Narrative:

Flight was an rvsm/gmu test flight from spi to irk and return to spi. On board crew, 2 pilots, avionics technician and our a&P. We were conducting the required data collection for the rvsm installation certification. This had to be collected in the rvsm altitude spectrum. The collection was carried out at FL310 and FL290. During the climb the technician had come to the cockpit to confirm the test parameters. This occurred around FL190 to FL200 in the climb. While he was telling us what he needed for the data collection, we received a transmission from ZKC telling us to climb to and maintain FL220 for overtaking traffic at FL230. The right seat pilot says he acknowledged the transmission and set the altitude alerter for FL220. Then he turned to listen to the avionics technician. I had turned my head slightly to the right in order to hear the technician who was not on a headset. What I heard was 'maintain --230.' I reset the altitude command/alerter for FL230 and the aircraft continued the climb to and leveloff at FL230. The right seat pilot had turned enough that he didn't immediately see the erroneous setting. When he turned back, he immediately saw the error and said we were only cleared to FL220. I stated that we had been told to maintain FL230. We immediately checked the TCASII and noted that there was traffic at our 6 O'clock position just inside the 10 NM range (the unit was set on 10 NM range). I determined that I was in error and disconnected the autoplt to begin a descent back to FL220. At this time center called telling us to descend to FL220 and we did. No radio calls were missed, misunderstood or misinterped either before or after this one incident. The test flight was successfully completed and the aircraft returned to spi. Ok, what happened to cause me to miss portions of one radio call and only that one? My opinion is that when I turned my head slightly to the right in order to hear the technician's instructions, the cord of my sony light weight headset drug on the back of the seat just enough to cause the left ear piece to turn slightly and momentarily block the sound. This was not accompanied by any form of warning such as static, electrical snaps, pops or clicks. My right ear piece was out of my right ear so that I could hear what the technician was saying. I have noticed that when placing the headset on my head if the ear pieces are cocked, even slightly, I would experience a temporary loss of sound. I believe that this is what happened and caused me to miss critical portions of the center's transmission in this instance. While the procedure for changing the altitude command/alert setting that I have used for 19 yrs with this company has worked without prior incident or problem, we found a weakness. In order to prevent this from ever happening again we have changed our procedure so as to add an additional level of mutual concurrence. What this means is that both pilots agree what the new setting should be before it is acknowledged. Then we agree again before and after the altitude command/alert setting was changed to comply with the controling agency's instructions. I have changed my personal procedure regarding the use of my sony headset. I will turn on the overhead speaker and then take off the sony headset when I need to talk to someone that is not on a headset.

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Original NASA ASRS Text

Title: ALT EXCURSION BY A CPR TEST FLT CREW WHEN PIC, PF, MISSETS THE ALT ALERTER AFTER THE FO HAD SET IT CORRECTLY, CLBING TO FL230 VERSUS FL220, 60 NM E OF IRK.

