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An A300 cargo flight misses their altitude crossing restr by 500 ft because of an FMC leveloff response to an overspd condition 15 mi north of gilmore, tn.
| Attributes | |
| ACN | 536359 |
| Time | |
| Date | 200201 |
| Day | Thu |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : gqe.vor |
| State Reference | AR |
| Altitude | msl bound lower : 12000 msl bound upper : 12500 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tower : zzz.tower |
| Operator | common carrier : air carrier |
| Make Model Name | A300 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other other vortac |
| Flight Phase | descent : approach |
| Route In Use | arrival star : gilmore |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 152 flight time total : 8429 flight time type : 270 |
| ASRS Report | 536359 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 10000 flight time type : 1000 |
| ASRS Report | 535286 |
| Events | |
| Anomaly | altitude deviation : crossing restriction not met altitude deviation : undershoot non adherence : clearance other anomaly |
| Independent Detector | aircraft equipment other aircraft equipment : overspeed ctl other controllera other flight crewa other flight crewb |
| Resolutory Action | aircraft : automation overrode flight crew controller : issued advisory none taken : unable other |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Aircraft |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Inbound to mem on the gilmore arrival. First descent clearance was to FL240, maximum forward speed. Subsequent clearance was to cross 15 NM north of gilmore at 12000 ft, expect direct gilmore. The captain entered the constraint into the FMS while still proceeding on the farmington transition at maximum forward speed. Aircraft autoflt system was engaged in the profile mode and indicated that we would make the crossing restr. Several mi later we were cleared direct gilmore with same crossing restr. After entering the 'direct to' in the FMS and completing calculations, the autoflt system then nosed the aircraft over to make the restr. While going through approximately 16000 ft, aircraft airspeed rapidly went into redline triggering the overspd warning and the autoflt system to level off the aircraft to regain airspeed control. The captain selected a lower level of automation and continued the descent. The leveloff caused us to miss the crossing restr by 500 ft. Just as we realized the inability to make the restr, ATC asked if we were going to make it and I responded that we were not. With no further comment, the controller handed over to memphis approach control. Fully automated flight sequences are sometimes not able to handle quick changes and profiles other than 'standard.' maximum forward speed and the direct clearance caused the aircraft to descend at a faster rate causing the overspd. Full automation is not programmed to handle 'expect' clrncs. Perhaps going to a lower level of automation earlier would have prevented the overspd and subsequent leveloff.
Original NASA ASRS Text
Title: AN A300 CARGO FLT MISSES THEIR ALT XING RESTR BY 500 FT BECAUSE OF AN FMC LEVELOFF RESPONSE TO AN OVERSPD CONDITION 15 MI N OF GILMORE, TN.
Narrative: INBOUND TO MEM ON THE GILMORE ARR. FIRST DSCNT CLRNC WAS TO FL240, MAX FORWARD SPD. SUBSEQUENT CLRNC WAS TO CROSS 15 NM N OF GILMORE AT 12000 FT, EXPECT DIRECT GILMORE. THE CAPT ENTERED THE CONSTRAINT INTO THE FMS WHILE STILL PROCEEDING ON THE FARMINGTON TRANSITION AT MAX FORWARD SPD. ACFT AUTOFLT SYS WAS ENGAGED IN THE PROFILE MODE AND INDICATED THAT WE WOULD MAKE THE XING RESTR. SEVERAL MI LATER WE WERE CLRED DIRECT GILMORE WITH SAME XING RESTR. AFTER ENTERING THE 'DIRECT TO' IN THE FMS AND COMPLETING CALCULATIONS, THE AUTOFLT SYS THEN NOSED THE ACFT OVER TO MAKE THE RESTR. WHILE GOING THROUGH APPROX 16000 FT, ACFT AIRSPD RAPIDLY WENT INTO REDLINE TRIGGERING THE OVERSPD WARNING AND THE AUTOFLT SYS TO LEVEL OFF THE ACFT TO REGAIN AIRSPD CTL. THE CAPT SELECTED A LOWER LEVEL OF AUTOMATION AND CONTINUED THE DSCNT. THE LEVELOFF CAUSED US TO MISS THE XING RESTR BY 500 FT. JUST AS WE REALIZED THE INABILITY TO MAKE THE RESTR, ATC ASKED IF WE WERE GOING TO MAKE IT AND I RESPONDED THAT WE WERE NOT. WITH NO FURTHER COMMENT, THE CTLR HANDED OVER TO MEMPHIS APCH CTL. FULLY AUTOMATED FLT SEQUENCES ARE SOMETIMES NOT ABLE TO HANDLE QUICK CHANGES AND PROFILES OTHER THAN 'STANDARD.' MAX FORWARD SPD AND THE DIRECT CLRNC CAUSED THE ACFT TO DSND AT A FASTER RATE CAUSING THE OVERSPD. FULL AUTOMATION IS NOT PROGRAMMED TO HANDLE 'EXPECT' CLRNCS. PERHAPS GOING TO A LOWER LEVEL OF AUTOMATION EARLIER WOULD HAVE PREVENTED THE OVERSPD AND SUBSEQUENT LEVELOFF.
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.