Narrative:

Small aircraft Y was on a full NDB 29 approach at orh, when the controller believed that he had reported the NDB inbound. Later on, there was air carrier X for the full NDB 29 approach. When air carrier X was over the airport at 4000', he was given approach clearance for the NDB 29. The controller was informed by orh tower that small aircraft Y was still outside the NDB. At this time, the controller informed the tower to cancel Y's approach clearance and turn him south off of the approach. Once aircraft Y came on the controller's frequency, he ensured that Y was southbound off of the approach. Then receiving the report from air carrier X that he was turning inbound, air carrier X was switched to the tower frequency. This situation happened in a non radar environment in which the controller should have ensured the position of the first aircraft before the second aircraft was given approach clearance. Supplemental information from acn 132807: the WX was a broken cloud layer at I believe about 2000', with good visibility. Approaching from the west, we had been cleared direct to the crow hill NDB at 3000'. We could see the airport thorough the broken cloud layer as we approached it. We were over the airport when we were cleared for the NDB runway 29 approach. About the time we crossed over the crow hill NDB outbnd, the controller told us there was small aircraft Y in the vicinity swbnd at 2500'. The captain was flying. He remained at 3000' as we looked for the traffic. Small aircraft Y soon passed below us. Small aircraft Y was inbound to crow hill NDB on the same approach at the same time we were crossing the NDB outbnd. The MDA on that segment is 2500', and had we descending, a conflict may have occurred. I believe there had been some confusion between the controller and aircraft Y on his last report as to whether he was at crow hill inbound or outbound. Supplemental information from acn 132172: I told the first officer to ask as to the exact location of the traffic, and meanwhile elected to stay at 3000'. Shortly thereafter, while still outbnd in the procedure turn, I acquired the traffic visually, coming head-on at 2500'. Upon landing at orh, I informed approach control, through the tower, that I would call them upon my return to detroit to discuss the situation. Upon calling from dtw, I found that an ATC supervisor was waiting to talk to me. He said the strips had been pulled and that a preliminary investigation was already underway because something 'had gone wrong.'

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Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN ACR AND SMA. OPERATIONAL ERROR.

Narrative: SMA Y WAS ON A FULL NDB 29 APCH AT ORH, WHEN THE CTLR BELIEVED THAT HE HAD RPTED THE NDB INBND. LATER ON, THERE WAS ACR X FOR THE FULL NDB 29 APCH. WHEN ACR X WAS OVER THE ARPT AT 4000', HE WAS GIVEN APCH CLRNC FOR THE NDB 29. THE CTLR WAS INFORMED BY ORH TWR THAT SMA Y WAS STILL OUTSIDE THE NDB. AT THIS TIME, THE CTLR INFORMED THE TWR TO CANCEL Y'S APCH CLRNC AND TURN HIM S OFF OF THE APCH. ONCE ACFT Y CAME ON THE CTLR'S FREQ, HE ENSURED THAT Y WAS SBND OFF OF THE APCH. THEN RECEIVING THE RPT FROM ACR X THAT HE WAS TURNING INBND, ACR X WAS SWITCHED TO THE TWR FREQ. THIS SITUATION HAPPENED IN A NON RADAR ENVIRONMENT IN WHICH THE CTLR SHOULD HAVE ENSURED THE POS OF THE FIRST ACFT BEFORE THE SECOND ACFT WAS GIVEN APCH CLRNC. SUPPLEMENTAL INFO FROM ACN 132807: THE WX WAS A BROKEN CLOUD LAYER AT I BELIEVE ABOUT 2000', WITH GOOD VISIBILITY. APCHING FROM THE W, WE HAD BEEN CLRED DIRECT TO THE CROW HILL NDB AT 3000'. WE COULD SEE THE ARPT THOROUGH THE BROKEN CLOUD LAYER AS WE APCHED IT. WE WERE OVER THE ARPT WHEN WE WERE CLRED FOR THE NDB RWY 29 APCH. ABOUT THE TIME WE CROSSED OVER THE CROW HILL NDB OUTBND, THE CTLR TOLD US THERE WAS SMA Y IN THE VICINITY SWBND AT 2500'. THE CAPT WAS FLYING. HE REMAINED AT 3000' AS WE LOOKED FOR THE TFC. SMA Y SOON PASSED BELOW US. SMA Y WAS INBND TO CROW HILL NDB ON THE SAME APCH AT THE SAME TIME WE WERE XING THE NDB OUTBND. THE MDA ON THAT SEGMENT IS 2500', AND HAD WE DSNDING, A CONFLICT MAY HAVE OCCURRED. I BELIEVE THERE HAD BEEN SOME CONFUSION BTWN THE CTLR AND ACFT Y ON HIS LAST RPT AS TO WHETHER HE WAS AT CROW HILL INBND OR OUTBOUND. SUPPLEMENTAL INFO FROM ACN 132172: I TOLD THE F/O TO ASK AS TO THE EXACT LOCATION OF THE TFC, AND MEANWHILE ELECTED TO STAY AT 3000'. SHORTLY THEREAFTER, WHILE STILL OUTBND IN THE PROC TURN, I ACQUIRED THE TFC VISUALLY, COMING HEAD-ON AT 2500'. UPON LNDG AT ORH, I INFORMED APCH CTL, THROUGH THE TWR, THAT I WOULD CALL THEM UPON MY RETURN TO DETROIT TO DISCUSS THE SITUATION. UPON CALLING FROM DTW, I FOUND THAT AN ATC SUPVR WAS WAITING TO TALK TO ME. HE SAID THE STRIPS HAD BEEN PULLED AND THAT A PRELIMINARY INVESTIGATION WAS ALREADY UNDERWAY BECAUSE SOMETHING 'HAD GONE WRONG.'

Data retrieved from NASA's ASRS site as of August 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.