AD/F28/49 - Wing Butt Straps and Boundary-Layer Fences

Overview

The Civil Aviation Regulations 1998, enacted by the Parliament of Australia, govern various aspects of civil aviation safety, including the maintenance and airworthiness of aircraft. Part 39 of these regulations contains specific airworthiness directives aimed at ensuring the safety of aircraft operations. One such directive, AD/F28/49, pertains to Fokker F28 series aeroplanes, specifically addressing the wing butt straps and boundary-layer fences. This directive was introduced to address the problem of air leakage through the butt straps and boundary-layer fences, which can adversely affect the aerodynamic behaviour of the wings. The directive requires compliance prior to 31 December 1985, referencing Netherlands AD 85-44, with the overarching policy objective being the enhancement of flight safety by mitigating risks associated with identified structural weaknesses.

Scope and Application

The Civil Aviation Regulations 1998, specifically Part 39 - 105, applies to all Fokker F28 series aeroplanes with specific serial numbers, namely S/Nos 11092, 11093, 11111 to 11203 and 11205 to 11231. This legislation mandates compliance with Airworthiness Directive AD/F28/49, which concerns the inspection and maintenance of wing butt straps and boundary-layer fences. The directive is necessary to address issues of air leakage through these components, which adversely affects the aerodynamic behaviour of the wings. Compliance with this directive must be achieved prior to 31 December 1995. This regulation extends across the Commonwealth of Australia, administered by the Civil Aviation Safety Authority, and there are no specified exclusions or exemptions in this particular directive. The application of these regulations can be extended or clarified through subordinate instruments issued by the relevant authorities.

Key Provisions

The Civil Aviation Regulations 1998, specifically Part 39 - 105, contain the Civil Aviation Safety Authority's (CASA) Schedule of Airworthiness Directives, which includes AD/F28/49. This directive applies to all Fokker F28 series aeroplanes with serial numbers (S/Nos) ranging from 11092 to 11231, excluding 11094 to 11110 and 11204 (Section 1). The directive mandates that these aircraft must comply with Fokker SB F28/57-70, and it references Netherlands AD 85-44 for further guidance. Compliance with these directives is crucial as air leakage through the wing butt straps and boundary layer fences can negatively impact the aerodynamic performance of the wings (Section 2). The obligations imposed by AD/F28/49 require operators of the specified Fokker F28 series aircraft to ensure that their planes meet the requirements outlined in Fokker SB F28/57-70. This includes inspecting and, if necessary, repairing or replacing the wing butt straps and boundary layer fences to prevent air leakage. Operators must maintain thorough documentation of any inspections, repairs, or modifications carried out in accordance with this directive (Section 3). Additionally, operators must ensure that all personnel involved in the inspection and maintenance processes are adequately trained and qualified to perform these tasks. Failure to comply with AD/F28/49 can result in significant legal and operational consequences. Under the Civil Aviation Act 1988, non-compliance with an airworthiness directive can be considered an offence. The penalties for such offences can be severe and include substantial fines. For corporate entities, the maximum penalty can reach up to $210,000, while individuals can face fines of up to $42,000 (Section 4). Furthermore, non-compliance may lead to the grounding of affected aircraft, which can result in significant operational disruptions and financial losses for the operator. CASA has the authority to take enforcement actions, including issuing directives for corrective actions or imposing further penalties to ensure compliance with airworthiness standards.