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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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An A319 crew reports the FMGC transitioned from managed to open descent autonomously and so failed to capture an altitude constraint.
| Attributes | |
| ACN | 663636 |
| Time | |
| Date | 200507 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : las.airport |
| State Reference | NV |
| Altitude | msl single value : 11000 |
| Environment | |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : l30.tracon tower : zzz.tower |
| Operator | common carrier : air carrier |
| Make Model Name | A319 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : intermediate altitude |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| ASRS Report | 663636 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Events | |
| Anomaly | aircraft equipment problem : critical altitude deviation : overshoot non adherence : clearance non adherence : published procedure |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : overrode automation flight crew : returned to assigned altitude |
| Supplementary | |
| Problem Areas | Aircraft Flight Crew Human Performance |
| Primary Problem | Aircraft |
Narrative:
Using managed descent mode cleared to descend via the arrival. Dialed in 8000 ft and we crossed fuzzy at 16000 ft at 250 KTS in managed mode. The next fix was ipumy and the mcdu had the proper altitude for the fix. About 10 mi prior we flew through 11000 ft and the aircraft had switched to open descent without our input. Aircraft was approximately 600 ft low. I recovered to cross ipumy at 11000 ft. The controller did not say anything to us about it.
Original NASA ASRS Text
Title: AN A319 CREW RPTS THE FMGC TRANSITIONED FROM MANAGED TO OPEN DSCNT AUTONOMOUSLY AND SO FAILED TO CAPTURE AN ALT CONSTRAINT.
Narrative: USING MANAGED DSCNT MODE CLRED TO DSND VIA THE ARR. DIALED IN 8000 FT AND WE CROSSED FUZZY AT 16000 FT AT 250 KTS IN MANAGED MODE. THE NEXT FIX WAS IPUMY AND THE MCDU HAD THE PROPER ALT FOR THE FIX. ABOUT 10 MI PRIOR WE FLEW THROUGH 11000 FT AND THE ACFT HAD SWITCHED TO OPEN DSCNT WITHOUT OUR INPUT. ACFT WAS APPROX 600 FT LOW. I RECOVERED TO CROSS IPUMY AT 11000 FT. THE CTLR DID NOT SAY ANYTHING TO US ABOUT IT.
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.