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Air carrier-large transport descended into conflict with another air carrier-large transport resulting in less than standard separation.
| Attributes | |
| ACN | 81813 |
| Time | |
| Date | 198802 |
| Day | Thu |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : den |
| State Reference | CO |
| Altitude | msl bound lower : 10000 msl bound upper : 10400 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdv tracon : den tracon : bwi |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | descent other |
| Route In Use | arrival star : star |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : flight engineer pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 17000 flight time type : 750 |
| ASRS Report | 81813 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 90 flight time total : 10000 flight time type : 500 |
| ASRS Report | 81807 |
| Events | |
| Anomaly | altitude deviation : overshoot conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | other controllera other flight crewa |
| Resolutory Action | controller : issued new clearance none taken : insufficient time |
| Consequence | Other |
| Miss Distance | horizontal : 12000 vertical : 400 |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Den center issued us a descent clearance from 35000' to 17000' to cross keane at 17000' and 250 KTS. Prior to reaching 17000' we were reclred to 10000' and delete 250 speed restriction. Prior to 10000' we went over to approach control. We were ATP approximately 12000' on ssw vectors for runway 26 den when I spotted large transport Y slightly below on an easterly heading. I felt the vector and apparent lack of vertical sep was closer than I would have liked, but since it was clear and I had the traffic I made no issue of it with the controller. When we were approximately 10200' we were issued a clearance to 11000'. I commented to the controller, 'a little late, isn't it?' he responded that 11000' was the altitude to which we were cleared. If it was it is strange that I read back the clearance 10000', the other 2 crewmembers understood 10000' and that was the altitude set in the altitude alert.
Original NASA ASRS Text
Title: ACR-LGT DESCENDED INTO CONFLICT WITH ANOTHER ACR-LGT RESULTING IN LESS THAN STANDARD SEPARATION.
Narrative: DEN CENTER ISSUED US A DSCNT CLRNC FROM 35000' TO 17000' TO CROSS KEANE AT 17000' AND 250 KTS. PRIOR TO REACHING 17000' WE WERE RECLRED TO 10000' AND DELETE 250 SPD RESTRICTION. PRIOR TO 10000' WE WENT OVER TO APCH CTL. WE WERE ATP APPROX 12000' ON SSW VECTORS FOR RWY 26 DEN WHEN I SPOTTED LGT Y SLIGHTLY BELOW ON AN EASTERLY HDG. I FELT THE VECTOR AND APPARENT LACK OF VERT SEP WAS CLOSER THAN I WOULD HAVE LIKED, BUT SINCE IT WAS CLR AND I HAD THE TFC I MADE NO ISSUE OF IT WITH THE CTLR. WHEN WE WERE APPROX 10200' WE WERE ISSUED A CLRNC TO 11000'. I COMMENTED TO THE CTLR, 'A LITTLE LATE, ISN'T IT?' HE RESPONDED THAT 11000' WAS THE ALT TO WHICH WE WERE CLRED. IF IT WAS IT IS STRANGE THAT I READ BACK THE CLRNC 10000', THE OTHER 2 CREWMEMBERS UNDERSTOOD 10000' AND THAT WAS THE ALT SET IN THE ALT ALERT.
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.