AD/RAD/92 Amdt 1 Rockwell Collins TDR-94/94D Transponder/Honeywell AZ800/810 Air Data Computer Selected Altitude Data Inputs (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/RAD/92 and issues the following AD under subregulation 39.001(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

Radio Communication and Navigation Equipment

AD/RAD/92
Amdt 1 Rockwell Collins TDR-94/94D Transponder/Honeywell AZ800/810 Air Data Computer Selected Altitude Data Inputs 20/2010

Applicability:	Rockwell Collins Mode S Transponders identified by type and Part Number (P/N) in Table 1 when installed in an aeroplane equipped with Honeywell AZ800 or AZ810 (all part numbers) air data computers (ADC) where the data bus interface between the Honeywell ADC and the Rockwell Collins transponder is providing the Selected Altitude data input to the transponder.
Table 1 - Transponders identified by Type and P/N
Type		P/N (all serial numbers)
TDR-94		622-9352-007, 622-9352-008 and 622-9352-108
TDR-94D		622-9210-007, 622-9210-008 and 622-9210-108
Note 1:  These transponder/ADC combinations are known to be installed on, but not limited to, the following aeroplanes:
Manufacturer			Model
Avions de Transport Régional			ATR 42 and ATR 72 series
Bombardier (formerly Canadair)			CL-600-2A12 (601 Variant), CL-600-2B16 (601-3A and 601-3R Variants)
Bombardier (formerly de Havilland Canada)			DHC-8, Series 100, 200 and 300, all models
Dassault Aviation			Mystère-Falcon 900 series
Gulfstream			G-IV
Requirement:	1.    Either:
a.     Modify the transponder in accordance with the applicable Rockwell Collins Service Bulletin (SB) listed in Table 2 and Table 3 and modify the aeroplane in accordance with an approved aeroplane modification.
or
b.    Replace the transponder, with a TDR-94 unit identified by P/N 622-9352-309 or -409, or a TDR-94D unit identified by P/N 622-9210-309 or -409, as applicable in accordance with an approved aeroplane modification.
Table 2 - TDR-94 Transponders
Current P/N	New P/N(options)			Rockwell Collins Service Bulletin (SB) instructions to be used for modification
622-9352-007	622-9352-309			TDR-94/94D-34-506
	622-9352-409			TDR-94/94D-34-507
622-9352-008	622-9352-309			TDR-94/94D-34-505
	622-9352-409			TDR-94/94D-34-507
622-9352-108	622-9352-409			TDR-94/94D-34-505
Table 3 - TDR-94D Transponders
Current P/N	New P/N (options)			Rockwell Collins SB instructions to be used for modification
622-9210-007	622-9210-309			TDR-94/94D-34-506
	622-9210-409			TDR-94/94D-34-507
622-9210-008	622-9210-309			TDR-94/94D-34-505
	622-9210-409			TDR-94/94D-34-507
622-9210-108	622-9210-409			TDR-94/94D-34-505
2.    Disable the Automatic Dependent Surveillance - Broadcast (ADS-B) function on TDR-94 transponders with P/N 622-9352-409 and TDR-94D transponders with P/N 622-9210-409 unless compliance with European Aviation Safety Agency (EASA) AMC 20-24 or Section 9B of CAO 20.8 has been demonstrated.

3.    Transponders, identified by Applicability Statement may not be installed as a replacement spare in an aeroplane equipped with Honeywell AZ800 or AZ810 (all part numbers) ADC where the data bus interface between the Honeywell ADC and the transponder is providing the Selected Altitude data input to the transponder unless modified in accordance with Requirement 1.a.
Note 2:  This Directive is not applicable to ATR-42 and ATR-72 aeroplanes on which the affected transponder and ADC installation has been done in accordance with an ATR design definition, although equipped with transponders and Honeywell AZ800 or AZ810 ADC as listed in the Applicability section of this Directive, since on these aeroplanes’ original architecture, the Selected Altitude is not provided by the ADC.
Note 3:  This Directive is not applicable to DHC-8 Series 100, 200 and 300 aeroplanes, all models, on which the affected transponder and ADC installation has been done in accordance with the applicable Bombardier Type Design definition, although equipped with affected transponders and Honeywell AZ800 or AZ810 ADC as listed in the Applicability section of this Directive, are exempt from having to meet the requirements of this Directive, since on these aeroplanes’ original architecture, the Selected Altitude is not provided by the ADC.  This exemption does not apply to aeroplanes that have been modified to enable a digital link between the air data computer and the transponder.
Note 4:  EASA AD 2009-0173R1 refers.
Compliance:	For Requirement 1 - Remains unchanged as ‘Within 12 months after the effective date of the original issue of this Directive.
For Requirement 2 - Concurrent with accomplishment of the Requirement 1 modification of the aeroplane.
For Requirement 3 - After modification of the aeroplane in accordance with Requirement 1.
This Amendment becomes effective on 25 October 2010.
Background:	The original issue of this Directive advised of a mismatch between the ARINC (formerly Aeronautical Radio Inc.) and General Aviation Manufacturers Association (GAMA) specifications for the Selected Altitude in Motion Bit of label 102 in certain Rockwell Collins TDR-94 transponders is causing incorrect transmission of the Mode-S Selected Altitude parameter.
This condition, if not corrected, could lead to invalid Selected Altitude data being transmitted to Mode S ground stations, creating disruptions in the Air Traffic Management process and potentially compromising aeroplane safety.

For the reasons described above, the original issue of this Directive required the modification or replacement of the affected transponders and prohibited reinstallation of unmodified units.  This Amendment continues those requirements and at the same time supplies relief from those requirements for operators of some DHC-8 aircraft.

The original issue of this Directive became effective on 26 March 2010.

Mike Higgins
Delegate of the Civil Aviation Safety Authority

5 October 2010