Small aircraft pilot encounters turbulence, declares emergency and requests ATC assistance.

Attributes
ACN	132500
Time
Date	199001
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : iyk
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla tracon : edw
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 15 flight time total : 750 flight time type : 200
ASRS Report	132500
Person 2
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Events
Anomaly	inflight encounter : weather other anomaly other
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance controller : provided flight assist flight crew : declared emergency flight crew : exited adverse environment
Consequence	Other
Supplementary
Primary Problem	Weather

Narrative:

On a VFR flight from tonopah, with complete briefing from FSS, my aircraft encountered severe turbulence over mountainous terrain east of owens lake. Moderate turbulence had been forecast. I was in contact with ZLA during the incident. The aircraft, an small aircraft, was unable to climb above the turbulence. I judged that the conditions were emergency and requested a clearance through the R2505 zone, which was initially denied, then approved. (Traversing the area on the east side of owens valley eliminated the severe conditions. The west side of the valley, where civilian aircraft are required to fly, is frequently dangerous due to the prevailing winds and mountain wave activity.) I landed the aircraft immediately at inyo-kern airport, after receiving clearance through edw approach through the portion of the restriction zone needed to remain safe during the descent. In order to continue the flight to the oxnard destination, I received a new briefing from lancaster FSS, which had just issued a SIGMET for the area, and decided to discontinue further flight. I would like to express my thanks to ZLA and eds approach for cooperating to avert an accident. I would recommend an immediate review of the boundaries of R2502, which force civilian aircraft to operate in a narrow corridor adjacent to the sierra mountains and allows for virtually no options to avoid mountain wave activity.

Original NASA ASRS Text

Title: SMA PLT ENCOUNTERS TURBULENCE, DECLARES EMERGENCY AND REQUESTS ATC ASSISTANCE.

Narrative: ON A VFR FLT FROM TONOPAH, WITH COMPLETE BRIEFING FROM FSS, MY ACFT ENCOUNTERED SEVERE TURB OVER MOUNTAINOUS TERRAIN E OF OWENS LAKE. MODERATE TURB HAD BEEN FORECAST. I WAS IN CONTACT WITH ZLA DURING THE INCIDENT. THE ACFT, AN SMA, WAS UNABLE TO CLB ABOVE THE TURB. I JUDGED THAT THE CONDITIONS WERE EMER AND REQUESTED A CLRNC THROUGH THE R2505 ZONE, WHICH WAS INITIALLY DENIED, THEN APPROVED. (TRAVERSING THE AREA ON THE E SIDE OF OWENS VALLEY ELIMINATED THE SEVERE CONDITIONS. THE W SIDE OF THE VALLEY, WHERE CIVILIAN ACFT ARE REQUIRED TO FLY, IS FREQUENTLY DANGEROUS DUE TO THE PREVAILING WINDS AND MOUNTAIN WAVE ACTIVITY.) I LANDED THE ACFT IMMEDIATELY AT INYO-KERN ARPT, AFTER RECEIVING CLRNC THROUGH EDW APCH THROUGH THE PORTION OF THE RESTRICTION ZONE NEEDED TO REMAIN SAFE DURING THE DSCNT. IN ORDER TO CONTINUE THE FLT TO THE OXNARD DEST, I RECEIVED A NEW BRIEFING FROM LANCASTER FSS, WHICH HAD JUST ISSUED A SIGMET FOR THE AREA, AND DECIDED TO DISCONTINUE FURTHER FLT. I WOULD LIKE TO EXPRESS MY THANKS TO ZLA AND EDS APCH FOR COOPERATING TO AVERT AN ACCIDENT. I WOULD RECOMMEND AN IMMEDIATE REVIEW OF THE BOUNDARIES OF R2502, WHICH FORCE CIVILIAN ACFT TO OPERATE IN A NARROW CORRIDOR ADJACENT TO THE SIERRA MOUNTAINS AND ALLOWS FOR VIRTUALLY NO OPTIONS TO AVOID MOUNTAIN WAVE ACTIVITY.

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.