 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Altitude deviation. Altitude undershot on descent. Altitude crossing restriction not met. Unable callback strip returned.
| Attributes | |
| ACN | 147141 |
| Time | |
| Date | 199006 |
| Day | Sun |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : pmd |
| State Reference | CA |
| Altitude | msl bound lower : 24000 msl bound upper : 25000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| 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 : 200 flight time total : 15000 flight time type : 400 |
| ASRS Report | 147141 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : crossing restriction not met altitude deviation : undershoot non adherence : clearance |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance none taken : unable |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
My flight was cleared to cross 10 west of palmdale at FL240. The FMC was set with that restriction. This setting was sumped from vertical navigation when the altitude warning was reset to FL240 from FL330. When this happens on the medium large transport, there is no warning or message displayed. As a result, we as well as the controller realized too late that the aircraft was not going to make the restriction. (Progress??) we advised ATC that we were unable to comply and they advised us to continue as there was no conflict. I called the supervisor after landing to explain what had happened. Automated flight holds many traps for us, most of which are altitude related. We must be even more vigilant than we were before.
Original NASA ASRS Text
Title: ALT DEVIATION. ALT UNDERSHOT ON DESCENT. ALT CROSSING RESTRICTION NOT MET. UNABLE CALLBACK STRIP RETURNED.
Narrative: MY FLT WAS CLRED TO CROSS 10 W OF PALMDALE AT FL240. THE FMC WAS SET WITH THAT RESTRICTION. THIS SETTING WAS SUMPED FROM VERT NAV WHEN THE ALT WARNING WAS RESET TO FL240 FROM FL330. WHEN THIS HAPPENS ON THE MLG, THERE IS NO WARNING OR MESSAGE DISPLAYED. AS A RESULT, WE AS WELL AS THE CTLR REALIZED TOO LATE THAT THE ACFT WAS NOT GOING TO MAKE THE RESTRICTION. (PROGRESS??) WE ADVISED ATC THAT WE WERE UNABLE TO COMPLY AND THEY ADVISED US TO CONTINUE AS THERE WAS NO CONFLICT. I CALLED THE SUPVR AFTER LNDG TO EXPLAIN WHAT HAD HAPPENED. AUTOMATED FLT HOLDS MANY TRAPS FOR US, MOST OF WHICH ARE ALT RELATED. WE MUST BE EVEN MORE VIGILANT THAN WE WERE BEFORE.
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.