Narrative: FLT WAS AN RVSM/GMU TEST FLT FROM SPI TO IRK AND RETURN TO SPI. ON BOARD CREW, 2 PLTS, AVIONICS TECHNICIAN AND OUR A&P. WE WERE CONDUCTING THE REQUIRED DATA COLLECTION FOR THE RVSM INSTALLATION CERTIFICATION. THIS HAD TO BE COLLECTED IN THE RVSM ALT SPECTRUM. THE COLLECTION WAS CARRIED OUT AT FL310 AND FL290. DURING THE CLB THE TECHNICIAN HAD COME TO THE COCKPIT TO CONFIRM THE TEST PARAMETERS. THIS OCCURRED AROUND FL190 TO FL200 IN THE CLB. WHILE HE WAS TELLING US WHAT HE NEEDED FOR THE DATA COLLECTION, WE RECEIVED A XMISSION FROM ZKC TELLING US TO CLB TO AND MAINTAIN FL220 FOR OVERTAKING TFC AT FL230. THE R SEAT PLT SAYS HE ACKNOWLEDGED THE XMISSION AND SET THE ALT ALERTER FOR FL220. THEN HE TURNED TO LISTEN TO THE AVIONICS TECHNICIAN. I HAD TURNED MY HEAD SLIGHTLY TO THE R IN ORDER TO HEAR THE TECHNICIAN WHO WAS NOT ON A HEADSET. WHAT I HEARD WAS 'MAINTAIN --230.' I RESET THE ALT COMMAND/ALERTER FOR FL230 AND THE ACFT CONTINUED THE CLB TO AND LEVELOFF AT FL230. THE R SEAT PLT HAD TURNED ENOUGH THAT HE DIDN'T IMMEDIATELY SEE THE ERRONEOUS SETTING. WHEN HE TURNED BACK, HE IMMEDIATELY SAW THE ERROR AND SAID WE WERE ONLY CLRED TO FL220. I STATED THAT WE HAD BEEN TOLD TO MAINTAIN FL230. WE IMMEDIATELY CHKED THE TCASII AND NOTED THAT THERE WAS TFC AT OUR 6 O'CLOCK POS JUST INSIDE THE 10 NM RANGE (THE UNIT WAS SET ON 10 NM RANGE). I DETERMINED THAT I WAS IN ERROR AND DISCONNECTED THE AUTOPLT TO BEGIN A DSCNT BACK TO FL220. AT THIS TIME CTR CALLED TELLING US TO DSND TO FL220 AND WE DID. NO RADIO CALLS WERE MISSED, MISUNDERSTOOD OR MISINTERPED EITHER BEFORE OR AFTER THIS ONE INCIDENT. THE TEST FLT WAS SUCCESSFULLY COMPLETED AND THE ACFT RETURNED TO SPI. OK, WHAT HAPPENED TO CAUSE ME TO MISS PORTIONS OF ONE RADIO CALL AND ONLY THAT ONE? MY OPINION IS THAT WHEN I TURNED MY HEAD SLIGHTLY TO THE R IN ORDER TO HEAR THE TECHNICIAN'S INSTRUCTIONS, THE CORD OF MY SONY LIGHT WT HEADSET DRUG ON THE BACK OF THE SEAT JUST ENOUGH TO CAUSE THE L EAR PIECE TO TURN SLIGHTLY AND MOMENTARILY BLOCK THE SOUND. THIS WAS NOT ACCOMPANIED BY ANY FORM OF WARNING SUCH AS STATIC, ELECTRICAL SNAPS, POPS OR CLICKS. MY R EAR PIECE WAS OUT OF MY R EAR SO THAT I COULD HEAR WHAT THE TECHNICIAN WAS SAYING. I HAVE NOTICED THAT WHEN PLACING THE HEADSET ON MY HEAD IF THE EAR PIECES ARE COCKED, EVEN SLIGHTLY, I WOULD EXPERIENCE A TEMPORARY LOSS OF SOUND. I BELIEVE THAT THIS IS WHAT HAPPENED AND CAUSED ME TO MISS CRITICAL PORTIONS OF THE CTR'S XMISSION IN THIS INSTANCE. WHILE THE PROC FOR CHANGING THE ALT COMMAND/ALERT SETTING THAT I HAVE USED FOR 19 YRS WITH THIS COMPANY HAS WORKED WITHOUT PRIOR INCIDENT OR PROB, WE FOUND A WEAKNESS. IN ORDER TO PREVENT THIS FROM EVER HAPPENING AGAIN WE HAVE CHANGED OUR PROC SO AS TO ADD AN ADDITIONAL LEVEL OF MUTUAL CONCURRENCE. WHAT THIS MEANS IS THAT BOTH PLTS AGREE WHAT THE NEW SETTING SHOULD BE BEFORE IT IS ACKNOWLEDGED. THEN WE AGREE AGAIN BEFORE AND AFTER THE ALT COMMAND/ALERT SETTING WAS CHANGED TO COMPLY WITH THE CTLING AGENCY'S INSTRUCTIONS. I HAVE CHANGED MY PERSONAL PROC REGARDING THE USE OF MY SONY HEADSET. I WILL TURN ON THE OVERHEAD SPEAKER AND THEN TAKE OFF THE SONY HEADSET WHEN I NEED TO TALK TO SOMEONE THAT IS NOT ON A HEADSET.

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.