Iai-1124 crew experiences turbulence at FL340 over elp and loses altitude.

Attributes
ACN	714871
Time
Date	200610
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : elp.vortac
State Reference	TX
Altitude	msl single value : 34000
Environment
Flight Conditions	VMC
Weather Elements	Turbulence
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zab.artcc
Operator	general aviation : corporate
Make Model Name	IAI1124/1124A/Westwind
Operating Under FAR Part	Part 91
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 58 flight time total : 6832 flight time type : 3100
ASRS Report	714871
Person 2
Affiliation	company : corporate
Function	flight crew : first officer
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 70 flight time total : 1800 flight time type : 40
ASRS Report	715207
Events
Anomaly	aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude inflight encounter : turbulence
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to assigned altitude
Supplementary
Problem Areas	Aircraft Weather
Primary Problem	Weather

Narrative:

We were in cruise flight at FL340 in vicinity of elp VOR. We had been experiencing moderate continuous turbulence and chop for about 20 mins when we hit an isolated pocket of moderate/severe turbulence. The aircraft went into an uncontrolled bank and descent. I assumed control of aircraft by leveling the wings; then abated the descent. We immediately notified ATC of our situation and leveled off at FL340. The whole time-frame was approximately 5-7 seconds. I reengaged autoplt and it performed correctly. We slowed aircraft further until clear of turbulence. (We were flying at va for our weight; 204 KTS/17500 pounds.) we resumed normal flight after checking autoplt. I had maintenance look at autoplt upon landing. The total amount of altitude lost was between 300-350 ft. A company incident report was also filed.

Original NASA ASRS Text

Title: IAI-1124 CREW EXPERIENCES TURB AT FL340 OVER ELP AND LOSES ALT.

Narrative: WE WERE IN CRUISE FLT AT FL340 IN VICINITY OF ELP VOR. WE HAD BEEN EXPERIENCING MODERATE CONTINUOUS TURB AND CHOP FOR ABOUT 20 MINS WHEN WE HIT AN ISOLATED POCKET OF MODERATE/SEVERE TURB. THE ACFT WENT INTO AN UNCTLED BANK AND DSCNT. I ASSUMED CTL OF ACFT BY LEVELING THE WINGS; THEN ABATED THE DSCNT. WE IMMEDIATELY NOTIFIED ATC OF OUR SITUATION AND LEVELED OFF AT FL340. THE WHOLE TIME-FRAME WAS APPROX 5-7 SECONDS. I REENGAGED AUTOPLT AND IT PERFORMED CORRECTLY. WE SLOWED ACFT FURTHER UNTIL CLR OF TURB. (WE WERE FLYING AT VA FOR OUR WT; 204 KTS/17500 LBS.) WE RESUMED NORMAL FLT AFTER CHKING AUTOPLT. I HAD MAINT LOOK AT AUTOPLT UPON LNDG. THE TOTAL AMOUNT OF ALT LOST WAS BTWN 300-350 FT. A COMPANY INCIDENT RPT WAS ALSO FILED.

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.