# NTSB CEN13LA055: Central Ohio Dragonfly Club DRAGONFLY-C, N667DF, Darbyville, OH, November 4, 2012 - Type: NTSB accident investigation - Classification: Accident · Serious injuries · Limited investigation · Final report - Date: November 4, 2012, 12:30 local (17:30 UTC) - Place: Darbyville, OH - Coordinates: 39.702499, -83.147224 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.7025&lon=-83.1472&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Serious injuries - Injuries: 1 serious - Status: Completed, report September 30, 2014 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration, Columbus FSDO - NTSB case key (mKey): 85536 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN13LA055 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/85536/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=85536 - Page: https://openairdocs.org/ntsb/CEN13LA055 ## Probable cause The total loss of engine power due to a cold-seizure event that occurred at a low altitude, which precluded the pilot's recovery from an inadvertent aerodynamic stall/spin. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Engine (reciprocating): recip eng cyl section](https://openairdocs.org/ntsb-findings/01058530): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Central Ohio Dragonfly Clubllc DRAGONFLY-C, 1 case](https://openairdocs.org/ntsb-findings/01058530/cases.md?model=05901ZQ), [All aircraft, 373 cases](https://openairdocs.org/ntsb-findings/01058530/cases.md) - [Performance/control parameters: airspeed](https://openairdocs.org/ntsb-findings/01062010): Aircraft › Aircraft oper/perf/capability · Attain/maintain not possible (probable cause); cases with it: [Central Ohio Dragonfly Clubllc DRAGONFLY-C, 1 case](https://openairdocs.org/ntsb-findings/01062010/cases.md?model=05901ZQ), [All aircraft, 1,681 cases](https://openairdocs.org/ntsb-findings/01062010/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Central Ohio Dragonfly Clubllc DRAGONFLY-C, 1 case](https://openairdocs.org/ntsb-events/341/sequence.md?model=05901ZQ), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Initial climb: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Central Ohio Dragonfly Clubllc DRAGONFLY-C, 1 case](https://openairdocs.org/ntsb-events/241/sequence.md?model=05901ZQ), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Central Ohio Dragonfly Clubllc DRAGONFLY-C, 2 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=05901ZQ), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The accident occurred during an aero-tow of a hang glider. The pilot reported that during initial climb, about 80 feet above the runway, the airplane experienced a sudden and total loss of engine power while it was in a climbing left turn. He stated that the airplane immediately entered an aerodynamic stall/spin following the loss of engine power. The pilot released the towed hang glider, but he was unable recover from the aerodynamic stall condition before the airplane impacted terrain. A postaccident examination of the two-cylinder engine revealed excessive piston scoring within one of the cylinder assemblies and excessive wear on the piston wrist-pin. The observed anomalies were consistent with a cold-seizure event. A cold-seizure event is a thermo-imbalance condition between the piston and cylinder, which results in an insufficient clearance between the piston and the cylinder. The cylinder thermo-imbalance condition is typically the result of an insufficient engine warm-up period before takeoff power is applied. However, the conditions that led to the cold-seizure event may not have been limited to the accident flight. The total loss of engine power during initial climb, while towing a hang glider, likely contributed to the aerodynamic stall/spin encountered at a low altitude. Additionally, the low altitude at which the aerodynamic stall/spin was encountered was likely insufficient to have allowed a recovery before the airplane impacted terrain. ## Factual narrative On November 4, 2012, about 1230 eastern standard time, an experimental Dragonfly-C airplane, N667DF, was substantially damaged when it collided with terrain following a loss of engine power during initial climb from WesMar Aerodrome, a private airstrip located near Darbyville, Ohio. The private pilot was seriously injured. The airplane was registered to and operated by Central Ohio Dragonfly Club, LLC, under the provisions of 14 Code