Narrative:

We departed ase en route to phx. We were on the 4TH leg of the day which started at XA15 from our base at ptk and had us returning to ptk at roughly PM00. After being handed off to ZDV while flying the lindz 3 departure, ZDV cleared us direct to jnc, climb and maintain FL230, and advised that we would have traffic at our 12 O'clock position and (I don't recall the mileage). He said that we would be given a higher altitude when clear of the traffic. I heard the PNF read back, 'roger direct grand junction and climb and maintain FL230.' the traffic was not visible on the TCASII prior to the turn or during the climb. I had my scale set at 20 mi. Shortly after leveling off at FL230, the traffic appeared at roughly 11:30 O'clock position and 15 mi on the TCASII unit. I thought this odd and doublechked the altitude preselect window which showed FL230. I stated to the PNF that this wasn't good and that I was going to climb because the traffic had now turned yellow on the TCASII. At this point, ZDV called us asking our altitude. PNF replied FL230, at which time ZDV directed us to climb to FL240. As I initiated the climb, the TCASII gave us an RA indicating roughly a 1500 FPM rate of climb. After about 500 ft of climb the RA cleared. I spotted the traffic passing our left side at our 10 O'clock position, roughly 3-5 mi and at least 1000 ft below us. I don't recall ZDV giving the other aircraft a descent. I am not sure of the type of the other aircraft, it appeared rather small, possibly a commuter. The question arose as to which altitude we were cleared to, when the next sector controller advised us that ZDV wanted us to call regarding the incident. The PIC, who was the PNF, called and was told that we had only been cleared to FL220. He explained to them that he had heard and read back FL230. They told him that they had listened to the tape which was garbled during his readback and that the only numbers they could understand on the altitude readback were the two and the zero. The middle number was garbled. The supervisor indicated that they would review the incident. It would appear that we had a miscom. I was flying and it was just prior to dusk. The sky was clear and the sun was directly in our eyes. I was busy flying and trying to block the sun so that I could see the instruments, when we received the clearance to climb. I didn't hear all of the clearance, but did hear the PNF read back the clearance to proceed direct to grand junction and to climb to FL230, which he then set in the altitude preselect window and I acknowledged. Unfortunately I have no suggestions for corrective actions. I think we were using sound crew management and division of duties. While I don't recall feeling tired, fatigue and distraction with the sun. It could have been a factor on our part, if in fact the controller had cleared us to FL220 and we mistook it for FL230. Supplemental information from acn 465590: we received a TA and then an RA. The PF climbed and turned right responding to the RA. I called ZDV responding to the RA. ZDV asked what altitude we were climbing to. We were then cleared to FL240. Subsequent airborne telephone call with ZDV 30 mins later indicated confusion from the tapes as to altitude assignment given and acknowledged. I am grateful that both aircraft had functional TCASII equipment and thereby avoided a potentially serious incident. The climb rate of our aircraft from FL210-FL230 was not excessive (approximately 1500 FPM) and we were level for a short period of time before the RA occurred. I feel there was sufficient time to alert us if we had a wrong altitude assignment.

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Original NASA ASRS Text

Title: A CPR G1159 TURBOPROP CLBS TO ASSIGNED ALT OF FL230 AND RECEIVES A TCASII FROM SAME ALT, OPPOSITE DIRECTION TFC 40 MI SW OF JNC, CO.

