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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Operational error occurred when trainee controller descended an air carrier B737 to FL310 vice FL330 with unknown traffic at FL310. Instructor controller attempted to reverse the descent but separation was lost. B737 flight crew reported seeing an aircraft (white DOT) on the TCASII, no TA or RA received.
| Attributes | |
| ACN | 365911 |
| Time | |
| Date | 199704 |
| Day | Sat |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : sfk |
| State Reference | PA |
| Altitude | msl bound lower : 31000 msl bound upper : 33000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob |
| Operator | common carrier : air carrier |
| Make Model Name | B737-500 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | climbout : intermediate altitude descent other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | general aviation : corporate |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | instruction : instructor |
| Qualification | controller : radar pilot : private |
| Experience | controller military : 5 controller radar : 17 controller supervisory : 2 flight time total : 110 |
| ASRS Report | 365911 |
| Person 2 | |
| Affiliation | government : faa |
| Function | instruction : trainee |
| Qualification | controller : non radar |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation |
| Independent Detector | other other : unspecified other other : unspecified atc |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Miss Distance | horizontal : 18000 vertical : 1000 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
I was instructing trainee at a high altitude sector. She made several bad decisions, and I tried to offer advice on how to fix the problems. The last mistake was hers. Both I and the D side controller told her to descend air carrier X to FL330. For some reason, she issued FL310, same altitude as the traffic. We tried to stop the descent at FL330, no luck. Supplemental information from acn 365919: we were descending through about FL323 when controller issued a clearance to level at FL330. We informed controller we were through FL330 and we would stop descent and climb back to FL330. It took approximately 400 ft for us to change descent into a climb. As we rounded out at FL319 we saw an aircraft (white DOT, no RA or no TA) appear on TCASII directly below at FL310. Simultaneously, a new, different voice came over the radio telling us he needs us at FL330 right away. We acknowledged and we climbed back to FL330 as he spoke. The earlier clrncs (first voice -- female) had no sense or urgency or doubt as to timbre or pattern. The second voice (male) was firm, but not panicky or excited. It was probably that of a more experienced controller or supervisor.
Original NASA ASRS Text
Title: OPERROR OCCURRED WHEN TRAINEE CTLR DSNDED AN ACR B737 TO FL310 VICE FL330 WITH UNKNOWN TFC AT FL310. INSTRUCTOR CTLR ATTEMPTED TO REVERSE THE DSCNT BUT SEPARATION WAS LOST. B737 FLC RPTED SEEING AN ACFT (WHITE DOT) ON THE TCASII, NO TA OR RA RECEIVED.
Narrative: I WAS INSTRUCTING TRAINEE AT A HIGH ALT SECTOR. SHE MADE SEVERAL BAD DECISIONS, AND I TRIED TO OFFER ADVICE ON HOW TO FIX THE PROBS. THE LAST MISTAKE WAS HERS. BOTH I AND THE D SIDE CTLR TOLD HER TO DSND ACR X TO FL330. FOR SOME REASON, SHE ISSUED FL310, SAME ALT AS THE TFC. WE TRIED TO STOP THE DSCNT AT FL330, NO LUCK. SUPPLEMENTAL INFO FROM ACN 365919: WE WERE DSNDING THROUGH ABOUT FL323 WHEN CTLR ISSUED A CLRNC TO LEVEL AT FL330. WE INFORMED CTLR WE WERE THROUGH FL330 AND WE WOULD STOP DSCNT AND CLB BACK TO FL330. IT TOOK APPROX 400 FT FOR US TO CHANGE DSCNT INTO A CLB. AS WE ROUNDED OUT AT FL319 WE SAW AN ACFT (WHITE DOT, NO RA OR NO TA) APPEAR ON TCASII DIRECTLY BELOW AT FL310. SIMULTANEOUSLY, A NEW, DIFFERENT VOICE CAME OVER THE RADIO TELLING US HE NEEDS US AT FL330 RIGHT AWAY. WE ACKNOWLEDGED AND WE CLBED BACK TO FL330 AS HE SPOKE. THE EARLIER CLRNCS (FIRST VOICE -- FEMALE) HAD NO SENSE OR URGENCY OR DOUBT AS TO TIMBRE OR PATTERN. THE SECOND VOICE (MALE) WAS FIRM, BUT NOT PANICKY OR EXCITED. IT WAS PROBABLY THAT OF A MORE EXPERIENCED CTLR OR SUPVR.
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.