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An air carrier B767 flight crew encounters moderate turbulence during their climb that is strong enough to prevent the aircraft from climbing to their assigned altitude. They were unable to receive clearance to a lower altitude so the captain used emergency authority/authorized to descend.
| Attributes | |
| ACN | 392352 |
| Time | |
| Date | 199801 |
| Day | Fri |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | atc facility : kbv |
| State Reference | FO |
| Altitude | msl bound lower : 29000 msl bound upper : 32000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zny tower : dfw |
| Operator | common carrier : air carrier |
| Make Model Name | Widebody, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | climbout : intermediate altitude descent other other |
| Route In Use | enroute : other oceanic enroute : atlantic |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 392352 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | inflight encounter : weather other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : exited adverse environment flight crew : declared emergency other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Weather |
| Air Traffic Incident | other |
Narrative:
With clearance to climb from a choppy FL290 to FL330 we encountered moderate turbulence passing FL320. The turbulence was so bad that the airspeed flux and loss caused the aircraft to stop climbing and actually start to descend. This with full climb power and an optimum cruising altitude of FL340. I leveled at FL320 to maintain flying speed and ask ny commercial radio to get us permission to descend back to FL290. They said we would have to comply with the FL330 clearance. With turbulence increasing I informed commercial radio and used my emergency authority/authorized to descend back to FL290. I informed commercial radio to ask for any vector or any other lower altitude that would maintain aircraft clearance if needed. ZNY almost immediately came on the HF frequency, via phone patch, with clearance to maintain course and FL290. Turbulence not present at FL290 so flight proceeded from there as normal.
Original NASA ASRS Text
Title: AN ACR B767 FLC ENCOUNTERS MODERATE TURB DURING THEIR CLB THAT IS STRONG ENOUGH TO PREVENT THE ACFT FROM CLBING TO THEIR ASSIGNED ALT. THEY WERE UNABLE TO RECEIVE CLRNC TO A LOWER ALT SO THE CAPT USED EMER AUTH TO DSND.
Narrative: WITH CLRNC TO CLB FROM A CHOPPY FL290 TO FL330 WE ENCOUNTERED MODERATE TURB PASSING FL320. THE TURB WAS SO BAD THAT THE AIRSPD FLUX AND LOSS CAUSED THE ACFT TO STOP CLBING AND ACTUALLY START TO DSND. THIS WITH FULL CLB PWR AND AN OPTIMUM CRUISING ALT OF FL340. I LEVELED AT FL320 TO MAINTAIN FLYING SPD AND ASK NY COMMERCIAL RADIO TO GET US PERMISSION TO DSND BACK TO FL290. THEY SAID WE WOULD HAVE TO COMPLY WITH THE FL330 CLRNC. WITH TURB INCREASING I INFORMED COMMERCIAL RADIO AND USED MY EMER AUTH TO DSND BACK TO FL290. I INFORMED COMMERCIAL RADIO TO ASK FOR ANY VECTOR OR ANY OTHER LOWER ALT THAT WOULD MAINTAIN ACFT CLRNC IF NEEDED. ZNY ALMOST IMMEDIATELY CAME ON THE HF FREQ, VIA PHONE PATCH, WITH CLRNC TO MAINTAIN COURSE AND FL290. TURB NOT PRESENT AT FL290 SO FLT PROCEEDED FROM THERE AS NORMAL.
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.