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 CAR 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 F100 (F28 Mk 100) Series Aeroplanes
AD/F100/44 No 1 Pitot Tube AC Sensing Circuit 7/2001
Applicability: All Model F.28 Mk.0070 and Mk.0100 aeroplanes with either Fokker Service Bulletin (SB) F100-30-019 or SB F100-30-020 embodied.
Requirement: 1. Perform an operational check of the No 1 Pitot Tube Heating System, to establish whether both tube and mast heaters are serviceable, in accordance with Part 1 of the Accomplishment Instructions of Fokker SB F100-30-25 Revision 1 dated 14 March 2001.
2. If, as a result of the Requirement 1 operation check, either heating element is found to be inoperative, replace the defective Pitot Tube with a serviceable unit of the same part number.
3. Modify the No 1 Pitot Tube Alternating Current Sensing Circuit in accordance with Part 2, 3, 4, 5 or 6, as applicable, of the Accomplishment Instructions of Fokker SB F100-30-25 Revision 1.
Note: RLD AD 2001-041 (A) refers
Compliance: 1. Within three calendar months after the effective date of this Directive and thereafter at intervals not to exceed 12 months until the Requirement 3 modification is incorporated.
2. Before further flight after the Requirement1 check has been completed.
3. Within three calendar years after the effective date of this Directive.
This Airworthiness Directive becomes effective on 12 July 2001.
Background: The RLD has advised that recently an operator reported the loss of indicated airspeed (IAS) on the captain’s speed indicator during a flight in icing conditions.
Inspection revealed an inoperative No 1 pitot tube heater caused by a short circuit in the heater element. Further investigation revealed that a short circuit in the No 1 pitot tube heaters can stay undetected, due to the characteristics of the DC/AC inverter supplying the AC current to the heater. This condition, if not corrected, may lead to further occurrences of undetected short circuits in the pitot tube heaters, with consequent loss the captain’s air speed indication.
Fokker F100 (F28 Mk 100) Series Aeroplanes
AD/F100/44 (Continued)
This Directive requires repetitive checking of the No 1 pitot tube heaters until modification of the current monitoring circuit is accomplished. The modification is designed to ensure that short circuits of the pitot tube heaters are detected.
Eugene Paul Holzapfel
Delegate of the Civil Aviation Safety Authority 21 May 2001
The above AD is notified in the Commonwealth of Australia Gazette on 13 June 2001.
Overview
The Airworthiness Directive issued under the Civil Aviation Act 1988 (Cth) is designed to address safety issues related to specific aircraft models. In this instance, AD/F100/44 was enacted in 2001 to rectify an unsafe condition discovered in Fokker F100 (F28 Mk 100) Series Aeroplanes, particularly concerning the No 1 Pitot Tube AC Sensing Circuit. The directive was issued by the Civil Aviation Safety Authority (CASA) to ensure the airworthiness of these aircraft. The primary objective of this directive is to prevent the occurrence of short circuits in the No 1 pitot tube heaters, which could lead to the loss of indicated airspeed on the captain’s speed indicator, thereby enhancing flight safety. Compliance with this directive is mandatory for all Model F.28 Mk.0070 and Mk.0100 aeroplanes that incorporate Fokker Service Bulletins SB F100-30-019 or SB F100-30-020.
Scope and Application
The Airworthiness Directive F2006B09646 applies specifically to all Fokker F100 (F28 Mk 100) series aeroplanes that have either Fokker Service Bulletin (SB) F100-30-019 or SB F100-30-020 embodied. This applies to Model F.28 Mk.0070 and Mk.0100 aeroplanes, and the directive mandates certain actions to address an identified unsafe condition related to the No 1 Pitot Tube AC Sensing Circuit. The directive is issued by the Civil Aviation Safety Authority (CASA) delegate, Eugene Paul Holzapfel, under subregulation 39.1 (1) of the Civil Aviation Regulations 1998. The actions required must be carried out in accordance with the specified instructions and within the given timeframes. This AD has a Commonwealth reach, being issued within the framework of Australian federal law, and it becomes effective on 12 July 2001. The directive does not explicitly mention any exclusions or exemptions but focuses on ensuring airspeed indications are reliable and accurate by mandating operational checks and modifications to the No 1 Pitot Tube Alternating Current Sensing Circuit. The AD extends its application through subordinate instruments, ensuring compliance by operators of the specified Fokker F100 series aeroplanes.
Key Provisions
The Airworthiness Directive (AD) F100/44 applies to all Fokker F100 (F28 Mk 100) series aeroplanes, specifically those with Fokker Service Bulletin (SB) F100-30-019 or SB F100-30-020 incorporated (Applicability section). This AD was issued under subregulation 39.1(1) of the Civil Aviation Regulations 1998 by the delegate of the Civil Aviation Safety Authority (CASA), Eugene Paul Holzapfel, on 21 May 2001. The AD became effective on 12 July 2001. The key requirements of the AD are outlined in the Requirement section. These requirements are designed to address an unsafe condition identified in the No 1 Pitot Tube AC Sensing Circuit, which can lead to a loss of indicated airspeed (IAS) on the captain’s speed indicator, particularly in icing conditions.
The requirements set forth in the AD mandate that operators perform an operational check of the No 1 Pitot Tube Heating System to verify the serviceability of both the tube and mast heaters, as per Part 1 of Fokker SB F100-30-25 Revision 1 dated 14 March 2001 (Requirement 1). If the check reveals that either heating element is inoperative, the defective Pitot Tube must be replaced with a serviceable unit of the same part number (Requirement 2). Additionally, operators must modify the No 1 Pitot Tube Alternating Current Sensing Circuit in accordance with Parts 2, 3, 4, 5, or 6 of the Accomplishment Instructions of Fokker SB F100-30-25 Revision 1 (Requirement 3). The AD also references RLD AD 2001-041 (A).
Operators of affected aircraft must comply with specific timelines for the actions outlined in the AD. The operational check must be performed within three calendar months after the effective date of the AD and thereafter at intervals not exceeding 12 months until the modification is incorporated (Compliance 1). The check must be completed before further flight after it has been conducted (Compliance 2). Finally, the modification must be carried out within three calendar years from the effective date of the AD (Compliance 3).
Failure to comply with the AD can result in civil or criminal consequences. The AD does not explicitly state the penalties for non-compliance, but non-compliance with CASA directives generally can lead to enforcement actions, including fines and potential criminal charges for individuals responsible for the oversight of aircraft maintenance. The specific penalties would be determined by the Civil Aviation Safety Authority based on the nature and severity of the non-compliance.