Narrative:

Prior to departure a baggage cart hit the right wing. No real visible damage was noticed. Maintenance inspected and signed the book off. The flight plan had us going to FL330. While at FL330, about 1 hour into the flight, just past bce, we were deviating around some large cells. Occasional light chop. Seatbelt sign on. Aircraft engine and wing anti-ice on as we had just come through a cloud layer. Aircraft weight 129000 pounds. The deviations and convective activity did not seem to be anything unusual. We started to feel a buffet and rumble. Having not felt that before, and not being close to our maximum weight for the altitude, the first officer and I thought it was a structural problem, maybe a problem with the right wing. As the buffeting the rumble got worse the aircraft was having a hard time maintaining altitude and wings level. The first officer kicked off the autoplt and autothrottles. I told her to 'let the plane come down.' she lowered the nose and I called ATC to declare an emergency and ask about a suitable place to land. As the plane was coming through about FL330 I took the plane from the first officer. I added some more power, retrimmed the aircraft, and leveled at FL290. I was still hand-flying the plane and it was flying fine. I then thought the problem was not structural and that we had approached a stall. I gave the plane back to the first officer, made a PA, and called dispatch. At no time were the engines close to being over-boosted. We found out later that there was mountain wave activity in the area. I think a combination of mountain wave, lack of power from aircraft engine and wing anti-ice, and possible slow or no response from the autothrottles, contributed to this event.

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Original NASA ASRS Text

Title: AN MD80 CAPT RPTED THAT HE AND HIS FO DID NOT RECOGNIZE THE ACFT'S STALLED ATTITUDE.

Narrative: PRIOR TO DEP A BAGGAGE CART HIT THE R WING. NO REAL VISIBLE DAMAGE WAS NOTICED. MAINT INSPECTED AND SIGNED THE BOOK OFF. THE FLT PLAN HAD US GOING TO FL330. WHILE AT FL330, ABOUT 1 HR INTO THE FLT, JUST PAST BCE, WE WERE DEVIATING AROUND SOME LARGE CELLS. OCCASIONAL LIGHT CHOP. SEATBELT SIGN ON. ACFT ENG AND WING ANTI-ICE ON AS WE HAD JUST COME THROUGH A CLOUD LAYER. ACFT WT 129000 LBS. THE DEVS AND CONVECTIVE ACTIVITY DID NOT SEEM TO BE ANYTHING UNUSUAL. WE STARTED TO FEEL A BUFFET AND RUMBLE. HAVING NOT FELT THAT BEFORE, AND NOT BEING CLOSE TO OUR MAX WT FOR THE ALT, THE FO AND I THOUGHT IT WAS A STRUCTURAL PROB, MAYBE A PROB WITH THE R WING. AS THE BUFFETING THE RUMBLE GOT WORSE THE ACFT WAS HAVING A HARD TIME MAINTAINING ALT AND WINGS LEVEL. THE FO KICKED OFF THE AUTOPLT AND AUTOTHROTTLES. I TOLD HER TO 'LET THE PLANE COME DOWN.' SHE LOWERED THE NOSE AND I CALLED ATC TO DECLARE AN EMER AND ASK ABOUT A SUITABLE PLACE TO LAND. AS THE PLANE WAS COMING THROUGH ABOUT FL330 I TOOK THE PLANE FROM THE FO. I ADDED SOME MORE PWR, RETRIMMED THE ACFT, AND LEVELED AT FL290. I WAS STILL HAND-FLYING THE PLANE AND IT WAS FLYING FINE. I THEN THOUGHT THE PROB WAS NOT STRUCTURAL AND THAT WE HAD APCHED A STALL. I GAVE THE PLANE BACK TO THE FO, MADE A PA, AND CALLED DISPATCH. AT NO TIME WERE THE ENGS CLOSE TO BEING OVER-BOOSTED. WE FOUND OUT LATER THAT THERE WAS MOUNTAIN WAVE ACTIVITY IN THE AREA. I THINK A COMBINATION OF MOUNTAIN WAVE, LACK OF PWR FROM ACFT ENG AND WING ANTI-ICE, AND POSSIBLE SLOW OR NO RESPONSE FROM THE AUTOTHROTTLES, CONTRIBUTED TO THIS EVENT.

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.