AD/F50/67 - Main Landing Gear Drag Stay Tubes

Overview

The Civil Aviation Regulations 1998, as amended by the Legislative Instrument F2006B09896, introduce Airworthiness Directives (AD) to address specific safety concerns related to the Fokker F50 (F27 Mk 50) series aeroplanes. This particular AD, numbered AD/F50/67, was enacted to address the problem of main landing gear drag stay tube failures that could potentially lead to catastrophic consequences during flight. The Civil Aviation Safety Authority, as the relevant regulatory body, introduced this directive to mitigate the risk associated with incorrectly machined drag stay tubes, which had been identified as the cause of a previous failure leading to a collapsed landing gear. The policy objective of this directive is to ensure the safety and airworthiness of Fokker F50 aircraft by requiring ultrasonic inspections, removal of defective tubes, and re-identification of compliant tubes in accordance with specified service bulletins and regulatory requirements.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, issued by the Civil Aviation Safety Authority, establish stringent safety requirements for Fokker F27 Mk050 series aircraft fitted with main landing gear drag stay tube P/N 200684001. The regulations mandate an ultrasonic inspection to confirm the installation of a straight bore tube, in accordance with Dowty Aerospace Service Bulletin F50-32-50, and require the removal of any stepped bore tubes from service. Additionally, all identified straight bore tubes must be re-identified with P/N 200684004. These requirements are imperative to prevent structural failures like the one reported, where a crack in an incorrectly machined step led to the collapse of the landing gear. Compliance with these directives must be achieved before 20 September 1995 for in-service aircraft, and for spare tubes prior to their installation on an aircraft. The regulations are enforced across the Commonwealth of Australia, ensuring uniformity in safety standards and compliance within the national airspace.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, include a schedule of airworthiness directives, with AD/F50/67 addressing the Fokker F50 (F27 Mk 50) series aeroplanes. This directive pertains to the main landing gear drag stay tubes of Fokker F27 Mk050 series aircraft equipped with main landing gear drag stay tube P/N 200684001. The directive requires three main actions: first, an ultrasonic inspection of the drag stay tube as outlined in Dowty Aerospace Service Bulletin F50-32-50 to ensure that a straight bore tube is installed (Requirement 1). Second, the removal of all stepped bore tubes from service (Requirement 2). Lastly, re-identification of all straight bore tubes with the new part number P/N 200684004 (Requirement 3). The directive notes that RLD AD 93-169/2 and Fokker SB F50-32-029 are also relevant. Compliance with AD/F50/67 necessitates that inspections are completed in accordance with Requirement 1 before 20 September 1995, and any spare tubes must be inspected before being installed on an aircraft. Additionally, tubes must either be removed from service or re-identified in line with Requirement 3 before further flight. This ensures that all aircraft comply with the safety standards set forth by the Civil Aviation Safety Authority. The directive addresses a reported instance of a failed drag stay tube on an F27 aircraft, which caused the landing gear to collapse due to a crack originating from an incorrectly machined step on the tube interior. By implementing AD/F50/67, the aim is to prevent such incidents by ensuring that all potentially faulty tubes are identified and removed from service, thereby enhancing aircraft safety. There are no explicit offences, penalties, or consequences mentioned for non-compliance with AD/F50/67 within the directive itself. However, under the Civil Aviation Act 1988, non-compliance with airworthiness directives can lead to significant civil and criminal penalties. Civil penalties may include fines, while criminal penalties could result in imprisonment, reflecting the serious nature of ensuring aviation safety. The exact penalties would depend on the specific circumstances of non-compliance and any additional regulations in force at the time.