Sunday, January 31, 2021

Abnormal Runway Contact: Pipistrel Sinus 912, N783TH; accident occurred June 13, 2020 at Brookline Airport (NH16), Hillsborough County, New Hampshire

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; Portland, Maine

Investigation Docket - National Transportation Safety Board:

Location: Brookline, New Hampshire 
Accident Number: ERA20CA215
Date & Time: June 13, 2020, 16:30 Local
Registration: N783TH
Aircraft: Pipistrel PIPISTREL SINUS 912 
Aircraft Damage: Substantial
Defining Event: Abnormal runway contact
Injuries: 1 None
Flight Conducted Under: Part 91: General aviation - Personal


The pilot of the experimental, amateur-built motor glider was landing on a 1,926-ft-long, 24-ft wide runway with about a 6 knot quartering tailwind. During his first attempted landing the motor glider was high and fast on approach and the pilot elected to go-around. During his second attempt, the motor glider was also high and fast but the pilot elected to continue the approach to landing, using full air brakes and wing flaps. During the approach, he slowed the motor glider to 40 knots (6 knots above stall speed), and the motor glider then seemed to drop from about 10 ft above the runway and land hard. The right landing gear leg collapsed, and the motor glider veered off the right side of the runway, struck a vertical approach slope indicator, and was substantially damaged. Review of the Pilot's Operating Handbook revealed that the final approach speed should always be 55 knots with full flaps regardless of approaching with zero or full airbrakes. The pilot reported that there were no preimpact mechanical malfunctions or failures 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 pilot's failure to maintain airspeed while landing with a quartering tailwind, which resulted in a loss of control and a hard landing.


Aircraft Landing flare - Not attained/maintained
Personnel issues Aircraft control - Pilot
Environmental issues Tailwind - Effect on operation

Factual Information

History of Flight

Landing-flare/touchdown Abnormal runway contact (Defining event)
Landing-landing roll Runway excursion
Landing-landing roll Collision with terr/obj (non-CFIT)

Pilot Information

Certificate: Private 
Age: 79, Male
Airplane Rating(s): Single-engine land
Seat Occupied: Left
Other Aircraft Rating(s): Glider 
Restraint Used: 4-point
Instrument Rating(s): None
Second Pilot Present: No
Instructor Rating(s): None 
Toxicology Performed: No
Medical Certification: Class 3 With waivers/limitations Last FAA Medical Exam: June 7, 2018
Occupational Pilot: No
Last Flight Review or Equivalent: September 20, 2018
Flight Time: 770 hours (Total, all aircraft), 10 hours (Total, this make and model)

Aircraft and Owner/Operator Information

Aircraft Make: Pipistrel 
Registration: N783TH
Model/Series: PIPISTREL SINUS 912 No Series
Aircraft Category: Glider
Year of Manufacture: 2019 
Amateur Built: Yes
Airworthiness Certificate: Experimental (Special)
Serial Number: 467 S 912 KIT
Landing Gear Type: Tailwheel 
Seats: 2
Date/Type of Last Inspection: July 12, 2019 Condition
Certified Max Gross Wt.: 1210 lbs
Time Since Last Inspection: 10 Hrs
Engines: 1 Reciprocating
Airframe Total Time: 10 Hrs at time of accident 
Engine Manufacturer: Rotax
ELT: C126 installed, activated, did not aid in locating accident
Engine Model/Series: 912 UL2
Registered Owner:
Rated Power: 80 Horsepower
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: KASH,200 ft msl 
Distance from Accident Site: 9 Nautical Miles
Observation Time: 15:56 Local
Direction from Accident Site: 73°
Lowest Cloud Condition: 
Visibility: 10 miles
Lowest Ceiling: Overcast / 7500 ft
AGL Visibility (RVR):
Wind Speed/Gusts: 9 knots / 
Turbulence Type Forecast/Actual: None / None
Wind Direction: 320° 
Turbulence Severity Forecast/Actual: N/A / N/A
Altimeter Setting: 30.15 inches Hg
Temperature/Dew Point: 22°C / 4°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Brookline, NH (NH16)
Type of Flight Plan Filed: None
Destination: Brookline, NH (NH16)
Type of Clearance: None
Departure Time: 15:30 Local 
Type of Airspace: Class G

Airport Information

Airport: Brookline NH16
Runway Surface Type: Asphalt
Airport Elevation: 415 ft msl 
Runway Surface Condition: Dry
Runway Used: 19 
IFR Approach: None
Runway Length/Width: 1926 ft / 24 ft
VFR Approach/Landing: Full stop;Traffic pattern

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries:
Aircraft Fire: None
Ground Injuries: N/A
Aircraft Explosion: None
Total Injuries: 1 None 
Latitude, Longitude: 42.741664,-71.707496(est)

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