Narrative:

I was flying as captain on a flight from roc to atl. We had just reached our cruise altitude of FL350 when center asked us if we could make FL370 for traffic reasons. I knew that we were heavy and at the upper limits of our performance abilities. I, therefore, asked the flight engineer to check the performance charts in order to see if a climb was possible. The specification numbers were as follows: gross weight, 150000 pounds. Zero fuel weight, 127000 pounds. Turbine air temperature, -25. .80 mach chart. Roc temperature 12 degrees C. We should have been able to make FL380. We informed center that we could make FL370 and were given climb instructions. We initiated a climb from FL350 to FL370 at approximately 280 KIAS. As we began our climb the airspeed began to decrease and I had an increasing difficult time maintaining climb performance. Above FL360 the airspeed began to decrease more rapidly, and at FL366 it reached 220 KIAS. I froze the climb and began to feel (along with the first officer) a very light burble sensation on the yoke. We never exceeded a rate of climb above 500 FPM. We informed center that we were no longer able to climb. He asked us if we could give him an additional 300 ft. We could not. We were then given several vectors as was another flight that was also in the area. After a period of time we were allowed to continue our course to atl but were asked to call ZOB after landing. Upon landing, I did call center and spoke to the watch supervisor. He told me that he had to report the traffic conflict and advised that I file a NASA report.

Related reports:

Google
 

Original NASA ASRS Text

Title: B727 UNABLE TO CLB TO CLRED ALT CREATES TFC CONFLICT IN ZOB AIRSPACE.

Narrative: I WAS FLYING AS CAPT ON A FLT FROM ROC TO ATL. WE HAD JUST REACHED OUR CRUISE ALT OF FL350 WHEN CTR ASKED US IF WE COULD MAKE FL370 FOR TFC REASONS. I KNEW THAT WE WERE HVY AND AT THE UPPER LIMITS OF OUR PERFORMANCE ABILITIES. I, THEREFORE, ASKED THE FE TO CHK THE PERFORMANCE CHARTS IN ORDER TO SEE IF A CLB WAS POSSIBLE. THE SPEC NUMBERS WERE AS FOLLOWS: GROSS WT, 150000 LBS. ZERO FUEL WT, 127000 LBS. TURBINE AIR TEMP, -25. .80 MACH CHART. ROC TEMP 12 DEGS C. WE SHOULD HAVE BEEN ABLE TO MAKE FL380. WE INFORMED CTR THAT WE COULD MAKE FL370 AND WERE GIVEN CLB INSTRUCTIONS. WE INITIATED A CLB FROM FL350 TO FL370 AT APPROX 280 KIAS. AS WE BEGAN OUR CLB THE AIRSPD BEGAN TO DECREASE AND I HAD AN INCREASING DIFFICULT TIME MAINTAINING CLB PERFORMANCE. ABOVE FL360 THE AIRSPD BEGAN TO DECREASE MORE RAPIDLY, AND AT FL366 IT REACHED 220 KIAS. I FROZE THE CLB AND BEGAN TO FEEL (ALONG WITH THE FO) A VERY LIGHT BURBLE SENSATION ON THE YOKE. WE NEVER EXCEEDED A RATE OF CLB ABOVE 500 FPM. WE INFORMED CTR THAT WE WERE NO LONGER ABLE TO CLB. HE ASKED US IF WE COULD GIVE HIM AN ADDITIONAL 300 FT. WE COULD NOT. WE WERE THEN GIVEN SEVERAL VECTORS AS WAS ANOTHER FLT THAT WAS ALSO IN THE AREA. AFTER A PERIOD OF TIME WE WERE ALLOWED TO CONTINUE OUR COURSE TO ATL BUT WERE ASKED TO CALL ZOB AFTER LNDG. UPON LNDG, I DID CALL CTR AND SPOKE TO THE WATCH SUPVR. HE TOLD ME THAT HE HAD TO RPT THE TFC CONFLICT AND ADVISED THAT I FILE A NASA RPT.

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.