Thursday, December 30, 2021

Loss of Lift: Glasflugel 304 CZ-17, N974CQ; accident occurred June 20, 2021 in Winthrop, Okanogan County, Washington

Aviation Accident Final Report - National Transportation Safety Board

The National Transportation Safety Board did not travel to the scene of this accident. 

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Spokane, Washington
Location: Winthrop, Washington
Accident Number: WPR21LA235
Date and Time: June 20, 2021, 15:16 Local 
Registration: N974CQ
Aircraft Damage: Substantial
Defining Event: Loss of lift 
Injuries: 1 Minor
Flight Conducted Under: Part 91: General aviation - Personal


The glider pilot reported that after an uneventful tow to 4,000 ft msl (about 2,300 ft agl), he proceeded to fly north with the intention of reaching a mountain peak about 40 miles away. Soaring conditions were good, and the glider had climbed to about 10,500 ft msl by the time he reached a peak at the halfway point. On the second leg, the glider started to encounter sink, and the pilot continued to fly along mountain ridges to regain altitude. The pilot managed to climb the glider back to 8,000 ft, but again began to encounter sink and decided to work along mountain ridges back to the south with the intention of landing at an intermediary airport. He was not able to maintain altitude, and ultimately decided to perform an off-airport landing into a valley clearing. During the landing roll the right wing was substantially damaged when it struck a tree. The pilot reported that there were no mechanical failures or malfunctions with the glider that would have precluded normal operation.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
The glider’s encounter with atmospheric conditions where the lift was not sufficient to maintain flight. 


Environmental issues Thermal lifting - Effect on operation
Aircraft Altitude - Attain/maintain not possible

Factual Information

History of Flight

Enroute Loss of lift (Defining event)
Landing Off-field or emergency landing
Landing Collision with terr/obj (non-CFIT)

Pilot Information

Certificate: Commercial; Flight instructor 
Age: 47, Male
Airplane Rating(s): Single-engine land 
Seat Occupied: Single
Other Aircraft Rating(s): Glider
Restraint Used: 5-point
Instrument Rating(s): Airplane
Second Pilot Present:
Instructor Rating(s): Airplane single-engine 
Toxicology Performed:
Medical Certification: None 
Last FAA Medical Exam:
Occupational Pilot: No
Last Flight Review or Equivalent: May 28, 2020
Flight Time: 1606.9 hours (Total, all aircraft), 148.5 hours (Total, this make and model), 1595.5 hours (Pilot In Command, all aircraft)

Aircraft and Owner/Operator Information

Aircraft Make: HPH LTD 
Registration: N974CQ
Model/Series: GLASFLUGEL 304CZ-17 
Aircraft Category: Glider
Year of Manufacture: 2001
Amateur Built:
Airworthiness Certificate: Other
Serial Number: 43-17
Landing Gear Type: Retractable - ; Other launch/recovery system
Seats: 1
Date/Type of Last Inspection: August 1, 2020 Annual 
Certified Max Gross Wt.: 992 lbs
Time Since Last Inspection: 20 Hrs Engines: 0
Airframe Total Time: at time of accident 
Engine Manufacturer:
ELT: Not installed 
Engine Model/Series:
Registered Owner:
Rated Power:
Operator: On file 
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual (VMC) 
Condition of Light: Day
Observation Facility, Elevation: KOMK, 1300 ft msl
Distance from Accident Site: 27 Nautical Miles
Observation Time: 14:53 Local 
Direction from Accident Site: 111°
Lowest Cloud Condition: Clear 
Visibility: 10 miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 7 knots /
Turbulence Type Forecast/Actual:  /
Wind Direction: 200° 
Turbulence Severity Forecast/Actual:  /
Altimeter Setting: 29.65 inches Hg
Temperature/Dew Point: 44°C / 9°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Twisp, WA (2S0)
Type of Flight Plan Filed: Military VFR
Destination: Winthrop, WA 
Type of Clearance: None
Departure Time: 12:49 Local
Type of Airspace: Class E

Wreckage and Impact Information

Crew Injuries: 1 Minor 
Aircraft Damage: Substantial
Passenger Injuries:
Aircraft Fire: None
Ground Injuries: 
Aircraft Explosion: None
Total Injuries: 1 Minor
Latitude, Longitude: 48.625833,-120.1545 (est)

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