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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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ZLA controller experienced operational error at approximately FL360 when incorrect readback was missed and aircraft descended through occupied altitude.
| Attributes | |
| ACN | 694926 |
| Time | |
| Date | 200604 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : las.airport |
| State Reference | NV |
| Altitude | msl bound lower : 36000 msl bound upper : 37000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : intermediate altitude |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zla.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | A320 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller radar : 6 |
| ASRS Report | 694926 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | atc equipment : conflict alert other controllera |
| Resolutory Action | controller : issued new clearance controller : issued alert |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 29160 vertical : 400 |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
I descended the B737 to FL370. I thought I heard the pilot read back descending to FL370. I observed the B737 go below his assigned altitude of FL370 and turned him 20 degrees left and told him to maintain FL370?
Original NASA ASRS Text
Title: ZLA CTLR EXPERIENCED OPERROR AT APPROX FL360 WHEN INCORRECT READBACK WAS MISSED AND ACFT DSNDED THROUGH OCCUPIED ALT.
Narrative: I DSNDED THE B737 TO FL370. I THOUGHT I HEARD THE PLT READ BACK DSNDING TO FL370. I OBSERVED THE B737 GO BELOW HIS ASSIGNED ALT OF FL370 AND TURNED HIM 20 DEGS L AND TOLD HIM TO MAINTAIN FL370?
Data retrieved from NASA's ASRS site as of January 2009 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.