# NTSB CHI08CA252: Hiller UH-12E, N945HA, Cokato, MN, August 15, 2008 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: August 15, 2008, 07:00 local (12:00 UTC) - Place: Cokato, MN - Coordinates: 45.074443, -94.187225 - Nearby events: https://openairdocs.org/map.md?lat=45.0744&lon=-94.1872&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report September 26, 2008 - Report: Approved by Office Director - Parties: Minneapolis, MN FSDO - NTSB case key (mKey): 68873 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI08CA252 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/68873/pdf - Page: https://openairdocs.org/ntsb/CHI08CA252 ## Probable cause The pilot did not visually identify and maintain clearance with the power lines, and the pilot's inability to maintain control of the helicopter once it contacted the power lines. Factors associated with the accident were the low altitude operations being conducted and the power lines. ## 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 · Not specified (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) - [Info processing/decision: identification/recognition](https://openairdocs.org/ntsb-findings/02041510): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Hiller UH-12E, 2 cases](https://openairdocs.org/ntsb-findings/02041510/cases.md?model=4360122), [All aircraft, 559 cases](https://openairdocs.org/ntsb-findings/02041510/cases.md) - [Performance/control parameters: altitude](https://openairdocs.org/ntsb-findings/01062012): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Hiller UH-12E, 2 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md?model=4360122), [All aircraft, 1,310 cases](https://openairdocs.org/ntsb-findings/01062012/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Hiller UH-12E, 7 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=4360122), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Hiller UH-12E, 4 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=4360122), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md) - [Maneuvering-low-alt flying: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Hiller UH-12E, 7 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=4360122), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Uncontrolled descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Hiller UH-12E, 14 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=4360122), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot reported he made three passes over the fields that he was going to spray. He stated he noticed a power line pole that had a transformer cover on it and what appeared to be a wire covering running up the pole. This led the pilot to believe that the power lines in the area were buried. The pilot then landed and loaded the chemicals. He stated that after taking off with the load, he flew one more pass to look for power lines and still did not see any. He stated that during the first swath run, the helicopter contacted power lines. The helicopter initially pitched nose up and to the right. The pilot stated he pushed the nose down and to the left, but the power lines wrapped around the control tubes and tail rotor. The helicopter then entered a descending spin. The pilot stated he pulled back to flatten the descent just prior to the helicopter contacting the ground. ## Factual narrative On August 15, 2008, at 0700 central daylight time, a Hiller UH-12E helicopter collided with the terrain after contacting unmarked power lines during an aerial application flight in Cokato, Minnesota. The pilot was not injured and the helicopter was substantially damaged. The flight was operating under Title 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed and no flight plan was filed. The local flight originated just prior to the accident. The pilot reported he made three passes over the fields that he was going to spray. He stated he noticed a power line pole that had a transformer cover on it and what appeared to be a wire covering running up the pole. This led the pilot to believe that the power lines in the area were buried. The pilot then landed and loaded the chemicals. He stated that after taking off with the load, he flew one more pass to look for power lines and still did not see any. He stated that during the first swath run, the helicopter contacted power lines. The helicopter initially pitched nose up and to the right. The pilot stated he pushed the nose down and to the left, but the power lines wrapped around the control tubes and tail rotor. The helicopter then entered a descending spin. The pilot stated he pulled back to flatten the descent just prior to the helicopter contacting the ground. ## Aircraft - Registration: [N945HA](https://openairdocs.org/aircraft/N945HA), registered now, S/N 2057, built 1964 (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: 2057 - Engines: Lycoming VO-540 reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Registered owner: Triple H Aviation Inc - Airworthiness certificate: Special, Restricted (Special) - Departed: Cokato, MN ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 36; commercial; medical: class 2, with waivers/limitations; flight hours: 804 total, 703 in this make and model, 620 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 30° at 2 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 64 °F ## 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 20080815850449A](https://openairdocs.org/incident/20080815850449A), Aug 15, 2008: Hiller UH12E, Jacksonville, FL, Destroyed. (-23) The helicopter, a Hiller UH-12E was conducting an aerial spraying application to a corn field. During the first pass over the corn field the helicopter… 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.