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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Air carrier flight crew interps ZKC clearance, descending to a previously assigned altitude, conflicting with another aircraft.
| Attributes | |
| ACN | 453613 |
| Time | |
| Date | 199910 |
| Day | Sun |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| State Reference | MO |
| Altitude | msl bound lower : 16000 msl bound upper : 19000 |
| Environment | |
| Flight Conditions | VMC |
| Weather Elements | Turbulence |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zkc.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : enroute altitude change |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : multi engine pilot : atp |
| Experience | flight time last 90 days : 270 flight time total : 14000 flight time type : 8000 |
| ASRS Report | 453613 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : multi engine pilot : commercial |
| Events | |
| Anomaly | altitude deviation : overshoot conflict : airborne less severe non adherence : clearance non adherence : published procedure non adherence : required legal separation |
| Independent Detector | atc equipment other atc equipment : radar other controllera other flight crewa |
| Resolutory Action | controller : issued new clearance controller : issued advisory |
| Consequence | faa : reviewed incident with flight crew faa : investigated |
| Miss Distance | horizontal : 24000 vertical : 700 |
| Supplementary | |
| Problem Areas | ATC Human Performance Flight Crew Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
Flight filed to FL370 on climb out of okc. Advised the rides above FL260 were bumpy over tulsa, so we (aircraft X) leveled at FL250. FL250 was bumpy over tulsa, so on frequency change, we advised ZKC and they offered us FL240. We cruised FL240. Next frequency change, we were given a descent to 16000 ft. I asked if it was our discretion. Center said 'descend to FL230, then descend to 16000 ft.' a few mins later, center said 'descend to FL190 for traffic.' we thought the traffic was between FL190 and FL230, so we expedited our descent to FL200, then slowed to approximately 1000 FPM as to reach 16000 ft on our descent schedule. At FL187, center asked our last assigned altitude. We replied 16000 ft. Center had no reply. On frequency change to stl approach, we asked center if there was a problem back there. Center replied we lost separation, traffic at FL180, 4 mi. Don't worry about it, it's ok. Further follow-up with a phone call finds a possible pilot deviation being checked by the quality assurance people. Further follow-up shows no pilot deviation, improper phraseology. Next time I will ask where the traffic is and/or if we still have a descent to the lower previously assigned altitude.
Original NASA ASRS Text
Title: ACR FLC INTERPS ZKC CLRNC, DSNDING TO A PREVIOUSLY ASSIGNED ALT, CONFLICTING WITH ANOTHER ACFT.
Narrative: FLT FILED TO FL370 ON CLBOUT OF OKC. ADVISED THE RIDES ABOVE FL260 WERE BUMPY OVER TULSA, SO WE (ACFT X) LEVELED AT FL250. FL250 WAS BUMPY OVER TULSA, SO ON FREQ CHANGE, WE ADVISED ZKC AND THEY OFFERED US FL240. WE CRUISED FL240. NEXT FREQ CHANGE, WE WERE GIVEN A DSCNT TO 16000 FT. I ASKED IF IT WAS OUR DISCRETION. CTR SAID 'DSND TO FL230, THEN DSND TO 16000 FT.' A FEW MINS LATER, CTR SAID 'DSND TO FL190 FOR TFC.' WE THOUGHT THE TFC WAS BTWN FL190 AND FL230, SO WE EXPEDITED OUR DSCNT TO FL200, THEN SLOWED TO APPROX 1000 FPM AS TO REACH 16000 FT ON OUR DSCNT SCHEDULE. AT FL187, CTR ASKED OUR LAST ASSIGNED ALT. WE REPLIED 16000 FT. CTR HAD NO REPLY. ON FREQ CHANGE TO STL APCH, WE ASKED CTR IF THERE WAS A PROB BACK THERE. CTR REPLIED WE LOST SEPARATION, TFC AT FL180, 4 MI. DON'T WORRY ABOUT IT, IT'S OK. FURTHER FOLLOW-UP WITH A PHONE CALL FINDS A POSSIBLE PLTDEV BEING CHKED BY THE QUALITY ASSURANCE PEOPLE. FURTHER FOLLOW-UP SHOWS NO PLTDEV, IMPROPER PHRASEOLOGY. NEXT TIME I WILL ASK WHERE THE TFC IS AND/OR IF WE STILL HAVE A DSCNT TO THE LOWER PREVIOUSLY ASSIGNED ALT.
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.