Narrative:

Received aircraft, B737-300 with #1 transponder MEL'ed inoperative, #2 working normally. I flew several flts with the #2 transponder without incident. A few days later, another captain told me that I and others might be in violation because the #1 transponder controls the TCASII system. With #1 transponder out, the TCASII doesn't operate. The question becomes, does the TCASII also have to be put on the MEL. The MEL book for air carrier X is unclr. The TCASII in fact is not inoperative, and even if it was, you can go without it if you put the little yellow sticker on it. Seems silly doesn't it.

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Original NASA ASRS Text

Title: CAPT OF A B737-300 WAS INCORRECTLY INFORMED BY ANOTHER COMPANY CAPT THAT THE TCASII EQUIP DOES NOT OPERATE WHEN THE #1 XPONDER IS INOP. THE #2 XPONDER WAS WORKING AND THE MEL ACFT LOG ENTRY DID NOT INDICATE THE TCASII EQUIP WAS NOT WORKING. HE SUBSEQUENTLY LEARNED THAT IF THE TCASII WAS NOT WORKING, IT WOULD ALSO BE MEL'ED, A YELLOW TAG PLACED ON IT.

Narrative: RECEIVED ACFT, B737-300 WITH #1 XPONDER MEL'ED INOP, #2 WORKING NORMALLY. I FLEW SEVERAL FLTS WITH THE #2 XPONDER WITHOUT INCIDENT. A FEW DAYS LATER, ANOTHER CAPT TOLD ME THAT I AND OTHERS MIGHT BE IN VIOLATION BECAUSE THE #1 XPONDER CTLS THE TCASII SYS. WITH #1 XPONDER OUT, THE TCASII DOESN'T OPERATE. THE QUESTION BECOMES, DOES THE TCASII ALSO HAVE TO BE PUT ON THE MEL. THE MEL BOOK FOR ACR X IS UNCLR. THE TCASII IN FACT IS NOT INOP, AND EVEN IF IT WAS, YOU CAN GO WITHOUT IT IF YOU PUT THE LITTLE YELLOW STICKER ON IT. SEEMS SILLY DOESN'T IT.

Data retrieved from NASA's ASRS site as of July 2007 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.