Narrative:

I was crewing flight from fll as first officer. I was flying the aircraft. We were initially told to cross over lal at FL350, but then the controller asked us to increase our rate of climb to accommodate traffic in the area. We weighted about 106000# and were climbing at .74 at the time, so I increased the rate of climb until the mach settled at .70. Out of FL335 the mach had increased to .74 and we were climbing at 1500 FPM, so I further increased the rate to 2000 FPM on the trim wheel. Out of FL342 the airspeed indicated 250 and was slowly decreasing, so I reduced the rate of climb to 500 FPM on the trim wheel to accelerate into FL350. At this point the aircraft began a slight dutch roll (which it had been doing off and on all day since the aircraft's yaw damper was inoperative). Airspeed was not responding well to maximum power and was in fact decreasing slowly. I leveled the aircraft at FL349 and mentioned my concern to captain. We noted that the RAT was at -28 degrees C and that maximum power was set. The dutch roll continued to occur as the airspeed decreased even further to 215. The aircraft buffeted slightly as captain requested lower, only to be told that we would have to wait until FL330 traffic at 12 O'clock cleared. I expressed concern to the captain and suggested a turn to facilitate a descent as soon as possible. The dutch roll became worse and the buffeting more frequent with the airspeed hovering around FL210. We felt that this wasn't going to hold much longer so I disengaged the autoplt and began a very shallow descent. The captain was trying to get through to center to relate our situation only to get blocked by other aircraft. I transferred control of the aircraft to captain and relayed to center that we were unable FL350 and were in fact coming out of the altitude at that time. Center turned our traffic (air carrier Y medium large transport) 90 degrees left and then issued us a left turn to 270 degrees. The airspeed slowly returned to normal, but the dutch roll continue at a decreasing rate. ZJX asked us to contact FAA quality assurance in mia, stating that the reason was due to an altitude conflict over lal VOR. I believe there are several things which could have contributed to the situation: yaw damper being inoperative and possible further autoplt problem; my relative inexperience in the situation (i.e., relatively heavy airplane, high altitude with yaw damper inoperative); desire to help center out by trying to get to altitude a little too soon; and possible weight tab error at departure station (aircraft was good for that altitude by a little over 4000# and performed more like it was 4000# overweight). There is no altitude limitation for an inoperative yaw damper in our book for the medium large transport. Maybe there should be.

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Original NASA ASRS Text

Title: ACR MLG APCHED A LOW SPEED STALL WHILE CLIMBING TO CRUISE ALT.

Narrative: I WAS CREWING FLT FROM FLL AS F/O. I WAS FLYING THE ACFT. WE WERE INITIALLY TOLD TO CROSS OVER LAL AT FL350, BUT THEN THE CTLR ASKED US TO INCREASE OUR RATE OF CLB TO ACCOMMODATE TFC IN THE AREA. WE WEIGHTED ABOUT 106000# AND WERE CLBING AT .74 AT THE TIME, SO I INCREASED THE RATE OF CLB UNTIL THE MACH SETTLED AT .70. OUT OF FL335 THE MACH HAD INCREASED TO .74 AND WE WERE CLBING AT 1500 FPM, SO I FURTHER INCREASED THE RATE TO 2000 FPM ON THE TRIM WHEEL. OUT OF FL342 THE AIRSPD INDICATED 250 AND WAS SLOWLY DECREASING, SO I REDUCED THE RATE OF CLB TO 500 FPM ON THE TRIM WHEEL TO ACCELERATE INTO FL350. AT THIS POINT THE ACFT BEGAN A SLIGHT DUTCH ROLL (WHICH IT HAD BEEN DOING OFF AND ON ALL DAY SINCE THE ACFT'S YAW DAMPER WAS INOP). AIRSPD WAS NOT RESPONDING WELL TO MAX PWR AND WAS IN FACT DECREASING SLOWLY. I LEVELED THE ACFT AT FL349 AND MENTIONED MY CONCERN TO CAPT. WE NOTED THAT THE RAT WAS AT -28 DEGS C AND THAT MAX PWR WAS SET. THE DUTCH ROLL CONTINUED TO OCCUR AS THE AIRSPD DECREASED EVEN FURTHER TO 215. THE ACFT BUFFETED SLIGHTLY AS CAPT REQUESTED LOWER, ONLY TO BE TOLD THAT WE WOULD HAVE TO WAIT UNTIL FL330 TFC AT 12 O'CLOCK CLRED. I EXPRESSED CONCERN TO THE CAPT AND SUGGESTED A TURN TO FACILITATE A DSCNT ASAP. THE DUTCH ROLL BECAME WORSE AND THE BUFFETING MORE FREQUENT WITH THE AIRSPD HOVERING AROUND FL210. WE FELT THAT THIS WASN'T GOING TO HOLD MUCH LONGER SO I DISENGAGED THE AUTOPLT AND BEGAN A VERY SHALLOW DSCNT. THE CAPT WAS TRYING TO GET THROUGH TO CENTER TO RELATE OUR SITUATION ONLY TO GET BLOCKED BY OTHER ACFT. I TRANSFERRED CONTROL OF THE ACFT TO CAPT AND RELAYED TO CENTER THAT WE WERE UNABLE FL350 AND WERE IN FACT COMING OUT OF THE ALT AT THAT TIME. CENTER TURNED OUR TFC (ACR Y MLG) 90 DEGS LEFT AND THEN ISSUED US A LEFT TURN TO 270 DEGS. THE AIRSPD SLOWLY RETURNED TO NORMAL, BUT THE DUTCH ROLL CONTINUE AT A DECREASING RATE. ZJX ASKED US TO CONTACT FAA QUALITY ASSURANCE IN MIA, STATING THAT THE REASON WAS DUE TO AN ALT CONFLICT OVER LAL VOR. I BELIEVE THERE ARE SEVERAL THINGS WHICH COULD HAVE CONTRIBUTED TO THE SITUATION: YAW DAMPER BEING INOP AND POSSIBLE FURTHER AUTOPLT PROB; MY RELATIVE INEXPERIENCE IN THE SITUATION (I.E., RELATIVELY HVY AIRPLANE, HIGH ALT WITH YAW DAMPER INOP); DESIRE TO HELP CENTER OUT BY TRYING TO GET TO ALT A LITTLE TOO SOON; AND POSSIBLE WT TAB ERROR AT DEP STATION (ACFT WAS GOOD FOR THAT ALT BY A LITTLE OVER 4000# AND PERFORMED MORE LIKE IT WAS 4000# OVERWEIGHT). THERE IS NO ALT LIMITATION FOR AN INOP YAW DAMPER IN OUR BOOK FOR THE MLG. MAYBE THERE SHOULD BE.

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.