COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Fokker F100 (F28 Mk 100) Series Aeroplanes
AD/F100/33 Wheel-Speed Sensor Wiring 4/99
Applicability: F.28 Mk.0100 aeroplanes listed in Fokker Service Bulletins (SB) F100-32-067 Revision 1 dated 6 July 1998 and F100-32-037 Revision 1 dated 4 December 1998.
Requirement: 1. If not previously accomplished, modify the grounding of the wheel speed sensor wiring shielding in a0cordance with Part 1, 2, 3, or 4, as applicable, of the Accomplishment Instructions of Fokker SB F100-32-067 dated 12 March 1993 or Revision 1 dated 6 July 1998.
2. Install new electrical grounding on the wheel speed sensor channel of the anti-skid control box in accordance with Part 1, 2, or 3, as applicable, of the Accomplishment Instructions of Fokker SB F100-32-037 Revision 2 dated 4 December 1998.
Note: Netherlands AD 1998-100/2 refers.
Compliance: 1. Prior to 1 August 1999.
2. Prior to 15 February 2000.
This Airworthiness Directive becomes effective on 22 April 1999.
Background: The RLD received a report concerning an incident with a F.28 Mk.0100, where during approach, the liftdumpers inadvertently deployed. Preliminary investigation revealed that the outboard wheel speed signal was induced to ‘high’ by electromagnetic interference (EMI). The liftdumper arming test did not detect the signal because it was not transmitted until the skid control box was powered-up on landing gear DOWN selection.
Further analysis by the RLD of the liftdumper system protection against EMI, together with investigation into the Flight Control Computer failure mode which caused the EMI, have shown that aeroplanes with a post SB F100-32-067 configuration are significantly less susceptible to EMI on the wheel speed signals. This directive requires modification of the wheel speed sensor wiring shielding and the installation of new electrical grounding of the anti-skid system to prevent EMI.
The RLD has advised that these modification are considered a partial solution to the problem and that further rulemakeing is anticipated.
Overview
The Civil Aviation Regulations 1998, specifically PART 39 - 105, was enacted to ensure the safety and airworthiness of aircraft in Australia. This legislative instrument is administered by the Civil Aviation Safety Authority (CASA) and aims to mitigate risks associated with air travel. A notable directive within this regulation is AD/F100/33, which pertains to the Fokker F100 (F28 Mk 100) series aeroplanes and was introduced to address an identified gap in the aircraft's electromagnetic interference (EMI) protection systems. The directive mandates modifications to the wheel speed sensor wiring shielding and the installation of new electrical grounding on the anti-skid control box to prevent EMI, which can cause inadvertent deployment of liftdumpers during flight. The directive became effective on 22 April 1999, and compliance was required before 1 August 1999 for certain modifications and before 15 February 2000 for others. The Civil Aviation Safety Authority has indicated that this directive is a partial solution, with further rulemaking anticipated to address the issue comprehensively.
Scope and Application
The Civil Aviation Regulations 1998, under Part 39 - 105, specifically address the airworthiness directives for Fokker F100 (F28 Mk 100) series aeroplanes, with the particular focus on wheel-speed sensor wiring as outlined in AD/F100/33. This regulation applies to Fokker F28 Mk.0100 aeroplanes referenced in Fokker Service Bulletins (SB) F100-32-067 Revision 1 dated 6 July 1998 and F100-32-037 Revision 1 dated 4 December 1998. The directive mandates modifications to the grounding of the wheel speed sensor wiring shielding and the installation of new electrical grounding on the wheel speed sensor channel of the anti-skid control box, to be accomplished in accordance with the relevant parts of the accomplishment instructions specified in the service bulletins. Compliance with these modifications is required prior to specified dates, namely before 1 August 1999 and before 15 February 2000, with the directive becoming effective on 22 April 1999. This regulatory requirement is grounded in the investigation of an incident where electromagnetic interference (EMI) caused inadvertent liftdumper deployment, highlighting the importance of these modifications for the safety of the aircraft.
Key Provisions
The Civil Aviation Regulations 1998, specifically Part 39 - 105, include Airworthiness Directives (AD) for the Fokker F100 (F28 Mk 100) Series Aeroplanes, one of which is AD/F100/33. This directive pertains to the wheel-speed sensor wiring and was issued on 4/99, taking effect on 22 April 1999. The directive applies to F.28 Mk.0100 aeroplanes listed in Fokker Service Bulletins (SB) F100-32-067 Revision 1 dated 6 July 1998 and F100-32-037 Revision 1 dated 4 December 1998. The primary requirement of this directive is twofold: first, it mandates the modification of the grounding of the wheel speed sensor wiring shielding in accordance with the Accomplishment Instructions of Fokker SB F100-32-067 dated 12 March 1993 or Revision 1 dated 6 July 1998; and second, it requires the installation of new electrical grounding on the wheel speed sensor channel of the anti-skid control box as per the Accomplishment Instructions of Fokker SB F100-32-037 Revision 2 dated 4 December 1998. Compliance with these requirements must be achieved by certain dates: the modifications must be completed prior to 1 August 1999, and the installation of new electrical grounding must be accomplished prior to 15 February 2000.
The obligations imposed by AD/F100/33 are clear and specific. Operators of Fokker F100 (F28 Mk 100) Series Aeroplanes must ensure that the specified modifications to the wheel speed sensor wiring shielding are carried out in accordance with the provided instructions. Additionally, they must install new electrical grounding on the wheel speed sensor channel of the anti-skid control box as instructed. These obligations are designed to mitigate the risk of electromagnetic interference (EMI) affecting the wheel speed signals, which could potentially lead to inadvertent deployment of liftdumpers during critical flight phases. The directive underscores the importance of timely compliance to ensure the continued airworthiness of the affected aircraft.
Failure to comply with AD/F100/33 may result in civil or criminal consequences. While the specific penalties are not detailed within the directive itself, non-compliance with Civil Aviation Regulations 1998 can generally lead to enforcement actions by the Civil Aviation Safety Authority (CASA). These actions may include fines, legal proceedings, or other regulatory measures. The severity of the penalties can vary depending on the nature and extent of the non-compliance, with potential maximum penalties including substantial fines and, in serious cases, imprisonment for individuals responsible for ensuring compliance. It is therefore imperative for operators to adhere to the requirements set forth in the directive to avoid these adverse consequences.