope and Application

The Civil Aviation Regulations 1998, specifically PART 39 - 105 SCHEDULE OF AIRWORTHINESS DIRECTIVES, pertains to the maintenance and safety of de Havilland DHC-2 (Beaver) Series Aeroplanes, including the MK I, MK II, and MK III Turbo Beaver aircraft. This legislation applies to all such aircraft within the jurisdiction of the Commonwealth of Australia, mandating rigorous inspection and maintenance requirements to ensure their airworthiness. The requirement includes inspecting the elevator tip rib for any signs of corrosion and implementing specific modifications as outlined in relevant service bulletins. For the MK I and MK II Beaver aircraft, Modification 2/1540 must be installed following the instructions in de Havilland Service Bulletin 2/50, while the MK III Turbo Beaver aircraft must incorporate Modification T2/2079 as per de Havilland Service Bulletin TB/58. Compliance with these directives is mandatory, with an initial inspection deadline set before 31 January 1998, and subsequent inspections required at intervals not exceeding five years. This airworthiness directive became effective on 14 August 1997, addressing concerns raised by field reports of corrosion under the mass balance weights which could lead to in-flight loss of balance weights and potential flight control issues.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39 - 105 under the Civil Aviation Safety Authority (CASA) Schedule of Airworthiness Directives, detail the requirements for DHC-2 (Beaver) Series Aeroplanes, focusing on the elevator mass balance weight. Section AD/DHC-2/29 stipulates the need for inspections and modifications to ensure the structural integrity of the elevator tip rib, particularly in the de Havilland DHC-2 MK I, MK II, and MK III Turbo Beaver aircraft. For MK I and MK II Beaver aircraft, the requirement includes inspecting the elevator tip rib for corrosion and installing Modification 2/1540 as per de Havilland Service Bulletin 2/50. Similarly, for MK III Turbo Beaver aircraft, the directive mandates inspecting the elevator tip rib for corrosion and installing Modification T2/2079 according to de Havilland Service Bulletin TB/58. These measures are aimed at preventing potential loss of the mass balance weight in flight, which could lead to flight control difficulties. The obligations imposed by this legislation on the aircraft operators and maintenance personnel are clear and specific. Operators of de Havilland DHC-2 MK I and MK II Beaver aircraft must ensure that the elevator tip rib is inspected for corrosion before 31 January 1998 and thereafter at intervals not exceeding five years. The inspection and installation of the specified modifications must be conducted in accordance with the detailed instructions provided in the referenced de Havilland service bulletins. For MK III Turbo Beaver aircraft, the same inspection and modification requirements apply, ensuring that the aircraft meet the airworthiness standards set by CASA. Compliance with these directives is crucial for maintaining the safety and airworthiness of the aircraft. Breach of the provisions outlined in this airworthiness directive can result in significant consequences. Failure to conduct the required inspections and modifications on the elevator tip rib can lead to safety risks, potentially resulting in a loss of the mass balance weight during flight. Such a failure could compromise flight control, leading to severe operational and safety issues. While the Civil Aviation Regulations 1998 do not explicitly state penalties for non-compliance in this directive, CASA has the authority to take enforcement actions against operators who fail to adhere to airworthiness directives. These actions can include fines, suspension of airworthiness certificates, and other regulatory measures to ensure compliance and maintain the highest safety standards in civil aviation.