Narrative:

My safety pilot and I experienced an intermittent loss of ATC reception while practicing night IFR approachs in a radar vectoring environment. The first indication was the safety pilot's complete loss of transmit and receive capability with me via the intercom. Once he gave up trying to re- establish service, the safety pilot disconnected his headset, and coincidentally he warned me of conflicting traffic and recommended a climb to avoid it. While distracted by the communication and traffic problems we were unaware that ATC reception must have been affected too, because when clear of traffic, I told ATC I'd had no advisory from them, and they replied they had been trying to reach us for the past 5 mi. Thinking that the safety pilot's headset had caused the reception loss and believing that its disconnection had cleared the fault, we initiated a practice approach under ATC direction. As we neared the final approach course I noted that we had heard no recent voice traffic on frequency so I called to ask if they were still with us, and the controller replied he'd been trying to reach us for 3 mi. I realized that the nature of the communication problems still eluded us, so I canceled IFR and said I'd go home VFR. The controller asked me to stay with him as he wished to steer us out of the air traffic area, and he gave us a vector over the top of the localizer. Shortly, I realized I'd lost reception again. No amount of switch flipping, knob twisting or calling ATC restored the link this time, so I squawked 7600 and proceeded as earlier directed. As we approached the localizer the safety pilot again warned of traffic, and this time initiated a right 360 degree turn. Unsure of what concerned him I completed the turn and advised ATC of what we were up to, still with no reception from them. I continued to seek avionics settings that would restore communication, and suddenly was able to hear ATC over the cabin speaker though still not through the headset (xmissions were never affected during the whole ordeal, thankfully). I was given TRACON's phone number after landing, and had a friendly conversation with the supervisor in which he assured me he was just concerned that we were 'all right' mentally, no doubt. We haven't yet fathomed the technical problem afflicting the avionics, but the issue of concern to the ASRS, I think, is the coordination of light plane dual pilot operation. Last yr when my safety pilot was practicing approachs and I was riding shotgun, I observed an imminent traffic conflict, called 'my airplane' on the intercom, and took the necessary evasive action. In the above incident, however, the safety pilot merely advised me of the conflict, forcing me to come out from under the hood, locate the traffic, plan an evasion, and execute it myself. I told the safety pilot that process wasted precious time and I preferred him to take command in such critical cases. When later we were leaving the air traffic area, since his headset was inoperative he was unaware that I was under ATC direction, and perhaps not conscious that our situation had changed to VFR. So he assumed control when he perceived an apparent traffic conflict, as I'd asked him to do, even though it was inappropriate in our VFR environment. No danger to any aircraft resulted from this incident, ATC was informed of our situation and intentions via our xmissions, even if we could hear them, and they seemed satisfied that we'd made the best of an evolving equipment problem. But the difficulty is worth recalling because of the evident breakdown of cockpit coordination between my safety pilot and me. The FAA conducts valuable pilot seminars on such topics as WX and use of the ATC system (eg, operation rainchk) and I would recommend a new one on light plane dual pilot coordination. It would be of great value to us who don't normally operate in dual pilot sits to learn what the airlines and their controllers have to teach us about better cockpit coordination.

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Original NASA ASRS Text

Title: INTERMITTENT LOSS OF COM FREQ.

