AD/F28/48 Amdt 1 - Horizontal Stabilizer Control Unit Cavity Venting

Overview

The Civil Aviation Regulations 1998, as amended by F2006B09782, address specific safety concerns related to the Fokker F28 Series aeroplanes, particularly focusing on the horizontal stabilizer control unit cavity venting. This legislative instrument was enacted to ensure that all Fokker F28 aeroplanes with specific serial numbers are fitted with vented plugs to prevent hydraulic build-up in the cavity between hydraulic systems 1 and 2. This change was prompted by incidents where leakage of a clutch piston seal led to increased seal friction and a decrease in control unit reliability. The objective of this Airworthiness Directive is to enhance the safety and reliability of these aircraft by implementing specific maintenance actions as outlined in Fokker SB F28/27-161 and Menasco SB27-93. Compliance with this directive is mandatory, with a compliance deadline set before further flight after 30 September 1985. This amendment was introduced by the Civil Aviation Safety Authority to ensure that the operational risks associated with the described issue are adequately mitigated.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to the Fokker F28 Series Aeroplanes as delineated by the Airworthiness Directive AD/F28/48 Amendment 1, which mandates horizontal stabilizer control unit cavity venting. This directive applies to all Fokker F28 models with specific serial numbers and those fitted with Horizontal Stabilizer Control Units P/No. 11100, irrespective of dash numbers or serial numbers excluding certain specified serial numbers. The directive's requirements are actioned in accordance with Fokker Service Bulletin F28/27-161 and subsequent issues, as well as Menasco Service Bulletin 27-93. Notably, compliance with this directive is mandatory before further flight after 30 September 1985 to prevent hydraulic leakage from causing increased seal friction and decreased control unit reliability. The directive has been amended to clarify the serial numbers involved, removing any prefixes. This legislative instrument extends its jurisdiction across the Commonwealth of Australia, ensuring adherence to civil aviation safety standards.

Key Provisions

The Civil Aviation Regulations 1998, specifically in Part 39, section 105, detail the Civil Aviation Safety Authority’s (CASA) Schedule of Airworthiness Directives (AD) for the Fokker F28 Series Aeroplanes. The directive in question, AD/F28/48 Amendment 1, pertains to the Horizontal Stabilizer Control Unit Cavity Venting. This directive applies to all Fokker F28 aircraft with specific serial numbers and those equipped with Horizontal Stabilizer Control Units with particular part numbers. The requirement outlined in this directive is that affected aircraft must undertake actions in accordance with Fokker Service Bulletin F28/27-161 and subsequent issues, as well as Menasco Service Bulletin 27-93. These service bulletins detail the necessary modifications to replace existing closed plugs with vented plugs to prevent hydraulic build-up within the cavity, which can lead to increased seal friction and decreased control unit reliability. Operators of the Fokker F28 aircraft covered by this AD must ensure compliance with the specified service bulletins. Compliance is mandatory before any further flight after 30 September 1985. This means that operators need to review their aircraft's serial numbers and part numbers to determine if they fall within the scope of this directive. If they do, the required modifications must be carried out before the aircraft can be flown again. This directive is a critical safety measure aimed at preventing potential hydraulic issues that could compromise the aircraft's control reliability. Breach of the requirements outlined in AD/F28/48 Amendment 1 can result in significant consequences. Under the Civil Aviation Act 1988, failure to comply with an Airworthiness Directive can lead to enforcement actions by CASA. This may include fines, penalties, and potential grounding of the aircraft. The severity of the penalties can vary based on the nature and extent of the non-compliance. In some cases, persistent non-compliance could also lead to more severe civil or criminal penalties, depending on the circumstances and the impact on aviation safety. Ensuring compliance with this directive is, therefore, not only a legal obligation but also a crucial step in maintaining the safety and airworthiness of the aircraft.