B757 crew encountered moderate to severe turbulence in ZDC class a airspace.

Attributes
ACN	484600
Time
Date	200009
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : iad.airport
State Reference	VA
Altitude	msl bound lower : 22000 msl bound upper : 22300
Environment
Flight Conditions	IMC
Weather Elements	Turbulence
Light	Dusk
Aircraft 1
Controlling Facilities	artcc : zdc.artcc tower : dsm.tower
Operator	common carrier : air carrier
Make Model Name	B757-200
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude
Flight Plan	IFR
Person 1
Qualification	pilot : atp pilot : commercial pilot : multi engine
Experience	flight time total : 5600 flight time type : 280
ASRS Report	484600
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : turbulence inflight encounter : weather inflight encounter other non adherence : company policies non adherence : published procedure other anomaly other
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : returned to assigned altitude none taken : detected after the fact none taken : insufficient time
Consequence	other
Supplementary
Problem Areas	Aircraft Weather
Primary Problem	Weather

Narrative:

While flying at FL220 straight and level, aircraft entered IMC. Continuous light chop had been the norm for most of the flight from atl to iad. WX radar showed no returns for at least 40 NM and those thunderstorms were scattered and visible when in the clear. While flying in what appeared to be stratiform clouds, aircraft suddenly and violently encountered gusts, moderate precipitation and moderate turbulence. Only 1 downdraft encountered, but it caused a zero-G situation. Aircraft was flying at 290 KIAS (turbulence air penetration speed) when the nose pitched up during downdraft and started climbing. Autoplt was unable to counter the pitch up, so I disconnected the autoplt and pushed the nose down smoothly to recapture FL220. Aircraft climbed approximately 300 ft during the turbulence encounter. Entire evolution took approximately 20 seconds from the first turbulence bump to the last.

Original NASA ASRS Text

Title: B757 CREW ENCOUNTERED MODERATE TO SEVERE TURB IN ZDC CLASS A AIRSPACE.

Narrative: WHILE FLYING AT FL220 STRAIGHT AND LEVEL, ACFT ENTERED IMC. CONTINUOUS LIGHT CHOP HAD BEEN THE NORM FOR MOST OF THE FLT FROM ATL TO IAD. WX RADAR SHOWED NO RETURNS FOR AT LEAST 40 NM AND THOSE TSTMS WERE SCATTERED AND VISIBLE WHEN IN THE CLR. WHILE FLYING IN WHAT APPEARED TO BE STRATIFORM CLOUDS, ACFT SUDDENLY AND VIOLENTLY ENCOUNTERED GUSTS, MODERATE PRECIP AND MODERATE TURB. ONLY 1 DOWNDRAFT ENCOUNTERED, BUT IT CAUSED A ZERO-G SIT. ACFT WAS FLYING AT 290 KIAS (TURB AIR PENETRATION SPD) WHEN THE NOSE PITCHED UP DURING DOWNDRAFT AND STARTED CLBING. AUTOPLT WAS UNABLE TO COUNTER THE PITCH UP, SO I DISCONNECTED THE AUTOPLT AND PUSHED THE NOSE DOWN SMOOTHLY TO RECAPTURE FL220. ACFT CLBED APPROX 300 FT DURING THE TURB ENCOUNTER. ENTIRE EVOLUTION TOOK APPROX 20 SECONDS FROM THE FIRST TURB BUMP TO THE LAST.

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.