AD/DHC-1/25 Amdt 1 - Wing Flap Inner Hinge Bracket and Reinforcing Channel

Overview

The Civil Aviation Regulations 1998, as amended through the legislative instrument F2006B09006, address safety concerns within the aviation sector by introducing specific airworthiness directives for certain aircraft models. This particular legislative instrument focuses on the De Havilland DHC-1 (Chipmunk) series aeroplanes, establishing requirements for the inspection and maintenance of the wing flap inner hinge bracket and reinforcing channel. Enacted by the Commonwealth of Australia, the policy objective of these regulations is to mitigate the risk of structural failure due to fatigue-induced cracking in these components, which has been linked to the repeated use of the footstep on the flap. This directive aims to ensure the ongoing airworthiness of affected aircraft by mandating regular inspections and maintenance at specified intervals to prevent potential safety hazards. These regulations are a response to identified issues with the Chipmunk series aeroplanes, where cracking in the inner hinge bracket and reinforcing channel has been reported. The enforcement of these specific maintenance requirements is intended to maintain the structural integrity of these aircraft, thereby enhancing flight safety. By setting out clear compliance guidelines and inspection intervals, the Civil Aviation Regulations 1998 aim to ensure that operators adhere to these standards, thereby protecting both the aircraft and those on board.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, pertains to the Civil Aviation Safety Authority's Schedule of Airworthiness Directives for De Havilland DHC-1 (Chipmunk) Series Aeroplanes. This regulation applies to all English production aircraft of this model and mandates specific maintenance and inspection requirements to ensure airworthiness. The regulation outlines detailed procedures for the inspection and reinforcement of the wing flap inner hinge bracket and reinforcing channel to mitigate the risk of fatigue-induced cracking, particularly in the inner hinge bracket and reinforcing channel. Compliance with these directives is mandatory, with the inspection of the inner hinge bracket required within 100 hours of time in service after 30 November 1973, and subsequently at each major inspection or at intervals not exceeding 600 hours, whichever occurs first. The reinforcing channel must be inspected before the issue of the next Maintenance Release after 30 November 1985 and then at each major inspection or at intervals not exceeding 300 hours, whichever is sooner. The regulation references British Aerospace TNS CT(C1) No. 166, Issue 2, for further technical details. The regulation also notes that modification in accordance with Drawing No. RD.C1.WF.104 can serve as a terminating action for the inspections outlined in paragraph 3.2 of the TNS. This directive underscores the importance of regular and rigorous maintenance to ensure the safety and reliability of these aircraft.

Key Provisions

The Civil Aviation Regulations 1998, under Part 39 and specifically in relation to Airworthiness Directives for the De Havilland DHC-1 (Chipmunk) Series Aeroplanes, provide detailed requirements and procedures to ensure the continued safety of these aircraft (Section 39-105). The particular Airworthiness Directive in focus here, AD/DHC-1/25 Amendment 1, concerns the inspection and possible modification of the wing flap inner hinge bracket and the reinforcing channel (Section 39-105). This directive applies to all English production aircraft of the De Havilland DHC-1 series (Section 39-105). The document that details these requirements and the procedure for compliance is the British Aerospace Technical Notice CT(C1) No. 166, Issue 2 (Section 39-105). The directive mandates specific inspection intervals and modification actions to address reported cracking in the wing flap inner hinge bracket and the reinforcing channel. The inner hinge bracket requires inspection within 100 hours of time in service after 30 November 1973, and then at each major inspection or at intervals not exceeding 600 hours time in service, whichever comes first (Section 39-105). For the reinforcing channel, inspections must occur prior to the issue of the next Maintenance Release after 30 November 1985, and thereafter at each major inspection or at intervals not exceeding 300 hours time in service, whichever comes first (Section 39-105). The accomplishment of the modification in accordance with Drawing No. RD.C1.WF.104 is recognised as the terminating action for the inspections mentioned in paragraph 3.2 of the Technical Notice (Section 39-105). Failure to comply with these airworthiness directives can result in significant safety risks, as the cracking in the mentioned components has been attributed to fatigue induced by repeated use of the footstep on the flap. The regulations impose obligations on the operators and maintainers of the De Havilland DHC-1 series aeroplanes to ensure that these inspections and modifications are conducted as specified. Non-compliance with these requirements could lead to severe consequences, including potential grounding of the aircraft and enforcement actions by the Civil Aviation Safety Authority (CASA). Although the specific penalties are not detailed in the provided text, non-compliance with airworthiness directives generally can lead to civil or criminal penalties under the Civil Aviation Act 1988, which may include fines and imprisonment.