Narrative:

Air carrier was on IFR flight plan descending into redmond, or, air carrier Y had been issued clearance through FSS for departure. Air carrier X reported the airport in sight and was informed there would be a delay for issuance of visual approach clearance due to traffic with departure clearance. Air carrier X cancelled IFR and continued descent with VFR flight following. This is standard procedure at rdm when WX permits. The pilot of air carrier Y did not check on frequency when expected so I called to see if he was there. There was no reply. The inbound aircraft reported that he could hear the other aircraft (same airline as the departing aircraft) calling on advisory frequency and that he was taxiing. The inbound aircraft was descending through 074 and I would be losing him on radar out of 065. I told the inbound to change to advisory frequency as I now believed the departure was either still on the ground or just departing and he would be able to get an accurate position through advisory. As the inbound was replying to the frequency change, the target of the departure aircraft appeared directly in front of and 200 ft below the inbound. I tried to call the inbound, but he'd already left frequency. The targets merged at the same altitude. The aircraft the pilot had heard taxiing was another aircraft calling FSS for clearance. FSS had not yet called center so we did not know he was on advisory frequency. It is normal for pilots to check on at about 5000-5500 ft on departure. The departing pilot did not check on until 075 and said he had not seen the air carrier X.

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Original NASA ASRS Text

Title: ACR Y HAD POSSIBLE NMAC WITH ACR X. SEE AND AVOID CONCEPT.

Narrative: ACR WAS ON IFR FLT PLAN DSNDING INTO REDMOND, OR, ACR Y HAD BEEN ISSUED CLRNC THROUGH FSS FOR DEP. ACR X RPTED THE ARPT IN SIGHT AND WAS INFORMED THERE WOULD BE A DELAY FOR ISSUANCE OF VISUAL APCH CLRNC DUE TO TFC WITH DEP CLRNC. ACR X CANCELLED IFR AND CONTINUED DSCNT WITH VFR FLT FOLLOWING. THIS IS STANDARD PROC AT RDM WHEN WX PERMITS. THE PLT OF ACR Y DID NOT CHK ON FREQ WHEN EXPECTED SO I CALLED TO SEE IF HE WAS THERE. THERE WAS NO REPLY. THE INBOUND ACFT RPTED THAT HE COULD HEAR THE OTHER ACFT (SAME AIRLINE AS THE DEPARTING ACFT) CALLING ON ADVISORY FREQ AND THAT HE WAS TAXIING. THE INBOUND ACFT WAS DSNDING THROUGH 074 AND I WOULD BE LOSING HIM ON RADAR OUT OF 065. I TOLD THE INBOUND TO CHANGE TO ADVISORY FREQ AS I NOW BELIEVED THE DEP WAS EITHER STILL ON THE GND OR JUST DEPARTING AND HE WOULD BE ABLE TO GET AN ACCURATE POS THROUGH ADVISORY. AS THE INBOUND WAS REPLYING TO THE FREQ CHANGE, THE TARGET OF THE DEP ACFT APPEARED DIRECTLY IN FRONT OF AND 200 FT BELOW THE INBOUND. I TRIED TO CALL THE INBOUND, BUT HE'D ALREADY LEFT FREQ. THE TARGETS MERGED AT THE SAME ALT. THE ACFT THE PLT HAD HEARD TAXIING WAS ANOTHER ACFT CALLING FSS FOR CLRNC. FSS HAD NOT YET CALLED CENTER SO WE DID NOT KNOW HE WAS ON ADVISORY FREQ. IT IS NORMAL FOR PLTS TO CHK ON AT ABOUT 5000-5500 FT ON DEP. THE DEPARTING PLT DID NOT CHK ON UNTIL 075 AND SAID HE HAD NOT SEEN THE ACR X.

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.