Narrative:

We were cleared to climb to FL350, which was the highest the airplane could cruise at our gross weight. As we reached FL347, the aircraft climb rate reduced momentarily, perhaps due to the atmospheric conditions (temperature), and was starting to slowly climb up to FL350. At that time, the controller told us that our transponder showed us 300 ft below FL350, and urgently ordered us to turn 60 degrees left of course. He then told another flight to turn 40 des left of their course. Shortly thereafter, we were cleared direct to csn, and we had attained FL350 in that short time. The controller admonished us to report any leveloff in the future. We did not answer that admonishment, but another pilot on the frequency responded with a sarcastic 'OOOH!,' which probably incensed the controller. Although our aircraft was struggling to reach FL350, we never actually leveled off at FL347, as we continued a gradual climb up to FL350. The 60 degree left turn did inhibit our climb capability during the turn. This entire event surprised me, as aircraft do sometimes have lower vertical climb rates at higher gross weights, but we never leveled off and it was not us that responded sarcastically to the controller. Supplemental information from acn 599004: MD88's operated near their maximum performance ceiling frequently experience rapid climb rates and then reduced climb rates which dip under 500 FPM for many seconds before recovering. Use of vertical speed can help to maintain a 500 FPM climb rate, but eliminates stall protection found in VNAV mode. Thus, use of vertical speed requires vigilance on the part of crew members who use this technique operating near aircraft performance envelopes. Advising ATC that the climb rate may alternatively fall below 500 FPM for a short period before climb rate recovery, might help as an alternative. Without TCASII display of the other aircraft and with no traffic advisory from atl we had no idea of any potential conflict and flowed with the idiosyncratic MD88 VNAV. As PNF working communications with ATC I should perhaps be more specific about what the airplane is doing and see how I can help ATC. ATC asked what our altitude was for a reason and perhaps I appeared somewhat glib when queried about altitude.

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Original NASA ASRS Text

Title: MD80 ON CLBOUT EXPERIENCED ATC TURN TO AVOID OTHER ACFT BECAUSE OF SLOW CLB IN ZDC AIRSPACE.

Narrative: WE WERE CLRED TO CLB TO FL350, WHICH WAS THE HIGHEST THE AIRPLANE COULD CRUISE AT OUR GROSS WT. AS WE REACHED FL347, THE ACFT CLB RATE REDUCED MOMENTARILY, PERHAPS DUE TO THE ATMOSPHERIC CONDITIONS (TEMP), AND WAS STARTING TO SLOWLY CLB UP TO FL350. AT THAT TIME, THE CTLR TOLD US THAT OUR XPONDER SHOWED US 300 FT BELOW FL350, AND URGENTLY ORDERED US TO TURN 60 DEGS L OF COURSE. HE THEN TOLD ANOTHER FLT TO TURN 40 DES L OF THEIR COURSE. SHORTLY THEREAFTER, WE WERE CLRED DIRECT TO CSN, AND WE HAD ATTAINED FL350 IN THAT SHORT TIME. THE CTLR ADMONISHED US TO RPT ANY LEVELOFF IN THE FUTURE. WE DID NOT ANSWER THAT ADMONISHMENT, BUT ANOTHER PLT ON THE FREQ RESPONDED WITH A SARCASTIC 'OOOH!,' WHICH PROBABLY INCENSED THE CTLR. ALTHOUGH OUR ACFT WAS STRUGGLING TO REACH FL350, WE NEVER ACTUALLY LEVELED OFF AT FL347, AS WE CONTINUED A GRADUAL CLB UP TO FL350. THE 60 DEG L TURN DID INHIBIT OUR CLB CAPABILITY DURING THE TURN. THIS ENTIRE EVENT SURPRISED ME, AS ACFT DO SOMETIMES HAVE LOWER VERT CLB RATES AT HIGHER GROSS WTS, BUT WE NEVER LEVELED OFF AND IT WAS NOT US THAT RESPONDED SARCASTICALLY TO THE CTLR. SUPPLEMENTAL INFO FROM ACN 599004: MD88'S OPERATED NEAR THEIR MAX PERFORMANCE CEILING FREQUENTLY EXPERIENCE RAPID CLB RATES AND THEN REDUCED CLB RATES WHICH DIP UNDER 500 FPM FOR MANY SECONDS BEFORE RECOVERING. USE OF VERT SPD CAN HELP TO MAINTAIN A 500 FPM CLB RATE, BUT ELIMINATES STALL PROTECTION FOUND IN VNAV MODE. THUS, USE OF VERT SPD REQUIRES VIGILANCE ON THE PART OF CREW MEMBERS WHO USE THIS TECHNIQUE OPERATING NEAR ACFT PERFORMANCE ENVELOPES. ADVISING ATC THAT THE CLB RATE MAY ALTERNATIVELY FALL BELOW 500 FPM FOR A SHORT PERIOD BEFORE CLB RATE RECOVERY, MIGHT HELP AS AN ALTERNATIVE. WITHOUT TCASII DISPLAY OF THE OTHER ACFT AND WITH NO TFC ADVISORY FROM ATL WE HAD NO IDEA OF ANY POTENTIAL CONFLICT AND FLOWED WITH THE IDIOSYNCRATIC MD88 VNAV. AS PNF WORKING COMS WITH ATC I SHOULD PERHAPS BE MORE SPECIFIC ABOUT WHAT THE AIRPLANE IS DOING AND SEE HOW I CAN HELP ATC. ATC ASKED WHAT OUR ALT WAS FOR A REASON AND PERHAPS I APPEARED SOMEWHAT GLIB WHEN QUERIED ABOUT ALT.

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.