Narrative:

On flight from gai to winchester (va), I was in communication with potomac approach (ADIZ flight plan) on communication #2. After leaving ADIZ and being instructed to 'squawk 1200/frequency change approved,' I turned volume on communication #2 down, but left ATC frequency selected. After landing at winchester and preparing to depart for return flight, I realized radio was still selected for communication #2, and I had made several calls on what I thought was the winchester CTAF (which I had selected on communication #1), but evidently had actually made on the ATC frequency still selected on communication #2. In the future, I intend to normally avoid use of individual communication selection switches and use the switch which automatically selects the receiver based on the position of the transmitter selection, so the frequency I'm listening to is also what I'm set to transmit on. Also will double-check selector before transmitting. I don't know how often this kind of inadvertent interference happens, but especially in ATC -- intensive areas, it might be useful to issue an advisory circular on this topic.

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Original NASA ASRS Text

Title: LOW TIME C177RG PVT PLT XMITS HIS SELF-ANNOUNCE INFO ON THE PCT APCH CTL FREQ WHEN HE HAS NOT RESET HIS COM XMITTER SELECTOR TO THE #1 POS FOR HIS CALL INTO OKV, VA.

Narrative: ON FLT FROM GAI TO WINCHESTER (VA), I WAS IN COM WITH POTOMAC APCH (ADIZ FLT PLAN) ON COM #2. AFTER LEAVING ADIZ AND BEING INSTRUCTED TO 'SQUAWK 1200/FREQ CHANGE APPROVED,' I TURNED VOLUME ON COM #2 DOWN, BUT LEFT ATC FREQ SELECTED. AFTER LNDG AT WINCHESTER AND PREPARING TO DEPART FOR RETURN FLT, I REALIZED RADIO WAS STILL SELECTED FOR COM #2, AND I HAD MADE SEVERAL CALLS ON WHAT I THOUGHT WAS THE WINCHESTER CTAF (WHICH I HAD SELECTED ON COM #1), BUT EVIDENTLY HAD ACTUALLY MADE ON THE ATC FREQ STILL SELECTED ON COM #2. IN THE FUTURE, I INTEND TO NORMALLY AVOID USE OF INDIVIDUAL COM SELECTION SWITCHES AND USE THE SWITCH WHICH AUTOMATICALLY SELECTS THE RECEIVER BASED ON THE POS OF THE XMITTER SELECTION, SO THE FREQ I'M LISTENING TO IS ALSO WHAT I'M SET TO XMIT ON. ALSO WILL DOUBLE-CHK SELECTOR BEFORE XMITTING. I DON'T KNOW HOW OFTEN THIS KIND OF INADVERTENT INTERFERENCE HAPPENS, BUT ESPECIALLY IN ATC -- INTENSIVE AREAS, IT MIGHT BE USEFUL TO ISSUE AN ADVISORY CIRCULAR ON THIS TOPIC.

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.