Narrative: MY SAFETY PLT AND I EXPERIENCED AN INTERMITTENT LOSS OF ATC RECEPTION WHILE PRACTICING NIGHT IFR APCHS IN A RADAR VECTORING ENVIRONMENT. THE FIRST INDICATION WAS THE SAFETY PLT'S COMPLETE LOSS OF XMIT AND RECEIVE CAPABILITY WITH ME VIA THE INTERCOM. ONCE HE GAVE UP TRYING TO RE- ESTABLISH SVC, THE SAFETY PLT DISCONNECTED HIS HEADSET, AND COINCIDENTALLY HE WARNED ME OF CONFLICTING TFC AND RECOMMENDED A CLB TO AVOID IT. WHILE DISTRACTED BY THE COM AND TFC PROBS WE WERE UNAWARE THAT ATC RECEPTION MUST HAVE BEEN AFFECTED TOO, BECAUSE WHEN CLR OF TFC, I TOLD ATC I'D HAD NO ADVISORY FROM THEM, AND THEY REPLIED THEY HAD BEEN TRYING TO REACH US FOR THE PAST 5 MI. THINKING THAT THE SAFETY PLT'S HEADSET HAD CAUSED THE RECEPTION LOSS AND BELIEVING THAT ITS DISCONNECTION HAD CLRED THE FAULT, WE INITIATED A PRACTICE APCH UNDER ATC DIRECTION. AS WE NEARED THE FINAL APCH COURSE I NOTED THAT WE HAD HEARD NO RECENT VOICE TFC ON FREQ SO I CALLED TO ASK IF THEY WERE STILL WITH US, AND THE CTLR REPLIED HE'D BEEN TRYING TO REACH US FOR 3 MI. I REALIZED THAT THE NATURE OF THE COM PROBS STILL ELUDED US, SO I CANCELED IFR AND SAID I'D GO HOME VFR. THE CTLR ASKED ME TO STAY WITH HIM AS HE WISHED TO STEER US OUT OF THE ATA, AND HE GAVE US A VECTOR OVER THE TOP OF THE LOC. SHORTLY, I REALIZED I'D LOST RECEPTION AGAIN. NO AMOUNT OF SWITCH FLIPPING, KNOB TWISTING OR CALLING ATC RESTORED THE LINK THIS TIME, SO I SQUAWKED 7600 AND PROCEEDED AS EARLIER DIRECTED. AS WE APCHED THE LOC THE SAFETY PLT AGAIN WARNED OF TFC, AND THIS TIME INITIATED A R 360 DEG TURN. UNSURE OF WHAT CONCERNED HIM I COMPLETED THE TURN AND ADVISED ATC OF WHAT WE WERE UP TO, STILL WITH NO RECEPTION FROM THEM. I CONTINUED TO SEEK AVIONICS SETTINGS THAT WOULD RESTORE COM, AND SUDDENLY WAS ABLE TO HEAR ATC OVER THE CABIN SPEAKER THOUGH STILL NOT THROUGH THE HEADSET (XMISSIONS WERE NEVER AFFECTED DURING THE WHOLE ORDEAL, THANKFULLY). I WAS GIVEN TRACON'S PHONE NUMBER AFTER LNDG, AND HAD A FRIENDLY CONVERSATION WITH THE SUPVR IN WHICH HE ASSURED ME HE WAS JUST CONCERNED THAT WE WERE 'ALL RIGHT' MENTALLY, NO DOUBT. WE HAVEN'T YET FATHOMED THE TECHNICAL PROB AFFLICTING THE AVIONICS, BUT THE ISSUE OF CONCERN TO THE ASRS, I THINK, IS THE COORD OF LIGHT PLANE DUAL PLT OP. LAST YR WHEN MY SAFETY PLT WAS PRACTICING APCHS AND I WAS RIDING SHOTGUN, I OBSERVED AN IMMINENT TFC CONFLICT, CALLED 'MY AIRPLANE' ON THE INTERCOM, AND TOOK THE NECESSARY EVASIVE ACTION. IN THE ABOVE INCIDENT, HOWEVER, THE SAFETY PLT MERELY ADVISED ME OF THE CONFLICT, FORCING ME TO COME OUT FROM UNDER THE HOOD, LOCATE THE TFC, PLAN AN EVASION, AND EXECUTE IT MYSELF. I TOLD THE SAFETY PLT THAT PROCESS WASTED PRECIOUS TIME AND I PREFERRED HIM TO TAKE COMMAND IN SUCH CRITICAL CASES. WHEN LATER WE WERE LEAVING THE ATA, SINCE HIS HEADSET WAS INOP HE WAS UNAWARE THAT I WAS UNDER ATC DIRECTION, AND PERHAPS NOT CONSCIOUS THAT OUR SIT HAD CHANGED TO VFR. SO HE ASSUMED CTL WHEN HE PERCEIVED AN APPARENT TFC CONFLICT, AS I'D ASKED HIM TO DO, EVEN THOUGH IT WAS INAPPROPRIATE IN OUR VFR ENVIRONMENT. NO DANGER TO ANY ACFT RESULTED FROM THIS INCIDENT, ATC WAS INFORMED OF OUR SIT AND INTENTIONS VIA OUR XMISSIONS, EVEN IF WE COULD HEAR THEM, AND THEY SEEMED SATISFIED THAT WE'D MADE THE BEST OF AN EVOLVING EQUIP PROB. BUT THE DIFFICULTY IS WORTH RECALLING BECAUSE OF THE EVIDENT BREAKDOWN OF COCKPIT COORD BTWN MY SAFETY PLT AND ME. THE FAA CONDUCTS VALUABLE PLT SEMINARS ON SUCH TOPICS AS WX AND USE OF THE ATC SYS (EG, OP RAINCHK) AND I WOULD RECOMMEND A NEW ONE ON LIGHT PLANE DUAL PLT COORD. IT WOULD BE OF GREAT VALUE TO US WHO DON'T NORMALLY OPERATE IN DUAL PLT SITS TO LEARN WHAT THE AIRLINES AND THEIR CTLRS HAVE TO TEACH US ABOUT BETTER COCKPIT COORD.

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.