of Federal Regulations Part 91 without a flight plan. Day visual meteorological conditions prevailed for the local area hang glider aero-tow flight that was originating at the time of the accident. The pilot reported that during initial climb from runway 5 (2,300 feet by 60 feet, grass/turf), about 80 feet above the runway, the airplane experienced a sudden and total loss of engine power while it was in a climbing left turn. He stated that the airplane immediately entered an aerodynamic stall/spin following the loss of engine power. The pilot released the towed hang glider, but he was unable recover from the aerodynamic stall condition before the airplane impacted terrain. The airplane sustained substantial damage to the fuselage and both wings. The pilot reportedly sustained a broken left ankle.A postaccident examination of the two-cylinder Rotax model 582 engine, completed by a Federal Aviation Administration Inspector, revealed excessive piston scoring within one of the cylinder assemblies. Additionally, there was excessive wear observed on the piston wrist-pin. The observed anomalies were consistent with a cold-seizure event, as described in a service training publication provided by the engine manufacturer. The engine manufacturer described a cold-seizure event as a thermo-imbalance condition between the piston and cylinder, which results in insufficient clearance between the piston and the cylinder. Additionally, the engine manufacturer stated that the cylinder thermo-imbalance is typically the result of an insufficient engine warm-up period before takeoff power is applied. The engine, serial number 5742422, had accumulated 205 hours since new. ## Aircraft - Registration: [N667DF](https://openairdocs.org/aircraft/N667DF), registered now, S/N C-88, built 2006 (OpenAirDocs) - Reported make and model: CENTRAL OHIO DRAGONFLY CLUB DRAGONFLY-C - Registry model: [Central Ohio Dragonfly Clubllc DRAGONFLY-C](https://openairdocs.org/model/central-ohio-dragonfly-clubllc-dragonfly-c) (registry code 05901ZQ) (OpenAirDocs) - Registry engine: [Rotax 582SER](https://openairdocs.org/engine/rotax-582ser) (registry code 55556, 2 cycle) (OpenAirDocs) - Category: Airplane - Serial number: C-88 - Year built: 2006 - Airframe hours: 367 - Engines: ROTAX 582 65 horsepower reciprocating - Damage: Substantial damage - Flight: Glider tow, Part 91 - Operator: Central Ohio Dragonfly Club, LLC, doing business as Central Ohio Dragonfly Club, LLC - Registered owner: Central Ohio Dragonfly Club, LLC - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, May 16, 2012 - Departed: PVT, Darbyville, OH - Destination: PVT, Darbyville, OH - Airport: PVT, WesMar Aerodrome, runway 05, 2,300 × 60 ft, grass/turf - Equipment: Airframe parachute ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: serious; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review September 18, 2011; seat: front; flight hours: 368 total, 305 in this make and model, 305 as pilot in command, 26 in the last 90 days, 7 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 360° at 4 knots - Visibility: 10 statute miles - Lowest ceiling: 4,100 ft overcast - Temperature: 46 °F, dew point 27 °F - Altimeter: 30.13 inHg - Observed at: LCK, 12 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 20121104026779A](https://openairdocs.org/incident/20121104026779A), Nov 4, 2012: Central Ohio Dragonfly Clubllc DRAGONFLY-C, Darbyville, OH, Substantial damage. At the wesmar aerodrome in Darbyville Ohio N667DF was taking off on a grass strip while towing a hang glider. At mid field the pilot turned north into the… ## Other investigations on N667DF (1) 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. - [NTSB CEN10CA569](https://openairdocs.org/ntsb/CEN10CA569), Sep 26, 2010: Central Ohio Dragonfly Clubllc DRAGONFLY-C (N667DF), Orient, OH, substantial damage. Probable cause: The pilot's failure to disconnect the tow bridal line prior to takeoff. ## Docket (2 files) The files NTSB released with the investigation on August 28, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=85536. 2.4 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40396315&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - FAA Engine Teardown Report (item 2, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40396317&FileExtension=.PDF&FileName=FAA%20Engine%20Teardown%20Report-Master.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.