Pilot Debrief

WELLS TERRY HULA GIRL near Wellington, CO — 2010-07-03

Final reportCEN10CA376
Sign in to save
Date
2010-07-03
Location
Wellington, CO, USA
Airport
4CO2
Aircraft
WELLS TERRY HULA GIRL
Registration
N301TW
Category
Glider
Highest injury
None
Fatalities
0
Phase of flight
Takeoff roll

Probable cause

A partial loss of engine power due to the inadequate design of the engine cowling.

NTSB 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.”

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Pilot could have aborted takeoff after initial power loss.

NTSB coding

Evidence available

  • 1 docket document
View NTSB final reportView NTSB docket

Docket documents1

Related mishaps