Narrative:

We were level at FL300 ATC mentioned traffic 1 o'clock at FL310 opposite direction. We looked for and spotted the traffic which I thought was closer. About the same time; I heard the other aircraft; say that he had a resolution advisory to 'descend.' he said he was committed to follow the resolution advisory and descend. My aircraft is not equipped with TCAS. ATC asked us to recycle our transponder as they were not receiving our mode 'C.' ATC also asked if we were level at FL300 as assigned. All 3 altimeters were indicating 30;000 ft. On descent; we were asked to call out every 1;000 ft. After landing I talked to our maintenance supervisor who said that the system was recently checked out; tested and certified for rvsm.

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Original NASA ASRS Text

Title: CE550 Captain at FL300 is informed of opposite direction traffic at FL310. At about the same time the other aircraft states that they are descending for a TCAS RA. The CE550 was not TCAS equipped and remained level and is informed by ATC that Mode C has failed.

Narrative: We were level at FL300 ATC mentioned traffic 1 o'clock at FL310 opposite direction. We looked for and spotted the traffic which I thought was closer. About the same time; I heard the other aircraft; say that he had a Resolution Advisory to 'descend.' He said he was committed to follow the Resolution Advisory and descend. My Aircraft is not equipped with TCAS. ATC asked us to recycle our Transponder as they were not receiving our Mode 'C.' ATC also asked if we were level at FL300 as assigned. All 3 Altimeters were indicating 30;000 FT. On descent; we were asked to call out every 1;000 FT. After landing I talked to our Maintenance Supervisor who said that the system was recently checked out; tested and certified for RVSM.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.