MD80 flight crew encounters severe turbulence with altdevs of plus or minus 3000 ft.

Attributes
ACN	693214
Time
Date	200604
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : enl.vortac
State Reference	FL
Altitude	msl single value : 33000
Environment
Weather Elements	Windshear Thunderstorm other
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zkc.artcc
Operator	common carrier : air carrier
Make Model Name	MD-80 Series (DC-9-80) Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	693214
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
ASRS Report	693213
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : turbulence
Independent Detector	other flight crewa other flight crewb
Resolutory Action	flight crew : exited adverse environment
Consequence	faa : reviewed incident with flight crew other
Supplementary
Problem Areas	Environmental Factor Weather Aircraft
Primary Problem	Environmental Factor

Narrative:

In the area of enl; FL330; while deviating around large buildups; we encountered severe turbulence. We advise ATC of severe turbulence and that we were not able to hold altitude. ATC issued FL290; then issued altdevs permissible hold FL290 when able. Communication with ATC at this time was made difficult due to static on ATC frequency. We encountered several u- and downdrafts with altdevs of +/-3000 ft. Severe turbulence lasted for about 3 mins. For about the last min; while in the severe turbulence; the cabin crew reported hearing a banging noise from the right engine (approximately 10 bangs). We observed no unusual engine indications from the cockpit. The remainder of the flight we encountered light turbulence to smooth ride conditions. Upon arrival at lga; we made E-6 entries for severe turbulence as well as possible engine compressor stall condition.

Original NASA ASRS Text

Title: MD80 FLT CREW ENCOUNTERS SEVERE TURB WITH ALTDEVS OF PLUS OR MINUS 3000 FT.

Narrative: IN THE AREA OF ENL; FL330; WHILE DEVIATING AROUND LARGE BUILDUPS; WE ENCOUNTERED SEVERE TURB. WE ADVISE ATC OF SEVERE TURB AND THAT WE WERE NOT ABLE TO HOLD ALT. ATC ISSUED FL290; THEN ISSUED ALTDEVS PERMISSIBLE HOLD FL290 WHEN ABLE. COM WITH ATC AT THIS TIME WAS MADE DIFFICULT DUE TO STATIC ON ATC FREQ. WE ENCOUNTERED SEVERAL U- AND DOWNDRAFTS WITH ALTDEVS OF +/-3000 FT. SEVERE TURB LASTED FOR ABOUT 3 MINS. FOR ABOUT THE LAST MIN; WHILE IN THE SEVERE TURB; THE CABIN CREW RPTED HEARING A BANGING NOISE FROM THE R ENG (APPROX 10 BANGS). WE OBSERVED NO UNUSUAL ENG INDICATIONS FROM THE COCKPIT. THE REMAINDER OF THE FLT WE ENCOUNTERED LIGHT TURB TO SMOOTH RIDE CONDITIONS. UPON ARR AT LGA; WE MADE E-6 ENTRIES FOR SEVERE TURB AS WELL AS POSSIBLE ENG COMPRESSOR STALL CONDITION.

Data retrieved from NASA's ASRS site as of January 2009 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.