# NTSB CEN09CA359: Hiller UH-12E, N34SD, Stringtown, OK, June 11, 2009 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: June 11, 2009, 07:40 local (12:40 UTC) - Place: Stringtown, OK - Coordinates: 34.417499, -96.050552 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.4175&lon=-96.0506&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 10, 2009 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Flight Standards District Office - NTSB case key (mKey): 74056 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN09CA359 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74056/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74056 - Page: https://openairdocs.org/ntsb/CEN09CA359 ## Probable cause The pilot's failure to maintain clearance from power lines. Contributing to the accident was the pilot's preoccupation with personal affairs. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Object/animal/substance: wire](https://openairdocs.org/ntsb-findings/03022032): Environmental issues › Physical environment · Awareness of condition (probable cause); cases with it: [Hiller UH-12E, 4 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md?model=4360122), [All aircraft, 588 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md) - [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Hiller UH-12E, 4 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=4360122), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md) - [Mental/emotional state](https://openairdocs.org/ntsb-findings/02022500): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Hiller UH-12E, 1 case](https://openairdocs.org/ntsb-findings/02022500/cases.md?model=4360122), [All aircraft, 21 cases](https://openairdocs.org/ntsb-findings/02022500/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Collision during takeoff/land](https://openairdocs.org/ntsb-events/490) (defining event); cases with it: [Hiller UH-12E, 1 case](https://openairdocs.org/ntsb-events/490/sequence.md?model=4360122), [All aircraft, 1,309 cases](https://openairdocs.org/ntsb-events/490/sequence.md) ## Analysis The company's president reported that the helicopter pilot was "taking off from an area with large bushes and scrubby trees about 500 feet ahead. He believed he was somewhat distracted because of learning of the serious illness of his mother. ...When it appeared he might have difficulty clearing the obstacles to the left, he turned right to pass under the power lines. The tail rotor snagged the lower power line, causing the helicopter to impact the ground... The wreckage remained intact except for portions of the tail rotor and main rotor which broke off after impact." An unidentified witness reported that the helicopter had struck "lines" while conducting agricultural operations, and that the helicopter was "shattered" and "totaled." The caller stated that the helicopter wreckage had been recovered and relocated to Mineral Wells, Texas. ## Factual narrative The company's president reported that the pilot was "taking off from an area with large bushes and scrubby trees about 500 feet ahead. He believed he was somewhat distracted because of learning of the serious illness of his mother. ...When it appeared he might have difficulty clearing the obstacles to the left, he turned right to pass under the power lines. The tail rotor snagged the lower power line, causing the helicopter to impact the ground... The wreckage remained intact except for portions of the tail rotor and main rotor which broke off after impact." An unidentified witness reported that the helicopter had struck "lines" while conducting agricultural operations, and that the helicopter was "shattered" and "totaled." The caller stated that the helicopter wreckage had been recovered and relocated to Mineral Wells, Texas. ## Aircraft - Registration: [N34SD](https://openairdocs.org/aircraft/N34SD), registered now, S/N 1618, built 1965 (OpenAirDocs) - Reported make and model: HILLER UH-12E - Registry model: [Hiller UH-12E](https://openairdocs.org/model/hiller-uh-12e) (registry code 4360122) (OpenAirDocs) - Registry engine: [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series) (registry code 41534, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 1618 - Airframe hours: 4139 - Engines: LYCOMING VO-540-B1A 305 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Texas Air Cargo, Inc. - Registered owner: Texas Air Cargo, Inc. - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, August 26, 2008, 55 hours before - Departed: NONE, Stringtown, OK - Destination: NONE, Stringtown, OK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 61; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; medical: class 2, with waivers/limitations; last flight review March 12, 2009; seat: center; flight hours: 23,219 total, 825 in this make and model, 23,119 as pilot in command, 55 in the last 90 days, 52 in the last 30 days ## Weather - Conditions: Instrument (IMC), Day - Wind: calm - Visibility: 10 statute miles - Lowest ceiling: 300 ft - Temperature: 77 °F, dew point 72 °F - Altimeter: 30.09 inHg - Observed at: AQR, 7 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 20090611010329A](https://openairdocs.org/incident/20090611010329A), Jun 11, 2009: Hiller UH12E, Stringtown, OK, Substantial damage. A mechanic at the repair facility the wreckage was taken to, advises he was told, that on the first load of the day the helicopter hopper tanks were loaded… ## Other investigations on N34SD (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 DFW08LA100](https://openairdocs.org/ntsb/DFW08LA100), Apr 7, 2008: Hiller UH-12E (N34SD), Quinton, OK, substantial damage. Probable cause: An undetermined mechanical malfuction associated with the tail rotor drive system which led to a loss of control. ## Docket (3 files) The files NTSB released with the investigation on July 17, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74056. 891 KB in all. - NTSB Form 6120.1-2, Pilot-Operator Aircraft Accident Report (item 1, .PDF, 505 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40316044&FileExtension=.PDF&FileName=NTSB%20Form%206120.1-2,%20Pilot-Operator%20Aircraft%20Accident%20Report-Redacted.PDF - Map of Accident Area (item 2, .PDF, 332 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40316045&FileExtension=.PDF&FileName=Map%20of%20Accident%20Area-Master.PDF - Weather Reports and Records (item 3, .PDF, 55 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40316046&FileExtension=.PDF&FileName=Weather%20Reports%20and%20Records-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.