Saturday, April 24, 2021

Loss of Lift: Pipistrel Sinus LSA SRL, N711MK; accident occurred April 10, 2020 in Townsend, Blount County, Tennessee

View of motor-glider from above.

Aviation Accident Final Report - National Transportation Safety Board

Additional Participating Entity:
Federal Aviation Administration / Flight Standards District Office; Nashville, Tennessee

Investigation Docket - National Transportation Safety Board:

Location: Townsend, TN
Accident Number: ERA20CA151
Date & Time: 04/10/2020, 1040 EDT
Registration: N711MK
Aircraft: Pipistrel SINUS
Aircraft Damage: Substantial
Defining Event: Loss of lift
Injuries:1 None 
Flight Conducted Under: Part 91: General Aviation - Personal


The pilot reported that, while en route, the motor glider began to lose altitude unexpectedly. He turned the motor glider toward an area where lift was expected, but it continued to descend. When the motor glider was about 300 ft above trees, he unfeathered the propeller and started the engine. The motor glider continued to descend due to a downdraft, and the pilot deployed the airframe parachute. Subsequently, the motor glider impacted vegetation, which resulted in substantial damage to both wings and the fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the motor 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 motor glider's encounter with atmospheric lift conditions that were not sufficient to maintain flight, which necessitated a forced landing and resulted in impact with vegetation. Contributing to the accident was the pilot's delayed decision to restart the motor glider's engine.


Environmental issues Thermal lifting - Effect on equipment
Aircraft Altitude - Not attained/maintained
Environmental issues Tree(s) - Effect on operation
Personnel issues Delayed action - Pilot

Factual Information

History of Flight

Maneuvering-low-alt flying Loss of lift (Defining event)
Maneuvering-low-alt flying Attempted remediation/recovery
Landing Off-field or emergency landing
Maneuvering-low-alt flying Collision with terr/obj (non-CFIT)

Pilot Information

Certificate: Private; Sport Pilot
Age: 47, Male
Airplane Rating(s): Single-engine Land
Seat Occupied: Right
Other Aircraft Rating(s): Glider
Restraint Used:
Instrument Rating(s): None
Second Pilot Present: No
Instructor Rating(s): None
Toxicology Performed: No
Medical Certification: Class 3 Without Waivers/Limitations
Last FAA Medical Exam: 09/27/2017
Occupational Pilot: No
Last Flight Review or Equivalent: 12/26/2019
Flight Time:  (Estimated) 1210 hours (Total, all aircraft), 1043 hours (Total, this make and model), 1125 hours (Pilot In Command, all aircraft), 17 hours (Last 90 days, all aircraft), 7 hours (Last 30 days, all aircraft) 

Aircraft and Owner/Operator Information

Aircraft Make: Pipistrel
Registration: N711MK
Model/Series: SINUS No Series
Aircraft Category: Airplane
Year of Manufacture: 2013
Amateur Built: No
Airworthiness Certificate: Special Light-Sport
Serial Number: 510 SN 912 LSA
Landing Gear Type: Tricycle
Date/Type of Last Inspection: 09/21/2019, Annual
Certified Max Gross Wt.: 1212 lbs
Time Since Last Inspection:
Engines: 1 Reciprocating
Airframe Total Time: 1046 Hours at time of accident
Engine Manufacturer: Rotax
ELT:C126 installed 
Engine Model/Series: 912 UL2
Registered Owner: On file
Rated Power:80 hp 
Operator: On file
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual Conditions
Condition of Light: Day
Observation Facility, Elevation: 1A5, 2020 ft msl
Distance from Accident Site: 22 Nautical Miles
Observation Time: 1035 EDT
Direction from Accident Site: 159°
Lowest Cloud Condition: Clear
Visibility:  10 Miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: Calm /
Turbulence Type Forecast/Actual: None / Terrain-Induced
Wind Direction:
Turbulence Severity Forecast/Actual: N/A / Moderate
Altimeter Setting: 30.16 inches Hg
Temperature/Dew Point: 9°C / -3°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Atlanta, GA (RYY)
Type of Flight Plan Filed: None
Destination: Atlanta, GA (RYY)
Type of Clearance: None
Departure Time: 0900 EDT
Type of Airspace: Class G 

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries: N/A
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None
Latitude, Longitude: 35.570833, -83.585000 (est)

No comments:

Post a Comment