AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CASR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
Fokker F50 (F27 Mk 50) Series Aeroplanes
AD/F50/86 Skid Control Unit 11/2003
Applicability: Model F.27 Mk050, Mk.0502 and Mk.0604 aeroplanes, all serial numbers, equipped with Aircraft Braking Systems Corporation (ABSC) skid control units with Part Numbers (P/N) 6004125 or 6004125-1.
Requirement: 1. Replace skid control units P/N 6004125 or 6004125-1 with P/N 6004125-2 units in accordance with Part 2 Accomplishment Instructions of Fokker Services Service Bulletin (SB) F50-32-038 dated 8 May 2003.
Note 1: P/N 6004125 units are pre ABSC SB F50-32-4 and 6004125-1 units are post ABSC SB F50-32-4.
Note 2: For modification of the skid control units refer to ABSC SB 6004125-32-01 dated 7 May 200.
2. Modify the skid control unit ground wiring in accordance with Part 2 Accomplishment Instructions of Fokker Services SB F50-32-035 dated 2 August 1999.
3. Skid control units P/N 6004125 or 6004125-1 may not be installed on any aeroplane as a replacement part.
Note 3: CAA(NL) BLA 2003-091 (A) refers.
Compliance: For Requirement 1:
Aeroplanes with skid control unit P/N 6004125 - Before 30 June 2004.
Aeroplanes with skid control unit P/N 6004125-1 - Before 30 December 2004.
For Requirement 2 - Before or concurrent with Requirement 1. For Requirement 3 - After 30 June 2004.
This Airworthiness Directive becomes effective on 30 October 2003.
Fokker F50 (F27 Mk 50) Series Aeroplanes
AD/F50/86 (continued)
Background: Several Fokker 50 (F.27 Mk.050) operators have reported pulsating brake behaviour and loss of braking at low speeds in the normal braking mode. Investigation of this phenomenon has shown that electromagnetic interference (EMI), resulting from failed components in other electronic systems and induced on the wheel speed sensor and/or test inputs of the skid control unit, is the cause of these problems. ABSC, the skid control unit manufacturer, has now developed a modified unit that corrects these problems.
This Directive requires the replacement of the affected skid control units with modified units and at the same time requires new ground (earth) connections for the skid control units.
Jim Coyne
Delegate of the Civil Aviation Safety Authority 19 September 2003
The above AD is notified in the Commonwealth of Australia Gazette on 8 October 2003.
Overview
The Airworthiness Directive F2006B09916, issued by the Civil Aviation Safety Authority (CASA) in 2003, addresses a safety concern identified in Fokker F50 (F.27 Mk 50) series aeroplanes equipped with specific skid control units. The directive aims to correct unsafe conditions caused by electromagnetic interference (EMI) that can lead to pulsating brake behaviour and loss of braking at low speeds. By requiring the replacement of affected skid control units and modifying the ground wiring, the directive seeks to ensure the continued airworthiness of the affected aircraft models. The policy objective is to enhance aviation safety by mitigating the risk of EMI-related braking failures, thereby protecting passengers, crew, and ground personnel.
Scope and Application
The Airworthiness Directive (AD) issued under subregulation 39.1(1) of the Civil Aviation Safety Regulations 1998 applies specifically to Fokker F50 (F.27 Mk.050) series aeroplanes, including all serial numbers, that are equipped with skid control units manufactured by Aircraft Braking Systems Corporation (ABSC) with Part Numbers (P/N) 6004125 or 6004125-1. This directive mandates the replacement and modification of these skid control units to address safety concerns related to electromagnetic interference causing pulsating brake behaviour and loss of braking at low speeds. The requirement necessitates that the affected skid control units be replaced with P/N 6004125-2 units, with modifications to the skid control unit ground wiring, and prohibits the installation of P/N 6004125 or 6004125-1 units as replacements. Compliance with these requirements is mandated within specific timeframes, with certain actions required before 30 June 2004 and others before 30 December 2004. This AD is applicable nationally within the Commonwealth of Australia and was published in the Commonwealth of Australia Gazette on 8 October 2003.
Key Provisions
This Airworthiness Directive (AD) applies specifically to Fokker F50 (F.27 Mk.050) Series aeroplanes, including those with serial numbers, that are equipped with Aircraft Braking Systems Corporation (ABSC) skid control units bearing part numbers 6004125 or 6004125-1 (section 1). The directive mandates that these units must be replaced with part number 6004125-2 units, following the instructions provided in Part 2 Accomplishment Instructions of Fokker Services Service Bulletin (SB) F50-32-038 dated 8 May 2003 (section 1). Additionally, the ground wiring of the skid control unit must be modified in accordance with Part 2 Accomplishment Instructions of Fokker Services SB F50-32-035 dated 2 August 1999 (section 2). It is also stipulated that skid control units with part numbers 6004125 or 6004125-1 may not be installed on any aeroplane as a replacement part (section 3). Compliance with these requirements must be achieved by specific dates, with the replacement of the skid control units needing to be completed by 30 June 2004 for units with part number 6004125 and by 30 December 2004 for units with part number 6004125-1 (section 4). The modification of the skid control unit ground wiring must occur before or concurrently with the replacement of the units, and the prohibition on the installation of the older skid control units as replacement parts must be observed after 30 June 2004 (section 4).
Under this AD, the entities governed by it are required to ensure that the specified modifications to the skid control units and their wiring are carried out as per the instructions provided in the referenced service bulletins. This involves replacing the existing skid control units with the new model, modifying the ground wiring as instructed, and ensuring that the older skid control units are not used as replacements. Failure to comply with these requirements could result in the aircraft not meeting the necessary airworthiness standards, which could potentially lead to safety issues such as the pulsating brake behaviour and loss of braking at low speeds that the directive aims to correct.
Breaching the requirements set forth in this AD could lead to significant consequences, as the directive is issued to address a safety issue that could affect the airworthiness of the aircraft. While the AD does not explicitly state penalties or consequences for non-compliance, it is clear that failure to adhere to the directive could result in the aeroplane not meeting the necessary safety standards. This could potentially lead to enforcement actions by the Civil Aviation Safety Authority (CASA), including the possibility of grounding the aircraft until the required modifications are completed. The safety of the aircraft and its passengers is paramount, and non-compliance with airworthiness directives can have serious implications, including potential legal action and penalties under aviation law.