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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Flight crew descended through assigned FL250 to FL247 before controller alerted crew their assigned altitude was FL250.
| Attributes | |
| ACN | 321250 |
| Time | |
| Date | 199511 |
| Day | Sat |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : dag |
| State Reference | CA |
| Altitude | msl bound lower : 24700 msl bound upper : 25000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla tower : sdf |
| Operator | general aviation : corporate |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 91 |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 100 flight time total : 12500 flight time type : 1200 |
| ASRS Report | 321250 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | altitude deviation : overshoot non adherence : clearance |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance flight crew : returned to intended course or assigned course other |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
The flight was from oxr - las at FL290, the crew was issued several descent clrncs. First to FL260 and then to FL240. Myself and the copilot confirmed FL240 in the altitude select window. At 24700 ft the ATC controller asked us to verify our altitude. The copilot responded with '24700 ft.' the controller responded with a question, 'what was our assigned altitude.' the copilot responded with FL240. The controller said we were assigned FL250. I immediately climbed to FL250. We were advised to call ZLA on the telephone upon reaching our destination. Contributing factors: 1) increased controller workload due to several IFR aircraft and VFR aircraft requesting VFR flight following, 2) faster aircraft (airliner) on similar routing was being vectored underneath our aircraft, 3) due to airspace restrs the controller was under pressure to start our descent, 4) pilot workload increased due to descent phase, change of course, and searching for traffic (our aircraft was being stepped down due to overtaking traffic), and 5) several altitude clrncs issued to several different aircraft within a short time. Quality of human performance: 1) pilots are familiar with route due to numerous flts to same destination (possible complacency), and 2) standard crossing restr (jokur at FL240) not issued (habits).
Original NASA ASRS Text
Title: FLC DSNDED THROUGH ASSIGNED FL250 TO FL247 BEFORE CTLR ALERTED CREW THEIR ASSIGNED ALT WAS FL250.
Narrative: THE FLT WAS FROM OXR - LAS AT FL290, THE CREW WAS ISSUED SEVERAL DSCNT CLRNCS. FIRST TO FL260 AND THEN TO FL240. MYSELF AND THE COPLT CONFIRMED FL240 IN THE ALT SELECT WINDOW. AT 24700 FT THE ATC CTLR ASKED US TO VERIFY OUR ALT. THE COPLT RESPONDED WITH '24700 FT.' THE CTLR RESPONDED WITH A QUESTION, 'WHAT WAS OUR ASSIGNED ALT.' THE COPLT RESPONDED WITH FL240. THE CTLR SAID WE WERE ASSIGNED FL250. I IMMEDIATELY CLBED TO FL250. WE WERE ADVISED TO CALL ZLA ON THE TELEPHONE UPON REACHING OUR DEST. CONTRIBUTING FACTORS: 1) INCREASED CTLR WORKLOAD DUE TO SEVERAL IFR ACFT AND VFR ACFT REQUESTING VFR FLT FOLLOWING, 2) FASTER ACFT (AIRLINER) ON SIMILAR ROUTING WAS BEING VECTORED UNDERNEATH OUR ACFT, 3) DUE TO AIRSPACE RESTRS THE CTLR WAS UNDER PRESSURE TO START OUR DSCNT, 4) PLT WORKLOAD INCREASED DUE TO DSCNT PHASE, CHANGE OF COURSE, AND SEARCHING FOR TFC (OUR ACFT WAS BEING STEPPED DOWN DUE TO OVERTAKING TFC), AND 5) SEVERAL ALT CLRNCS ISSUED TO SEVERAL DIFFERENT ACFT WITHIN A SHORT TIME. QUALITY OF HUMAN PERFORMANCE: 1) PLTS ARE FAMILIAR WITH RTE DUE TO NUMEROUS FLTS TO SAME DEST (POSSIBLE COMPLACENCY), AND 2) STANDARD XING RESTR (JOKUR AT FL240) NOT ISSUED (HABITS).
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.