# NTSB CEN10CA376: Wells Terry Hula Girl, N301TW, Wellington, CO, July 3, 2010 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: July 3, 2010, 12:00 local (18:00 UTC) - Place: Wellington, CO - Coordinates: 40.802776, -104.984169 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.8028&lon=-104.9842&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report October 21, 2010 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Denver FSDO - NTSB case key (mKey): 76556 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN10CA376 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/76556/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=76556 - Page: https://openairdocs.org/ntsb/CEN10CA376 ## Probable cause A partial loss of engine power due to the inadequate design of the engine cowling. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating)](https://openairdocs.org/ntsb-findings/01058500): Aircraft › Aircraft power plant · Design (probable cause); cases with it: [Wells Terry HULA GIRL, 1 case](https://openairdocs.org/ntsb-findings/01058500/cases.md?model=05614RT), [All aircraft, 497 cases](https://openairdocs.org/ntsb-findings/01058500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Miscellaneous/other](https://openairdocs.org/ntsb-events/900); cases with it: [Wells Terry HULA GIRL, 1 case](https://openairdocs.org/ntsb-events/900/sequence.md?model=05614RT), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) - [Takeoff: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Wells Terry HULA GIRL, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=05614RT), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Wells Terry HULA GIRL, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=05614RT), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Landing-landing roll: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Wells Terry HULA GIRL, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=05614RT), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Post-impact: Aircraft structural failure](https://openairdocs.org/ntsb-events/337); cases with it: [Wells Terry HULA GIRL, 1 case](https://openairdocs.org/ntsb-events/337/sequence.md?model=05614RT), [All aircraft, 290 cases](https://openairdocs.org/ntsb-events/337/sequence.md) ## 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](https://openairdocs.org/aircraft/N301TW), registered now, S/N 001, built 2003 (OpenAirDocs) - Reported make and model: WELLS TERRY HULA GIRL - Registry model: [Wells Terry HULA GIRL](https://openairdocs.org/model/wells-terry-hula-girl) (registry code 05614RT) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Glider, amateur-built - Serial number: 001 - Airframe hours: 1 - Engines: 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 ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: none; 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 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20100703038609A](https://openairdocs.org/incident/20100703038609A), Jul 3, 2010: Wells Terry HULA GIRL, Wellington, CO, Substantial damage. On 7/3/2010, N301TW, an amatuer built (Hula Girl) powered glider impacted the ground shortly after take-off at Owl Canyon Airport in Wellington, Colorado. The… ## Docket (1 files) The files NTSB released with the investigation on July 27, 2010, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=76556. 446 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 446 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40333414&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.