Small aircraft pilot had aircraft upset in IMC during turbulence encounter.

Attributes
ACN	401651
Time
Date	199805
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mxw
State Reference	CA
Altitude	msl bound lower : 6000 msl bound upper : 16000
Environment
Flight Conditions	IMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zoa tower : sus
Operator	general aviation : personal
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Route In Use	enroute airway : v87
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : single pilot oversight : pic
Qualification	other other : other pilot : instrument pilot : commercial
Experience	flight time last 90 days : 90 flight time total : 475 flight time type : 50
ASRS Report	401651
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	aircraft equipment problem : critical altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	controller : provided flight assist controller : issued new clearance flight crew : declared emergency flight crew : regained aircraft control other
Consequence	other Other
Supplementary
Primary Problem	Aircraft

Narrative:

Encountered turbulence while flying at 16000 ft with autoplt and in IMC. After turbulence, noise increased and viewed artificial horizon tumbling, airspeed increasing and losing altitude. Tried recovery and eventually gained control after losing 9000-10000 ft. After this tried to climb over IMC and asked for new vector. Given vector to williams. Discovered directional gyro (his) non functional. Asked for nearest airport and chose napa. Given no gyro headings and landed in napa. Inspected aircraft and felt to be flyable and flew to hayward.

Original NASA ASRS Text

Title: SMA PLT HAD ACFT UPSET IN IMC DURING TURB ENCOUNTER.

Narrative: ENCOUNTERED TURB WHILE FLYING AT 16000 FT WITH AUTOPLT AND IN IMC. AFTER TURB, NOISE INCREASED AND VIEWED ARTIFICIAL HORIZON TUMBLING, AIRSPD INCREASING AND LOSING ALT. TRIED RECOVERY AND EVENTUALLY GAINED CTL AFTER LOSING 9000-10000 FT. AFTER THIS TRIED TO CLB OVER IMC AND ASKED FOR NEW VECTOR. GIVEN VECTOR TO WILLIAMS. DISCOVERED DIRECTIONAL GYRO (HIS) NON FUNCTIONAL. ASKED FOR NEAREST ARPT AND CHOSE NAPA. GIVEN NO GYRO HEADINGS AND LANDED IN NAPA. INSPECTED ACFT AND FELT TO BE FLYABLE AND FLEW TO HAYWARD.

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.