Narrative: WE DEPARTED ASE ENRTE TO PHX. WE WERE ON THE 4TH LEG OF THE DAY WHICH STARTED AT XA15 FROM OUR BASE AT PTK AND HAD US RETURNING TO PTK AT ROUGHLY PM00. AFTER BEING HANDED OFF TO ZDV WHILE FLYING THE LINDZ 3 DEP, ZDV CLRED US DIRECT TO JNC, CLB AND MAINTAIN FL230, AND ADVISED THAT WE WOULD HAVE TFC AT OUR 12 O'CLOCK POS AND (I DON'T RECALL THE MILEAGE). HE SAID THAT WE WOULD BE GIVEN A HIGHER ALT WHEN CLR OF THE TFC. I HEARD THE PNF READ BACK, 'ROGER DIRECT GRAND JUNCTION AND CLB AND MAINTAIN FL230.' THE TFC WAS NOT VISIBLE ON THE TCASII PRIOR TO THE TURN OR DURING THE CLB. I HAD MY SCALE SET AT 20 MI. SHORTLY AFTER LEVELING OFF AT FL230, THE TFC APPEARED AT ROUGHLY 11:30 O'CLOCK POS AND 15 MI ON THE TCASII UNIT. I THOUGHT THIS ODD AND DOUBLECHKED THE ALT PRESELECT WINDOW WHICH SHOWED FL230. I STATED TO THE PNF THAT THIS WASN'T GOOD AND THAT I WAS GOING TO CLB BECAUSE THE TFC HAD NOW TURNED YELLOW ON THE TCASII. AT THIS POINT, ZDV CALLED US ASKING OUR ALT. PNF REPLIED FL230, AT WHICH TIME ZDV DIRECTED US TO CLB TO FL240. AS I INITIATED THE CLB, THE TCASII GAVE US AN RA INDICATING ROUGHLY A 1500 FPM RATE OF CLB. AFTER ABOUT 500 FT OF CLB THE RA CLRED. I SPOTTED THE TFC PASSING OUR L SIDE AT OUR 10 O'CLOCK POS, ROUGHLY 3-5 MI AND AT LEAST 1000 FT BELOW US. I DON'T RECALL ZDV GIVING THE OTHER ACFT A DSCNT. I AM NOT SURE OF THE TYPE OF THE OTHER ACFT, IT APPEARED RATHER SMALL, POSSIBLY A COMMUTER. THE QUESTION AROSE AS TO WHICH ALT WE WERE CLRED TO, WHEN THE NEXT SECTOR CTLR ADVISED US THAT ZDV WANTED US TO CALL REGARDING THE INCIDENT. THE PIC, WHO WAS THE PNF, CALLED AND WAS TOLD THAT WE HAD ONLY BEEN CLRED TO FL220. HE EXPLAINED TO THEM THAT HE HAD HEARD AND READ BACK FL230. THEY TOLD HIM THAT THEY HAD LISTENED TO THE TAPE WHICH WAS GARBLED DURING HIS READBACK AND THAT THE ONLY NUMBERS THEY COULD UNDERSTAND ON THE ALT READBACK WERE THE TWO AND THE ZERO. THE MIDDLE NUMBER WAS GARBLED. THE SUPVR INDICATED THAT THEY WOULD REVIEW THE INCIDENT. IT WOULD APPEAR THAT WE HAD A MISCOM. I WAS FLYING AND IT WAS JUST PRIOR TO DUSK. THE SKY WAS CLR AND THE SUN WAS DIRECTLY IN OUR EYES. I WAS BUSY FLYING AND TRYING TO BLOCK THE SUN SO THAT I COULD SEE THE INSTS, WHEN WE RECEIVED THE CLRNC TO CLB. I DIDN'T HEAR ALL OF THE CLRNC, BUT DID HEAR THE PNF READ BACK THE CLRNC TO PROCEED DIRECT TO GRAND JUNCTION AND TO CLB TO FL230, WHICH HE THEN SET IN THE ALT PRESELECT WINDOW AND I ACKNOWLEDGED. UNFORTUNATELY I HAVE NO SUGGESTIONS FOR CORRECTIVE ACTIONS. I THINK WE WERE USING SOUND CREW MGMNT AND DIVISION OF DUTIES. WHILE I DON'T RECALL FEELING TIRED, FATIGUE AND DISTR WITH THE SUN. IT COULD HAVE BEEN A FACTOR ON OUR PART, IF IN FACT THE CTLR HAD CLRED US TO FL220 AND WE MISTOOK IT FOR FL230. SUPPLEMENTAL INFO FROM ACN 465590: WE RECEIVED A TA AND THEN AN RA. THE PF CLBED AND TURNED R RESPONDING TO THE RA. I CALLED ZDV RESPONDING TO THE RA. ZDV ASKED WHAT ALT WE WERE CLBING TO. WE WERE THEN CLRED TO FL240. SUBSEQUENT AIRBORNE TELEPHONE CALL WITH ZDV 30 MINS LATER INDICATED CONFUSION FROM THE TAPES AS TO ALT ASSIGNMENT GIVEN AND ACKNOWLEDGED. I AM GRATEFUL THAT BOTH ACFT HAD FUNCTIONAL TCASII EQUIP AND THEREBY AVOIDED A POTENTIALLY SERIOUS INCIDENT. THE CLB RATE OF OUR ACFT FROM FL210-FL230 WAS NOT EXCESSIVE (APPROX 1500 FPM) AND WE WERE LEVEL FOR A SHORT PERIOD OF TIME BEFORE THE RA OCCURRED. I FEEL THERE WAS SUFFICIENT TIME TO ALERT US IF WE HAD A WRONG ALT ASSIGNMENT.

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.