Narrative:

I was working sector 27, denver ARTCC, radar position. I took a handoff from denver approach control's south departure controller on air carrier X, an air carrier en route to dfw airport. Air carrier X checked on frequency at 10000. Since letter of agreement between denver approach control and denver center specifies that aircraft will be climbing to FL200 (top altitude of denver approach) or lower if field below FL200, I queried the pilot as to whether he had clearance above 10000. He indicated that he had not been cleared above 10000 and no coordination from denver south departure had been received indicating that the aircraft had been stopped. Air carrier X was still requesting an altitude much higher. At this point, I requested my assistant to query denver south departure as to whether air carrier X was my control to climb or why had been stopped. Scanning the area near air carrier X revealed a slow moving sbound aircraft target in close proximity, approximately at air carrier X's 11 O'clock and less than 5 mi distance diminishing rapidly, altitude indicating 11000. Flight plan information indicated that the aircraft was an small aircraft Y, en route via V81 (an airway that underlies J17, the route of air carrier X) at 11000. Colorado springs approach control adjoins denver south departure at 14000 and below. Small aircraft Y would be controled tower en route only. That's when I jumped on the line to colorado springs approach control and requested whether they had received coordination reference air carrier X. They replied negative, at which time I initiated a pointout to them approximately 5 NM north of their boundary with denver south departure. Unfortunately, radar coverage for colorado springs approach is marginal in that area and the colorado springs approach controller was unable to identify small aircraft Y at 10000 in a timely manner to advise me that denver south departure, apparently previously unaware that air carrier X had been left at 10000 gave us control for climb above that altitude. The small aircraft Y was still in his airspace at 10000 a distance of less than 3 NM from the air carrier X. Had I climbed the air carrier X above 10000 per the denver south departure controller's release for climb at that moment an operational error would have certainly occurred and possibly an accident. Since air carrier X and small aircraft Y had been cleared via essentially the same route (J17 and V81 respectively). Denver to colorado springs is a popular IFR and VFR route and there were several targets in the vicinity of air carrier X. I fortunately detected the limited data block of small aircraft Y prior to attempting to climb air carrier X. Realizing that denver south departure had totally ignored required coordination with colorado springs approach control, I remained on the line with colorado springs approach advising them of air carrier X's specific position and altitude, routing and the fact he was requesting higher altitude but that I thought it unsafe to climb him reference the small aircraft Y who would've been talking to colorado springs approach by that time. Colorado springs approach finally idented air carrier X and agreed to work air carrier X through their airspace.

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Original NASA ASRS Text

Title: TRACON ARTCC TRACON INTERFAC COORD. NON COMPLIANCE WITH LETTER OF AGREEMENT CAUSED POTENTIAL LTSS BTWN ACR X AND SMA Y.

Narrative: I WAS WORKING SECTOR 27, DENVER ARTCC, RADAR POS. I TOOK A HDOF FROM DENVER APCH CTL'S S DEP CTLR ON ACR X, AN AIR CARRIER ENRTE TO DFW ARPT. ACR X CHKED ON FREQ AT 10000. SINCE LETTER OF AGREEMENT BTWN DENVER APCH CTL AND DENVER CENTER SPECIFIES THAT ACFT WILL BE CLBING TO FL200 (TOP ALT OF DENVER APCH) OR LOWER IF FIELD BELOW FL200, I QUERIED THE PLT AS TO WHETHER HE HAD CLRNC ABOVE 10000. HE INDICATED THAT HE HAD NOT BEEN CLRED ABOVE 10000 AND NO COORD FROM DENVER S DEP HAD BEEN RECEIVED INDICATING THAT THE ACFT HAD BEEN STOPPED. ACR X WAS STILL REQUESTING AN ALT MUCH HIGHER. AT THIS POINT, I REQUESTED MY ASSISTANT TO QUERY DENVER S DEP AS TO WHETHER ACR X WAS MY CTL TO CLB OR WHY HAD BEEN STOPPED. SCANNING THE AREA NEAR ACR X REVEALED A SLOW MOVING SBOUND ACFT TARGET IN CLOSE PROX, APPROX AT ACR X'S 11 O'CLOCK AND LESS THAN 5 MI DISTANCE DIMINISHING RAPIDLY, ALT INDICATING 11000. FLT PLAN INFO INDICATED THAT THE ACFT WAS AN SMA Y, ENRTE VIA V81 (AN AIRWAY THAT UNDERLIES J17, THE RTE OF ACR X) AT 11000. COLORADO SPRINGS APCH CTL ADJOINS DENVER S DEP AT 14000 AND BELOW. SMA Y WOULD BE CTLED TWR ENRTE ONLY. THAT'S WHEN I JUMPED ON THE LINE TO COLORADO SPRINGS APCH CTL AND REQUESTED WHETHER THEY HAD RECEIVED COORD REFERENCE ACR X. THEY REPLIED NEGATIVE, AT WHICH TIME I INITIATED A POINTOUT TO THEM APPROX 5 NM N OF THEIR BOUNDARY WITH DENVER S DEP. UNFORTUNATELY, RADAR COVERAGE FOR COLORADO SPRINGS APCH IS MARGINAL IN THAT AREA AND THE COLORADO SPRINGS APCH CTLR WAS UNABLE TO IDENTIFY SMA Y AT 10000 IN A TIMELY MANNER TO ADVISE ME THAT DENVER S DEP, APPARENTLY PREVIOUSLY UNAWARE THAT ACR X HAD BEEN LEFT AT 10000 GAVE US CTL FOR CLB ABOVE THAT ALT. THE SMA Y WAS STILL IN HIS AIRSPACE AT 10000 A DISTANCE OF LESS THAN 3 NM FROM THE ACR X. HAD I CLBED THE ACR X ABOVE 10000 PER THE DENVER S DEP CTLR'S RELEASE FOR CLB AT THAT MOMENT AN OPERROR WOULD HAVE CERTAINLY OCCURRED AND POSSIBLY AN ACCIDENT. SINCE ACR X AND SMA Y HAD BEEN CLRED VIA ESSENTIALLY THE SAME RTE (J17 AND V81 RESPECTIVELY). DENVER TO COLORADO SPRINGS IS A POPULAR IFR AND VFR RTE AND THERE WERE SEVERAL TARGETS IN THE VICINITY OF ACR X. I FORTUNATELY DETECTED THE LIMITED DATA BLOCK OF SMA Y PRIOR TO ATTEMPTING TO CLB ACR X. REALIZING THAT DENVER S DEP HAD TOTALLY IGNORED REQUIRED COORD WITH COLORADO SPRINGS APCH CTL, I REMAINED ON THE LINE WITH COLORADO SPRINGS APCH ADVISING THEM OF ACR X'S SPECIFIC POS AND ALT, ROUTING AND THE FACT HE WAS REQUESTING HIGHER ALT BUT THAT I THOUGHT IT UNSAFE TO CLB HIM REFERENCE THE SMA Y WHO WOULD'VE BEEN TALKING TO COLORADO SPRINGS APCH BY THAT TIME. COLORADO SPRINGS APCH FINALLY IDENTED ACR X AND AGREED TO WORK ACR X THROUGH THEIR AIRSPACE.

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.