Aircraft Accident/Incident Report

Grass Valley, California 95945
Tuesady, July 4, 2000 11:45 PDT

NTSB Narrative Summary Released at Completion of Accident

The pilot was cruising the local area about 1,000 feet agl, at 2,500 rpm, when the airplane suddenly started to descend. Although he hadn't noticed any evidence of strong winds, he was on the lee side of a peak. He turned to avoid the wind shear and applied full power, but his descent continued. The airplane collided with 100-feet tall trees after he maneuvered to avoid hitting one straight on with the cabin area.

NTSB Probable Cause Narrative

the pilot encountered a mountain wave at an altitude too low to maintain clearance from trees.

Event Information

Type of Event Accident
Event Date 7/4/2000
Event Day of the Week Tuesday
Time of Event 1145
Event Time Zone Pacific Daylight Time
Event City GRASS VALLEY
Event State CALIFORNIA
Event Country --
Zipcode of the event site 95945
Event Date Year 2000
Event Date Month 7
MidAir Collision Indicator No
On Ground Collision occurred ? No
Event Location Latitude --
Event Location Longitude --
Event Location Airport
Event Location Nearest Airport ID
Indicates whether the acc/inc occurred off or on an airport Off Airport/Airstrip
Distance from airport in statute miles --
Degrees magnetic from airport --
Airport Elevation --
Weather Briefing Completeness Not pertinent
Investigator's weather source Weather Observation Facility
Time of the weather observation 1152 Pacific Daylight Time
Direction of event from weather observation facility (degrees) 60
Weather Observation Facility ID BLU
Elevation of weather observation facility 5284
Distance of event from weather observation facility (units?) 14
Time Zone of the weather observation PDT
Lighting Conditions Day
Lowest Ceiling Height 0
Lowest Non-Ceiling Height 0
Sky/Lowest/Cloud Conditions Clear
Sky Condition for Lowest Ceiling None
Visibility Runway Visual Range (Feet) 0
Visibility Runway Visual Value (Statute Miles) 0
Visibility (Statute Miles) 10
Air Temperature at event time (in degrees celsius) 61
Dew Point at event time (in degress fahrenheit) 39
Wind Direction (degrees magnetic) 0
Variable Wind Indicator Unknown
Wind Speed (knots) 6
Wind Velocity Indicator Unknown
Wind Gust Indicator Not Gusting
Wind Gust (knots) 0
Altimeter Setting at event time (in. Hg) 30
Density Altitude (feet) --
Intensity of Precipitation Unknown
METAR weather report --
Event Highest Injury Serious
On Ground, Fatal Injuries 0
On Ground, Minor Injuries 0
On Ground, Serious Injuries 0
Injury Total Fatal --
Injury Total Minor --
Injury Total None --
Injury Total Serious 2
Injury Total All 2
Investigating Agency NTSB
NTSB Docket Number (internal use) 10739
NTSB Notification Source FAA
NTSB Notification Date Jul 4 2000 12:00AM
NTSB Notification Time 1310
Fiche Number and/or location -used to find docket information IMAGE
Date of most recent change to record Oct 17 2001 9:02AM
User who most recently changed record NTSB\MONR
Basic weather conditions Visual Meteorological Cond
FAA District Office --

Aircraft Involved

Aircraft #1

Aircraft Registration Number N91313
NTSB Number LAX00LA250
Missing Aircraft Indicator N
Federal Aviation Reg. Part Part 91: General Aviation
Type of Flight Plan filed None
Flight plan Was Activated? --
Damage Substantial
Aircraft Fire None
Aircraft Explosion None
Aircraft Manufacturer's Full Name Thorp
Aircraft Model T211
Aircraft Series Identifier T211
Aircraft Serial Number 4
Certified Max Gross Weight 1270
Aircraft Category Airplane
Aircraft Registration Class U.S. Registered/U.S. Soil
Aircraft is a homebuilt? No
Flight Crew Seats --
Cabin Crew Seats --
Passenger Seats --
Total number of seats on the aircraft 2
Number of Engines 1
Fixed gear or retractable gear Fixed
Aircraft, Type of Last Inspection Annual
Date of Last Inspection Nov 12 1999 12:00AM
Airframe hours since last inspection 5
Airframe Hours 1255
ELT Installed Yes
ELT Activated Yes
ELT Aided Location of Event Site No
ELT Type --
Aircraft Owner Name ROBERT L RIDDLE
Aircraft Owner Street Address
Aircraft Owner City GRASS VALLEY
Aircraft Owner State CA
Aircraft Owner Country
Aircraft Owner Zipcode 95949
Operator is an individual? --
Operator Name
Operator Same as Owner? Yes
Operator Is Doing Business As --
Operator Address Same as Owner? Yes
Operator Street Address
Operator City
Operator State
Operator Country
Operator Zip code
Operator Code
Owner has at least one certificate None
Other Operator of large aircraft? No
Certified for Part 133 or 137 Operation Unknown
Operator Certificate Number --
Indicates whether an air carrier operation was scheduled or not --
Indicates Domestic or International Flight --
Operator carrying Pax/Cargo/Mail --
Type of Flying (Per_Bus / Primary) Personal
Second Pilot on Board No
Departure Point Same as Event No
Departure Airport Code AUN
Departure City AUBURN
Departure State CA
Departure Country
Departure Time 1130
Departure Time Zone PDT
Destination Same as Local Flt --
Destination Airport Code Q62
Destination City ALTA VISTA
Destination State CA
Destination Country
Specific Phase of Flight Cruise
Report sent to ICAO? --
Evacuation occurred --
Date of most recent change to record Sep 26 2001 4:00AM
User who most recently changed record dbo
Since inspection or accident --
Event Location Runway Number and Location 0
Runway Length --
Runway Width --
Sight Seeing flight No
Air Medical Flight No
Medical Flight --