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ATC failed to issue an amended clearance which resulted in an altitude overshoot. ATC acted fast enough to prevent loss of separation.
| Attributes | |
| ACN | 170834 |
| Time | |
| Date | 199102 |
| Day | Fri |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : cew |
| State Reference | FL |
| Altitude | msl bound lower : 17400 msl bound upper : 18000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zjx |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | cruise other descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 140 flight time total : 10800 flight time type : 130 |
| ASRS Report | 170834 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : overshoot |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | other |
Narrative:
We contacted ZJX on descent to FL240. We were issued clearance to descend to 11000' and given altimeter setting. As we passed through 17400' controller asked us if we were level at FL180. I told him we were descending to 11000' as cleared. By then we were at 17100'. He told us to maintain 17000' and issued an air carrier flight a clearance to stop climb at 16000' and turn 30 degrees. Air carrier replied that he would descend back to 16000' and turn. Then he asked us if we had received our amended clearance to stop descent at FL180. I told him I hadn't heard it. Because I had been on the P/a earlier I asked the first officer if he had acknowledged any clrncs while I was speaking. He said he hadn't. Assumption--probably. The controller did issue a clearance, but it was either blocked or missed during a high workload period. He should have reissued a clearance that wasn't acknowledged.
Original NASA ASRS Text
Title: ATC FAILED TO ISSUE AN AMENDED CLRNC WHICH RESULTED IN AN ALT OVERSHOOT. ATC ACTED FAST ENOUGH TO PREVENT LOSS OF SEPARATION.
Narrative: WE CONTACTED ZJX ON DSNT TO FL240. WE WERE ISSUED CLRNC TO DSND TO 11000' AND GIVEN ALTIMETER SETTING. AS WE PASSED THROUGH 17400' CTLR ASKED US IF WE WERE LEVEL AT FL180. I TOLD HIM WE WERE DSNDING TO 11000' AS CLRED. BY THEN WE WERE AT 17100'. HE TOLD US TO MAINTAIN 17000' AND ISSUED AN ACR FLT A CLRNC TO STOP CLB AT 16000' AND TURN 30 DEGS. ACR REPLIED THAT HE WOULD DSND BACK TO 16000' AND TURN. THEN HE ASKED US IF WE HAD RECEIVED OUR AMENDED CLRNC TO STOP DSNT AT FL180. I TOLD HIM I HADN'T HEARD IT. BECAUSE I HAD BEEN ON THE P/A EARLIER I ASKED THE F/O IF HE HAD ACKNOWLEDGED ANY CLRNCS WHILE I WAS SPEAKING. HE SAID HE HADN'T. ASSUMPTION--PROBABLY. THE CTLR DID ISSUE A CLRNC, BUT IT WAS EITHER BLOCKED OR MISSED DURING A HIGH WORKLOAD PERIOD. HE SHOULD HAVE REISSUED A CLRNC THAT WASN'T ACKNOWLEDGED.
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.