# NTSB ERA11CA355: Dotson William P Sngl Seat Hawk Arrow, N4209F, Carthage, NC, June 20, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: June 20, 2011, 10:00 local (14:00 UTC) - Place: Carthage, NC - Coordinates: 35.338333, -79.435554 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.3383&lon=-79.4356&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern base: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report December 27, 2011 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/ FSDO - NTSB case key (mKey): 80863 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA11CA355 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/80863/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=80863 - Page: https://openairdocs.org/ntsb/ERA11CA355 ## Probable cause A partial loss of engine power due to the pilot’s improper installation of the engine’s No. 1 cylinder spark plugs. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: repair](https://openairdocs.org/ntsb-findings/02062015): Personnel issues › Task performance · Owner/builder (probable cause); cases with it: [Dotson William P SNGL SEAT HAWK ARROW, 1 case](https://openairdocs.org/ntsb-findings/02062015/cases.md?model=0590006), [All aircraft, 99 cases](https://openairdocs.org/ntsb-findings/02062015/cases.md) - [Ignition system: spark plugs/igniters](https://openairdocs.org/ntsb-findings/01057421): Aircraft › Aircraft power plant · Failure (probable cause); cases with it: [Dotson William P SNGL SEAT HAWK ARROW, 1 case](https://openairdocs.org/ntsb-findings/01057421/cases.md?model=0590006), [All aircraft, 38 cases](https://openairdocs.org/ntsb-findings/01057421/cases.md) - [Ignition system: spark plugs/igniters](https://openairdocs.org/ntsb-findings/01057421): Aircraft › Aircraft power plant · Incorrect service/maintenance (probable cause); cases with it: [Dotson William P SNGL SEAT HAWK ARROW, 1 case](https://openairdocs.org/ntsb-findings/01057421/cases.md?model=0590006), [All aircraft, 38 cases](https://openairdocs.org/ntsb-findings/01057421/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: Aircraft maintenance event](https://openairdocs.org/ntsb-events/040); cases with it: [Dotson William P SNGL SEAT HAWK ARROW, 1 case](https://openairdocs.org/ntsb-events/040/sequence.md?model=0590006), [All aircraft, 484 cases](https://openairdocs.org/ntsb-events/040/sequence.md) - [Approach-VFR pattern base: Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342) (defining event); cases with it: [Dotson William P SNGL SEAT HAWK ARROW, 1 case](https://openairdocs.org/ntsb-events/342/sequence.md?model=0590006), [All aircraft, 1,858 cases](https://openairdocs.org/ntsb-events/342/sequence.md) - [Approach-VFR pattern final: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Dotson William P SNGL SEAT HAWK ARROW, 1 case](https://openairdocs.org/ntsb-events/470/sequence.md?model=0590006), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis According to the pilot, during the turn from the base leg to final approach, the engine experienced a partial loss of power. He performed a forced landing into some small trees because he knew he could not glide the airplane to the runway. The airplane sustained substantial damage to the wing spars. A postaccident examination revealed that a spark plug was backed out of the No. 1 cylinder and was suspended from the electrode wire. The pilot reported that he had changed the engine spark plugs the day before the accident and that he may have cross-threaded one of them. ## Factual narrative According to the pilot during the turn from the base leg to the final approach the engine experienced a partial loss of power. The airplane impacted a tree causing substantial damage to the wing spars. A Federal Aviation Administration inspector examined the wreckage and noted that one spark plug was found backed out of the No. 1 cylinder and was suspended from the electrode wire. The pilot reported that he had changed the engine spark plugs the day before the accident and that he may have cross-threaded one of the spark plugs. ## Aircraft - Registration: [N4209F](https://openairdocs.org/aircraft/N4209F), registered now, S/N H-SSA-899-R503-TRI, built 2004 (OpenAirDocs) - Reported make and model: DOTSON WILLIAM P SNGL SEAT HAWK ARROW - Registry model: [Dotson William P SNGL SEAT HAWK ARROW](https://openairdocs.org/model/dotson-william-p-sngl-seat-hawk-arrow) (registry code 0590006) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Airplane, amateur-built - Serial number: H-SSA-899-R503-TRI - Airframe hours: 195 - Engines: Rotax 503 50 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Special, Experimental (Special) - Last inspection: Annual, February 13, 2011, 25 hours before - Departed: 5NC3, Carthage, NC - Destination: 5NC3, Carthage, NC - Airport: 5NC3, Gilliam McConnell, runway 31, 2,500 × 36 ft, asphalt ## Flight crew As NTSB recorded them. NTSB leaves out names. - Student pilot; age 53; injuries: none; student; airplane ratings: single-engine land; medical: sport pilot; seat: single; flight hours: 38 total, 5 in this make and model, 7 as pilot in command, 15 in the last 90 days, 10 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 310° at 6 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 82 °F, dew point 68 °F - Altimeter: 29.87 inHg - Observed at: KSOP, 8 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 20110620025049A](https://openairdocs.org/incident/20110620025049A), Jun 20, 2011: Dotson William P SNGL SEAT HAWK ARROW, Carthage, NC, Substantial damage. On June 20, 2011, approximately 1030 EDT, a cgs hawk arrow registered to [privacy data omitted] was piloted by [privacy data omitted]. The aircraft was in… ## Docket (5 files) The files NTSB released with the investigation on November 7, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=80863. 6.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40350525&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Pilot Interview Summary (item 2, .PDF, 30 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40350475&FileExtension=.PDF&FileName=Pilot%20Interview%20Summary-Master.PDF - Carthage NC (SOP) Meteorological Conditions (item 3, .PDF, 62 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40350613&FileExtension=.PDF&FileName=Carthage%20NC%20(SOP)%20Meteorological%20Conditions-Master.PDF - Photo 1 - View of spark plugs (Courtesy of FAA) (item 4, .PDF, 375 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40350478&FileExtension=.PDF&FileName=Photo%201%20-%20View%20of%20spark%20plugs%20(Courtesy%20of%20FAA)-Master.PDF - Photo 2 - Wreckage Overview (Courtesy of FAA) (item 5, .PDF, 3.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40350671&FileExtension=.PDF&FileName=Photo%202%20-%20Wreckage%20Overview%20(Courtesy%20of%20FAA)-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.