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Flight crew of a B737 could not hold the cruise altitude to which they had reached due to aircraft weight resulting in a slow descent to keep from stalling the aircraft. ATC could not approve their descent due to traffic below causing a potential conflict.
| Attributes | |
| ACN | 426377 |
| Time | |
| Date | 199901 |
| Day | Fri |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : mem |
| State Reference | TN |
| Altitude | msl bound lower : 34400 msl bound upper : 35000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Flight Phase | cruise other descent other |
| Route In Use | enroute airway : zme |
| Flight Plan | IFR |
| Aircraft 2 | |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 240 flight time total : 3900 flight time type : 400 |
| ASRS Report | 426377 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Experience | flight time last 90 days : 210 flight time total : 8000 flight time type : 1600 |
| ASRS Report | 426530 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe |
| Independent Detector | other flight crewa |
| Resolutory Action | none taken : unable |
| Consequence | Other |
| Miss Distance | horizontal : 4000 vertical : 1700 |
| Supplementary | |
| Air Traffic Incident | Pilot Deviation |
Narrative:
To stay clear of WX, climbed to FL350 from FL310 with stall margin of 1.31 G's. Upon reaching FL350, the aircraft was unable to accelerate above .69 mach with maximum continuous power. Within a 30 second period, airspeed dropped from .69 mach to .62 mach. Advised center of need to descend immediately. Instructed by center to maintain altitude due to traffic opposite direction at FL330. Attempted to maintain altitude, but started very slow descent. Had opposite direction traffic on TCASII throughout. Aircraft at FL344 as we passed over FL330 traffic. No TCASII alert ever noticed. Aircraft was IMC at time of incident.
Original NASA ASRS Text
Title: FLC OF A B737 COULD NOT HOLD THE CRUISE ALT TO WHICH THEY HAD REACHED DUE TO ACFT WT RESULTING IN A SLOW DSCNT TO KEEP FROM STALLING THE ACFT. ATC COULD NOT APPROVE THEIR DSCNT DUE TO TFC BELOW CAUSING A POTENTIAL CONFLICT.
Narrative: TO STAY CLR OF WX, CLBED TO FL350 FROM FL310 WITH STALL MARGIN OF 1.31 G'S. UPON REACHING FL350, THE ACFT WAS UNABLE TO ACCELERATE ABOVE .69 MACH WITH MAX CONTINUOUS PWR. WITHIN A 30 SECOND PERIOD, AIRSPD DROPPED FROM .69 MACH TO .62 MACH. ADVISED CTR OF NEED TO DSND IMMEDIATELY. INSTRUCTED BY CTR TO MAINTAIN ALT DUE TO TFC OPPOSITE DIRECTION AT FL330. ATTEMPTED TO MAINTAIN ALT, BUT STARTED VERY SLOW DSCNT. HAD OPPOSITE DIRECTION TFC ON TCASII THROUGHOUT. ACFT AT FL344 AS WE PASSED OVER FL330 TFC. NO TCASII ALERT EVER NOTICED. ACFT WAS IMC AT TIME OF INCIDENT.
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.