AD/RAD/93 Rockwell Collins TDR-94/94D Transponders Aircraft Type Category (Cth)

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 39.001(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/93 Rockwell Collins TDR-94/94D
Transponders - Aircraft Type Category 6/2010

Applicability:	Rockwell Collins Mode S Transponders identified by type and Part Number (P/N) in Table 1 when installed in aeroplanes featuring weight-on-wheels input to the transponder.
Table 1
Type	P/N (all serial numbers)
TDR-94	622-9352-008, 622-9352-108, 622-9352-308 and 622-9352-408
TDR-94D	622-9210-008, 622-9210-108, 622-9210-308 and 622-9210-408
Note 1:  These transponders 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 Aerospace (formerly Canadair)			CL-600-2B16 (604 Variant) CL-600-2B19 (RJ100 and RJ200)
Cessna Aircraft Company			525 (CJ1) Serial Numbers (S/N) 525-0600 through to 525-0684 525A (CJ2) S/N 525A-0300 through 525A-0438 525B (CJ3) S/N 525B-0001 through 525B-0293 560 (Citation Encore+) S/N 560-0751 through 560-0802 560XL (Citation XLS+) S/N 560-6001 and up
Dassault Aviation			Mystère-Falcon 50 Mystère-Falcon 900 Falcon 900EX Falcon 2000 Falcon 2000EX
Piaggio Aero Industries			P.180 (Avanti and Avanti II)
SAAB			2000
Note 2:  Aeroplanes which are operated at take-off rotation speeds not exceeding 100 knots are not affected by the Requirements of this Directive.
Requirement:	1.    Verify that the Aircraft Type Mode Strapping code is set to ‘0’ (zero) or ‘1’, as defined in Rockwell-Collins Service Letter TDR-94(  ) SIL 07-2 (document reference 523-0810069-001000) dated 27 September 2007.  If the Aircraft Type Mode Strapping code is set to either 0 or 1, no further action is required.
2.    If the Aircraft Type Mode Strapping code is set to any other value than 0 or 1, modify the aeroplane by setting the transponder Aircraft Type Mode strapping code to ‘0’, removing all connections to P1-20, P1-21 and P1-22 as specified in TDR-94(  ) SIL 07-2, in accordance with approved aeroplane modification instructions.
Note 3:  Aircraft Type Mode strapping code = 0 corresponds to P1-20, P1-21 and P1-22 discrete inputs not connected (not grounded).  Aircraft Type Mode strapping code = 1 corresponds to P1-20 being connected to ground and P1-21 and P1-22 discrete inputs not connected.
Note 4:  This directive is not applicable to aeroplanes that have complied with the following Service Bulletins (SB) or have had the following modifications incorporated:
a.    Dassault aeroplanes, if modified in-service or during production in accordance with the instructions of Dassault Aviation, as applicable to aeroplane model and identified in Table 2.
Table 2
Aeroplane Model		Service Bulletin		Modification(s)
Mystère-Falcon 50		F50-457		M2966 and M2968
Mystère-Falcon 900		F900-354		M3896
Falcon 900EX		F900EX-239		M3896
Falcon 2000		F2000-312		M2624 and M2632
Falcon 2000EX		F2000EX-043		M2624
b.    ATR 42 and ATR 72 aeroplanes, which have P/N 622-9210-108 transponders installed in accordance with ATR modification 05614 during production, or in accordance with ATR SB ATR42-34-0167 or ATR72-34-1094 in-service, as applicable to aeroplane model, whilst in service.

c.     SAAB 2000 aeroplanes, which have P/N 622-9210-008 transponders installed in accordance with SAAB modifications 6231, 6243 and 6249 during production, or in accordance with SAAB SB 2000-34-066, 2000-34-072 and 2000-34-076 whilst in service.
d.    Bombardier (Canadair) CL-600-2B16 (604 Variant) aeroplanes, if modified, prior to the effective date of this Directive, in accordance with the requirements of European Aviation Safety Agency (EASA) Airworthiness Directive 2007-0120 (this Directive was not issued as an Australian AD and refers to Bombardier SB 604-34-54).
e.     Bombardier CL-600-2B19 (RJ100 and RJ200) aeroplanes which have P/N 622-9210-008 transponders installed in accordance with Bombardier Aerospace Modification TC601R16789 during production or in accordance with Bombardier Aerospace SB 601R-34-142 (Mod TC601R16790) whilst in-service.
f.     Cessna Model 525, 525A and 525B aeroplanes which have P/N 622-9352-008 transponders installed in accordance with Cessna Engineering Change Records (ECRs) 55298, 58654 and 59567 during production, and Model 525B aeroplanes which have P/N 622-9352-008 transponders installed whilst in-service in accordance with Cessna Service Bulletin SB525B-34-03 or SB525B-34-08.
g.    Cessna Model 525, 525A, 525B, 560 and 560XL aeroplanes which have P/N 622-9210-008 transponders installed in accordance with Cessna ECRs 55298, 58654, 59567, 56135 and 58032 during production, and Model 525B aeroplanes which have P/N 622-9210-008 transponders installed whilst in-service in accordance with Cessna Service Bulletin SB525B-34-03 or SB525B-34-08.
h.    Piaggio P.180 (Avanti) aeroplanes which have P/N 622-9210-008 transponders installed in accordance with Piaggio modification 80-0773 during production or whilst in-service in accordance with Piaggio SB-80-0227.
i.     Piaggio P.180 (Avanti II) aeroplanes which have P/N 622-9210-008 transponders installed in accordance with Piaggio modifications 80-0588 and 80-0598 during production.
Note 5:  EASA AD 2010-0003R1 refers.
Compliance:	For Requirements 1 and 2 - Within twelve calendar months after the effective date of this Directive.
This Airworthiness Directive becomes effective on 26 March 2010.

Background:	The EASA issued AD 2007-0120, applicable to Bombardier (Canadair) CL-600-2B16 (604 Variant) aeroplanes, which required the accomplishment of interim measures to prevent loss of detection of the aeroplane by Secondary Surveillance Radars (SSR) that do not process Mode A/C signals (ie Mode S only), caused by an anomaly in the Rockwell-Collins TDR94/94D Mode S Transponder.
Further analysis by Rockwell Collins has shown that the problem was caused by an error in the air/ground override logic of the transponders.  The analysis also revealed that the problem may exist in more aeroplanes than the single type to which AD 2007-0120 applies.
This condition, if not corrected, could lead to further incidents of loss of aeroplane detection by SSR stations that do not process Mode A/C signals.  Therefore, this Directive, which is based on EASA AD 2010-0003R1, requires a check of the setting of the transponder’s Aircraft Type Mode Strapping and an aeroplane wiring change if an incorrect setting is found.

Mike Higgins
Delegate of the Civil Aviation Safety Authority

15 March 2010