All operators and maintainers of aircraft fitted with Rockwell Collins TPR 901 Mode S Transponders.
This Continuing Airworthiness Notice (CAN) is issued to highlight potential problems associated with Rockwell Collins TPR 901 Mode S Transponders P/N 822-1338-003.
These transponders are known to be installed on, but not limited to aircraft modified per FAA STC ST01202WI-D, or modified per STC EASA.IM.A.00392 (European validation of the FAA STC).
The CAA is aware that certain Rockwell Collins TPR 901 Mode S Transponders P/N 822-1338-003 may be transmitting incorrect aircraft identification data, while other transponders may be interfacing incorrectly with airport ground tracking systems. Incorrect or missing transponder data can result in increased controller and/or flight crew work load which may develop into a hazardous situation.
Rockwell Collins issued SB 15 to introduce modification instructions to correct the aircraft identification data transmission problem, but this modification inadvertently introduced a new problem which affected the transponder interface with airport ground tracking systems. Rockwell Collins subsequently issued SB 16 to modify the transponder back to the pre-SB 15 configuration, which inadvertently re-introduced the aircraft identification transmission problem. Rockwell Collins then issued SB 503 to introduce modification instructions and P/N 822-1338-005 which corrects the aircraft identification data transmission problem.
EASA issued Safety Information Bulletin (SIB) 2011-20 dated 15 July 2011 recommending operators/maintainers of affected transponders comply with the modification instructions in Rockwell Collins SB 503.
For the reasons described above the CAA recommends that operators and maintainers of aircraft fitted with Rockwell Collins TPR 901 Mode S Transponders P/N 822-1338-003 comply with the instructions in Rockwell Collins SB 503.
Rockwell Collins SIL 11-1 provides an Approved Model List (AML) for STC ST01202WI-D.
A copy of EASA SIB No: 2011-20 can be obtained from: http://ad.easa.europa.eu/search/advanced/(external link)
