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B777 aircraft on STAR with multiple clrncs was cleared to 11000 ft and flight crew heard it as 7000 ft. Descent was started until controller intervened and verified the altitude clearance of 11000 ft.
| Attributes | |
| ACN | 392472 |
| Time | |
| Date | 199801 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : oak airport : sfo |
| State Reference | CA |
| Altitude | msl bound lower : 10600 msl bound upper : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B777-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | cruise other descent other |
| Route In Use | arrival other arrival star : star enroute airway : oak |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 35 flight time total : 10900 flight time type : 35 |
| ASRS Report | 392472 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 240 flight time total : 7500 flight time type : 400 |
| ASRS Report | 392470 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | flight crew : returned to intended course or assigned course other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
We were a B777 en route ord to sfo. The first officer was flying. In our descent to sfo, ZOA gave us holding at cedes intersection at 11000 ft expect further clearance at XX50Z. Clearance received at XX35Z. Entered holding at XX40Z. On the second turn in holding ZOA cleared us direct to cedes and changed to bay approach control. We changed and requested the 'FMS bridge visual approach.' we were cleared direct archi, maintain 11000 ft, expect the FMS bridge visual. We interpreted the 11000 ft to be 7000 ft and commenced a descent. The controller called to remind us to maintain 11000 ft at approximately 10600 ft and the aircraft was returned to 11000 ft. The remainder of the flight was routine. This event would appear to be a crew coordination short-coming. With clrncs, holding, frequency changes and aircraft descent happening within a matter of seconds, the event controled us rather than the other way around.
Original NASA ASRS Text
Title: B777 ACFT ON STAR WITH MULTIPLE CLRNCS WAS CLRED TO 11000 FT AND FLC HEARD IT AS 7000 FT. DSCNT WAS STARTED UNTIL CTLR INTERVENED AND VERIFIED THE ALT CLRNC OF 11000 FT.
Narrative: WE WERE A B777 ENRTE ORD TO SFO. THE FO WAS FLYING. IN OUR DSCNT TO SFO, ZOA GAVE US HOLDING AT CEDES INTXN AT 11000 FT EXPECT FURTHER CLRNC AT XX50Z. CLRNC RECEIVED AT XX35Z. ENTERED HOLDING AT XX40Z. ON THE SECOND TURN IN HOLDING ZOA CLRED US DIRECT TO CEDES AND CHANGED TO BAY APCH CTL. WE CHANGED AND REQUESTED THE 'FMS BRIDGE VISUAL APCH.' WE WERE CLRED DIRECT ARCHI, MAINTAIN 11000 FT, EXPECT THE FMS BRIDGE VISUAL. WE INTERPRETED THE 11000 FT TO BE 7000 FT AND COMMENCED A DSCNT. THE CTLR CALLED TO REMIND US TO MAINTAIN 11000 FT AT APPROX 10600 FT AND THE ACFT WAS RETURNED TO 11000 FT. THE REMAINDER OF THE FLT WAS ROUTINE. THIS EVENT WOULD APPEAR TO BE A CREW COORD SHORT-COMING. WITH CLRNCS, HOLDING, FREQ CHANGES AND ACFT DSCNT HAPPENING WITHIN A MATTER OF SECONDS, THE EVENT CTLED US RATHER THAN THE OTHER WAY AROUND.
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.