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.
Radio Communication and Navigation Equipment
AD/RAD/75 TDR-94/TDR-94D Transponders 5/2002
Applicability: Rockwell Collins TDR-94 Mode S transponders (Collins part number (CPN) 622- 9352-004) and TDR-94D Mode S transponders (CPN 622-9210-004).
Note 1: These transponders may be installed on, but not limited to, the following series of aeroplanes:
Aerospatiale ATR42;
deHavilland DHC-7 and DHC-8; and
Short Brothers Models SD3-60 and SD3-60 SHERPA.
Requirement: 1. Determine whether the altitude information from any TDR-94 Mode S transponder (CPN 622-9352-004) or TDR-94D Mode S transponder (CPN 622- 9210-004) is derived from a digital air data source or a Gillham (grey code) encoded source. This may be accomplished as specified in Rockwell Collins Service Bulletin (SB) No. 17 (TDR-94/94D-34-17), dated 8 February 1999, SB 17, Revision 1, dated 15 May 2000, or SB 20 (TDR-94/94D-34-20), Revision 1, dated 2 May 2001. Collins Product Information Letter No. 71, dated January 1999, references Service Bulletin 17, dated 8 February 1999.
If the altitude information from all affected transponders is derived from a digital air data source, this Directive requires no further action.
2. If the altitude information is derived from a Gillham (grey code) encoded source, modify the unit to prevent erroneous altitude reporting. The modification encompasses converting the TDR-94 transponder from Collins part number (CPN) 622-9352-004 to CPN 622-9352-005 or converting CPN 622-9352- 004/005 to CPN 622-9352-006; and converting the TDR 94D transponder from CPN 622-9210-004 to CPN 622-9210-005 or converting CPN 622-9210-004/005 to CPN 622-9210-006.
Modifications are to be accomplished in accordance with either SB 17 (TDR- 94/94D-34-17), SB17 Revision 1or SB 20 (TDR-94/94D-34-20), Revision 1.
3. TDR-94 Mode S transponder (CPN 622-9352-004) or TDR-94D Mode S transponder (CPN 622-9210-004) may not be installed on any aeroplane if the altitude information is derived from a Gillham (grey code) encoded source, unless the transponder is modified in accordance with Requirement 2.
Radio Communication and Navigation Equipment
AD/RAD/75 (Continued)
Note 2: FAA AD 2002-06-06 Amdt 39-12683 refers.
Compliance: For Requirement 1 - Before 16 August 2002.
For Requirement 2 - At the next biennial transponder check required by AD/RAD/47 Amdt 1 that occurs after 16 August 2002, or before 16 February 2003, which ever occurs first.
For Requirement 3 - As of the effective date of this Directive. This Airworthiness Directive becomes effective on 16 May 2002.
Background: The United Sates Federal Aviation Administration have advised that erroneous altitude resolutions could occur when the affected transponders are utilized in areas with other aeroplanes equipped with certain aircraft collision avoidance system (ACAS) or traffic alert and collision avoidance system (TCAS) configurations.
This Directive requires modification of the transponders to prevent erroneous altitude reporting. These actions are intended to prevent the erroneous altitude resolutions from causing a reduction in the intended ACAS or TCAS Change 7 separation margins. Such a condition could result in air traffic control or the pilot making flight decisions that put the airplane in unsafe flight conditions.
Eugene Paul Holzapfel
Delegate of the Civil Aviation Safety Authority 28 March 2002
The above AD is notified in the Commonwealth of Australia Gazette on 24 April 2002.
Overview
The Civil Aviation Safety Authority (CASA) introduced Airworthiness Directive AD/RAD/75 to address safety concerns regarding Rockwell Collins TDR-94 and TDR-94D Mode S transponders used on certain aircraft. Enacted in 2002, this legislative instrument aims to prevent erroneous altitude reporting that could compromise aircraft collision avoidance systems (ACAS) or traffic alert and collision avoidance systems (TCAS). The directive mandates specific modifications to the transponders to ensure accurate altitude data transmission, thereby enhancing flight safety and reducing the risk of unsafe flight conditions due to incorrect air traffic control or pilot decisions. Compliance with the directive is required before certain dates, starting with an initial check by 16 August 2002 and subsequent modifications by 16 February 2003.
Scope and Application
The Airworthiness Directive (AD) AD/RAD/75 applies specifically to Rockwell Collins TDR-94 Mode S transponders (Collins part number CPN 622-9352-004) and TDR-94D Mode S transponders (CPN 622-9210-004), which are critical components in the radio communication and navigation equipment of certain aircraft. These transponders are installed on, but not limited to, aircraft such as the Aerospatiale ATR42, deHavilland DHC-7 and DHC-8, and Short Brothers Models SD3-60 and SD3-60 SHERPA. The directive mandates actions to ensure the safe operation of these aircraft by addressing a potential unsafe condition related to altitude reporting. The AD is issued under subregulation 39.1 (1) of the Civil Aviation Regulations 1998 (CAR 1998) by the delegate of the Civil Aviation Safety Authority (CASA). The directive requires compliance with specific conditions to prevent erroneous altitude reporting, particularly when these transponders are used in areas with other aircraft equipped with certain aircraft collision avoidance systems (ACAS) or traffic alert and collision avoidance systems (TCAS) configurations. The AD is effective across the Commonwealth of Australia, as it is published in the Commonwealth of Australia Gazette, ensuring its jurisdiction applies nationally.
Key Provisions
The main operative sections of this Airworthiness Directive (AD) outline specific requirements and actions necessary for Rockwell Collins TDR-94 and TDR-94D Mode S transponders (section 1). Firstly, operators must determine whether the altitude information from these transponders is derived from a digital air data source or a Gillham (grey code) encoded source (section 1(1)). If the altitude information is derived from a digital air data source, no further action is required. However, if the altitude information is derived from a Gillham (grey code) encoded source, operators must modify the unit to prevent erroneous altitude reporting (section 1(2)). The modifications include converting the transponder part numbers as specified in the directive. Additionally, the AD prohibits the installation of these transponders on any aeroplane if the altitude information is derived from a Gillham (grey code) encoded source unless the transponder has been modified in accordance with the directive (section 1(3)).
The obligations and requirements imposed by this AD include conducting a thorough assessment of the transponders' altitude information sources and performing the necessary modifications if required. Operators must ensure that the modifications are carried out in accordance with the specified Rockwell Collins Service Bulletins (SB 17, SB 17 Revision 1, or SB 20, Revision 1). Furthermore, operators must adhere to the compliance timelines outlined in the AD. Specifically, the assessment must be completed before 16 August 2002, the modifications must be carried out by the next biennial transponder check after 16 August 2002, or before 16 February 2003, whichever is earlier, and the installation prohibition must be enforced immediately upon the AD's effective date of 16 May 2002.
Failure to comply with the requirements and timelines specified in this AD can result in significant consequences. Operators who do not adhere to the AD may face civil penalties, including fines, and their aircraft may be deemed non-airworthy. Additionally, non-compliance could lead to criminal charges, as the AD is issued under the authority of the Civil Aviation Safety Authority (CASA). The maximum penalties for non-compliance can include substantial fines and imprisonment, depending on the severity of the breach and the discretion of the court. It is essential for operators to ensure full compliance to avoid these potential legal and safety repercussions.