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.