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Medium large transport climb to occupied altitude had less than standard separation from light transport. System error.
| Attributes | |
| ACN | 214496 |
| Time | |
| Date | 199207 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : den |
| State Reference | CO |
| Altitude | msl bound lower : 24800 msl bound upper : 25000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdv |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | general aviation : corporate |
| Make Model Name | Light Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other |
| Route In Use | enroute : direct |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 2 |
| ASRS Report | 214496 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 7500 flight time type : 1200 |
| ASRS Report | 214497 |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 25800 vertical : 0 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
I was working the radar position on sector 5. The traffic complexity at the time was 4 out of 5 aircraft were deviating because of WX and there were reports of moderate turbulence below FL260. The sector to the south of sector 5 had holding aircraft deviating into sector 5. I had an small transport wbound at FL260. The small transport needed to deviate for WX and would not deviation north. I approved a south deviation for the small transport. I also had a jet arriving at aspen from the east that I was trying to descend. 3 denver departures climbed out wbound. I cleared the first 2 to FL250 because of the small transport. The third departure was an medium large transport behind an light transport. I cleared the medium large transport to FL250 and turned 20 degrees right for climb. The medium large transport had too much overtake on the light transport. I recognized the overtake but the medium large transport was already above FL240 when I amended his altitude to FL240. Supplemental information from acn 214497. Medium large transport level at 230; cleared to 250 by ATC. Climb was rapid due to desire to top build-up in area. As medium large transport neared level-off at 250 (out of 24800), controller reclred flight to 240, with 'expedite.' medium large transport returned to 240 without incident. Both captain and first officer responded aloud to clearance from 230 to 250. First officer readback '250' to ATC.
Original NASA ASRS Text
Title: MLG CLB TO OCCUPIED ALT HAD LTSS FROM LTT. SYS ERROR.
Narrative: I WAS WORKING THE RADAR POS ON SECTOR 5. THE TFC COMPLEXITY AT THE TIME WAS 4 OUT OF 5 ACFT WERE DEVIATING BECAUSE OF WX AND THERE WERE RPTS OF MODERATE TURB BELOW FL260. THE SECTOR TO THE S OF SECTOR 5 HAD HOLDING ACFT DEVIATING INTO SECTOR 5. I HAD AN SMT WBOUND AT FL260. THE SMT NEEDED TO DEVIATE FOR WX AND WOULD NOT DEV N. I APPROVED A S DEV FOR THE SMT. I ALSO HAD A JET ARRIVING AT ASPEN FROM THE E THAT I WAS TRYING TO DSND. 3 DENVER DEPS CLBED OUT WBOUND. I CLRED THE FIRST 2 TO FL250 BECAUSE OF THE SMT. THE THIRD DEP WAS AN MLG BEHIND AN LTT. I CLRED THE MLG TO FL250 AND TURNED 20 DEGS R FOR CLB. THE MLG HAD TOO MUCH OVERTAKE ON THE LTT. I RECOGNIZED THE OVERTAKE BUT THE MLG WAS ALREADY ABOVE FL240 WHEN I AMENDED HIS ALT TO FL240. SUPPLEMENTAL INFO FROM ACN 214497. MLG LEVEL AT 230; CLRED TO 250 BY ATC. CLB WAS RAPID DUE TO DESIRE TO TOP BUILD-UP IN AREA. AS MLG NEARED LEVEL-OFF AT 250 (OUT OF 24800), CTLR RECLRED FLT TO 240, WITH 'EXPEDITE.' MLG RETURNED TO 240 WITHOUT INCIDENT. BOTH CAPT AND FO RESPONDED ALOUD TO CLRNC FROM 230 TO 250. FO READBACK '250' TO ATC.
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.