Narrative:

Incident took place during a flight from acy to clt. Upon arrival at the airport for my flight from dtw, my release and WX package agreed with my prior information. PIREPS by B757, B737, DC9, etc, reported severe turbulence above FL180 for my area of flight that the flight would pass. As we approached harrisburg en route to acy, we were slowed to 250 KTS due to traffic saturation into phl. I queried ATC and he stated that due to the rough rides above FL180 everyone was down low, including traffic normally at FL290 and above. Again, more advance knowledge of WX we would encounter from acy to clt. Flight pushed and departed for clt. We were filed for FL240 and climbed to 16000 ft just north of bwi. I asked my first officer to query when we might get higher. The approach controller at dca said he assumed we would not want to go higher due to all the encounters with severe turbulence by other aircraft. Since flight plan fuel burn was 8340 pounds at FL240 and we were carrying 24600 pounds, I chose to take his advice. About 45 mins out of acy, somewhere near or south of gve VOR, I noticed my airspeed go from 310 KIAS to 340 KIAS in about 5-10 seconds. Since 340 KIAS was 'red' line I reduced power so as not to overspd, at the same time trying to figure out what was happening as the flight was in smooth air. As soon as my airspeed began to settle down it just as abruptly lost 30 KTS and was dropping to 280 KIAS. At that point I added power and we entered an area of severe turbulence, initially causing the aircraft to climb +600 ft to 14600 ft, at which point the autoplt disengaged. With hands ready, I assumed control of the aircraft and reduced power, pushing the nose over to descend, simultaneously I called ATC (either dca or atl). 'Center xyz.' ATC came back, 'check your altitude.' 'center xyz is in severe turbulence and we want an immediate descent to 14000 ft.' ATC, 'descend now to 14000 ft, turn right to 270 degrees for your descent.' at that point I asked the first officer to make an announcement and get the flight attendants seated. As I started my turn to 270 degrees I attempted to descend but found it difficult to do, even at 1.1 EPR due to what must have been a wave associated with the jetstream. After about 3 mins we were level at 14000 ft and the air was again smooth. Our encounter with the turbulence lasted about 30 seconds causing the altitude to change +/-600 ft from our assigned altitude of 16000 ft. Approximately 3-5 mins behind us was another airliner at 16000 ft following us south on the same ATC frequency as our flight. They came on the air and said they too had encountered the same turbulence and too wanted to descend to 14000 ft.

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Original NASA ASRS Text

Title: FLC OF MLG REMAINS AT LOW ALT DUE TO SEVERE TURB HIGHER. THEY STILL ENCOUNTER UPDRAFTS AND DOWNDRAFTS AND REQUEST STILL LOWER. ATC CLRS LOWER AND TURNS THEM FOR TFC.

Narrative: INCIDENT TOOK PLACE DURING A FLT FROM ACY TO CLT. UPON ARR AT THE ARPT FOR MY FLT FROM DTW, MY RELEASE AND WX PACKAGE AGREED WITH MY PRIOR INFO. PIREPS BY B757, B737, DC9, ETC, RPTED SEVERE TURB ABOVE FL180 FOR MY AREA OF FLT THAT THE FLT WOULD PASS. AS WE APCHED HARRISBURG ENRTE TO ACY, WE WERE SLOWED TO 250 KTS DUE TO TFC SATURATION INTO PHL. I QUERIED ATC AND HE STATED THAT DUE TO THE ROUGH RIDES ABOVE FL180 EVERYONE WAS DOWN LOW, INCLUDING TFC NORMALLY AT FL290 AND ABOVE. AGAIN, MORE ADVANCE KNOWLEDGE OF WX WE WOULD ENCOUNTER FROM ACY TO CLT. FLT PUSHED AND DEPARTED FOR CLT. WE WERE FILED FOR FL240 AND CLBED TO 16000 FT JUST N OF BWI. I ASKED MY FO TO QUERY WHEN WE MIGHT GET HIGHER. THE APCH CTLR AT DCA SAID HE ASSUMED WE WOULD NOT WANT TO GO HIGHER DUE TO ALL THE ENCOUNTERS WITH SEVERE TURB BY OTHER ACFT. SINCE FLT PLAN FUEL BURN WAS 8340 LBS AT FL240 AND WE WERE CARRYING 24600 LBS, I CHOSE TO TAKE HIS ADVICE. ABOUT 45 MINS OUT OF ACY, SOMEWHERE NEAR OR S OF GVE VOR, I NOTICED MY AIRSPD GO FROM 310 KIAS TO 340 KIAS IN ABOUT 5-10 SECONDS. SINCE 340 KIAS WAS 'RED' LINE I REDUCED PWR SO AS NOT TO OVERSPD, AT THE SAME TIME TRYING TO FIGURE OUT WHAT WAS HAPPENING AS THE FLT WAS IN SMOOTH AIR. AS SOON AS MY AIRSPD BEGAN TO SETTLE DOWN IT JUST AS ABRUPTLY LOST 30 KTS AND WAS DROPPING TO 280 KIAS. AT THAT POINT I ADDED PWR AND WE ENTERED AN AREA OF SEVERE TURB, INITIALLY CAUSING THE ACFT TO CLB +600 FT TO 14600 FT, AT WHICH POINT THE AUTOPLT DISENGAGED. WITH HANDS READY, I ASSUMED CTL OF THE ACFT AND REDUCED PWR, PUSHING THE NOSE OVER TO DSND, SIMULTANEOUSLY I CALLED ATC (EITHER DCA OR ATL). 'CTR XYZ.' ATC CAME BACK, 'CHK YOUR ALT.' 'CTR XYZ IS IN SEVERE TURB AND WE WANT AN IMMEDIATE DSCNT TO 14000 FT.' ATC, 'DSND NOW TO 14000 FT, TURN R TO 270 DEGS FOR YOUR DSCNT.' AT THAT POINT I ASKED THE FO TO MAKE AN ANNOUNCEMENT AND GET THE FLT ATTENDANTS SEATED. AS I STARTED MY TURN TO 270 DEGS I ATTEMPTED TO DSND BUT FOUND IT DIFFICULT TO DO, EVEN AT 1.1 EPR DUE TO WHAT MUST HAVE BEEN A WAVE ASSOCIATED WITH THE JETSTREAM. AFTER ABOUT 3 MINS WE WERE LEVEL AT 14000 FT AND THE AIR WAS AGAIN SMOOTH. OUR ENCOUNTER WITH THE TURB LASTED ABOUT 30 SECONDS CAUSING THE ALT TO CHANGE +/-600 FT FROM OUR ASSIGNED ALT OF 16000 FT. APPROX 3-5 MINS BEHIND US WAS ANOTHER AIRLINER AT 16000 FT FOLLOWING US S ON THE SAME ATC FREQ AS OUR FLT. THEY CAME ON THE AIR AND SAID THEY TOO HAD ENCOUNTERED THE SAME TURB AND TOO WANTED TO DSND TO 14000 FT.

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.