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Published: 23 September 2011
Effective: 23 September 2011

ATA Chapter: 34

Subject:

Microair Avionics T2000SFL Transponders

Applicability:

All maintainers and operators of Microair Avionics T2000SFL Transponders.

Applicability:           

All maintainers and operators of Microair Avionics T2000SFL Transponders.

Purpose:      

This Continuing Airworthiness Notice (CAN) is issued to highlight the potential problems associated with Microair Avionics T2000SFL Transponders embodied with software prior to revision 8.
Transponders prior to revision 7 may generate intermittent replies to interrogations from Mode S Secondary Surveillance Radar (SSR), or stop replying and default to a non-reply mode. Furthermore, Microair Avionics have advised that the QNH compensation in software prior to revision 8 work backwards. In 2010 Microair Avionics released new firmware at revision 8 which corrected the QNH compensation.

Background:          

The CAA is aware of incidents with certain T2000SFL Transponders where intermittent or complete loss of detection has been experienced in New Zealand by Mode S SSR interrogators. The CAA has received reports that the QNH compensation in some T2000SFL Transponders work backwards. A safe navigation environment in transponder mandatory airspace relies on accurate and reliable surveillance information transmitted by Mode S transponders. Incorrect of missing transponder data can result in increased controller and/or flight crew work load which may develop into a hazardous situation.
With the Australia Airservices plan to roll out Mode S SSR interrogators in Australia, CASA issued Airworthiness Bulletin (AWB) 34-010 issue 1, dated 17 September 2007.

Recommendation:

For the reasons described above the CAA strongly recommends maintainers and operators upgrade Microair Avionics T2000SFL Transponders to revision 8 or later to correct the potential problems identified in this CAN. For further advice on T2000SFL Transponders upgrade options Microair Avionics can be contacted at info@microair.com.au

The following documents provide further information about the contents of this CAN:

Furthermore, if you become aware, or are notified of a transponder deficiency affecting your aircraft, the CAA recommends that you initiate an unscheduled maintenance action to correct any deficiencies.