- Date
- July 3, 2010, 12:00 local (18:00 UTC)
- Place
- Wellington, CO
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Takeoff
- Aircraft
- N301TWWells Terry Hula Girl
- Defining event
- Takeoff: Loss of engine power (partial)
- Weather
- Visual (VMC) · Day
- Status
- Completed · report October 21, 2010
- Report
- Approved by Office Director
- NTSB office
- Central Region
- Parties
- FAA Denver FSDO
- FAA report
- 20100703038609A
- Case key
- 76556
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
A partial loss of engine power due to the inadequate design of the engine cowling.
Findings · 1
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
The pilot, who is also the designer and builder of the experimental motorglider, was making his second flight after having completed a number of high-speed taxi tests. The pilot said that several months earlier, on his first flight in the motorglider, shortly after becoming airborne the engine experienced a partial loss of power and he landed immediately. On the accident flight, immediately after takeoff, the pusher-configuration engine again lost power from 6,500 rpm to approximately 4,300 rpm. The pilot was not able to climb and was able to maintain flight at only 100 feet above ground level. Approximately one mile from the airport the pilot attempted an off-field emergency landing and then “did an intentional ground loop” to avoid a fence he had not noticed before touchdown. With the motorglider then moving sideways, the tail impacted a small tree. The carbon-fiber tail boom fractured and separated just forward of the vertical fin, causing substantial damage to the motorglider. The solo pilot was not injured. The pilot reported that there was adequate fuel in the tank and previous testing showed there was adequate fuel flow to the engine. After the accident the pilot reported that that his design of the engine cowling needed to be modified and he thought that “an engine compartment pressure differential from outside air caused the carburetor float bowl to empty.”
Factual narrative
The pilot, who is also the designer and builder of the experimental motorglider, was making his second flight after having completed a number of high-speed taxi tests. The pilot said that several months earlier, on his first flight in the motorglider, shortly after becoming airborne the engine experienced a partial loss of power and he landed immediately. On the accident flight, immediately after takeoff, the pusher-configuration engine again lost power from 6,500 rpm to approximately 4,300 rpm. The pilot was not able to climb and was able to maintain flight at only 100 feet above ground level. Approximately one mile from the airport the pilot attempted an off-field emergency landing and then “did an intentional ground loop” to avoid a fence he had not noticed before touchdown. With the motorglider then moving sideways, the tail impacted a small tree. The carbon-fiber tail boom fractured and separated just forward of the vertical fin, causing substantial damage to the motorglider. The solo pilot was not injured. The pilot reported that there was adequate fuel in the tank and previous testing showed there was adequate fuel flow to the engine. After the accident the pilot reported that that his design of the engine cowling needed to be modified and he thought that “an engine compartment pressure differential from outside air caused the carburetor float bowl to empty.”
Aircraft
- Registration
- N301TW
- Reported as
- Wells Terry Hula Girl
- Category
- Glider, amateur-built
- Serial number
- 001
- Airframe hours
- 1
- Engine
- Rotax 447 ULS, 40 horsepower, reciprocating
- Damage
- Substantial damage
- Flight
- Personal · Part 91
- Airworthiness certificate
- Special, Experimental (Special)
- Last inspection
- Condition · February 27, 2010 · 1 hours before
- Departed
- 4CO2 · Wellington, CO
- Destination
- 4CO2 · Wellington, CO
- Airport
- 4CO2 · Owl Canyon Gliderport, runway 19R, 3,580 × 24 ft, grass/turf
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 63
- Injuries
- None
- Certificate
- Private
- Airplane ratings
- Single-engine land
- Last flight review
- June 27, 2010
- Seat
- Single
- Flight hours
- 247 total · 1 in this make and model · 200 as pilot in command
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 130° at 11 knots, gusting 15
- Visibility
- 10 statute miles
- Temperature
- 91 °F, dew point 52 °F
- Altimeter
- 29.77 inHg
- Observed at
- FNL, 21 nm away
Docket · 1
The files NTSB released with the investigation on July 27, 2010, on NTSB’s docket system: statements, records, photos and specialists’ reports. 446 KB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.