Air carrier flight crew of medium large transport loses altitude in nearly severe turbulence near ds...

Attributes
ACN	426130
Time
Date	199901
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : dsm
State Reference	IA
Altitude	msl bound lower : 32300 msl bound upper : 33000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial
Experience	flight time last 90 days : 210 flight time total : 3500 flight time type : 810
ASRS Report	426130
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	altitude deviation : excursion from assigned altitude
Independent Detector	atc equipment other atc equipment : unspecified aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Air Traffic Incident	other

Narrative:

FL280 and wanted to climb to a higher altitude to find smoother air. We requested FL390 and given the climb to FL330 we encountered almost severe turbulence and lost airspeed. To maintain airspeed we had to push the nose over and we ended up at FL323. While the copilot was trying to get a descent clearance to lower altitude, ATC was yelling about our descent. We were able to climb back to FL330 and eventually were cleared to a lower altitude. Radios were very jammed at the time of the occurrence and we were unable to tell ATC what was happening for approximately 45 seconds. Wind speed at altitude went from 120 KTS to 112 KTS very quickly.

Original NASA ASRS Text

Title: ACR FLC OF MLG LOSES ALT IN NEARLY SEVERE TURB NEAR DSM.

Narrative: FL280 AND WANTED TO CLB TO A HIGHER ALT TO FIND SMOOTHER AIR. WE REQUESTED FL390 AND GIVEN THE CLB TO FL330 WE ENCOUNTERED ALMOST SEVERE TURB AND LOST AIRSPD. TO MAINTAIN AIRSPD WE HAD TO PUSH THE NOSE OVER AND WE ENDED UP AT FL323. WHILE THE COPLT WAS TRYING TO GET A DSCNT CLRNC TO LOWER ALT, ATC WAS YELLING ABOUT OUR DSCNT. WE WERE ABLE TO CLB BACK TO FL330 AND EVENTUALLY WERE CLRED TO A LOWER ALT. RADIOS WERE VERY JAMMED AT THE TIME OF THE OCCURRENCE AND WE WERE UNABLE TO TELL ATC WHAT WAS HAPPENING FOR APPROX 45 SECONDS. WIND SPD AT ALT WENT FROM 120 KTS TO 112 KTS VERY QUICKLY.

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.

Air carrier flight crew of medium large transport loses altitude in nearly severe turbulence near dsm.