# NTSB WPR09CA339: Robinson Helicopter R44, N244HP, Marysville, CA, July 13, 2009

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Data collection · Final report
- Date: July 13, 2009, 10:15 local (17:15 UTC)
- Place: Marysville, CA
- Coordinates: 39.228054, -121.308052 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=39.2281&lon=-121.3081&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: 3 uninjured
- Status: Completed, report September 30, 2009
- Report: Approved by Office Director
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Administration FSDO
- NTSB case key (mKey): 74265
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR09CA339
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/74265/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=74265
- Page: https://openairdocs.org/ntsb/WPR09CA339

## Probable cause

The pilot’s failure to maintain adequate clearance from the power line wires.

## 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 · Response/compensation (probable cause); cases with it: [Robinson Helicopter R44, 18 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md?model=7640120), [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: [Robinson Helicopter R44, 21 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=7640120), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/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: [Robinson Helicopter R44, 26 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=7640120), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md)
- [Autorotation: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Robinson Helicopter R44, 13 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7640120), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing-flare/touchdown: Roll over](https://openairdocs.org/ntsb-events/097); cases with it: [Robinson Helicopter R44, 17 cases](https://openairdocs.org/ntsb-events/097/sequence.md?model=7640120), [All aircraft, 261 cases](https://openairdocs.org/ntsb-events/097/sequence.md)

## Analysis

The private pilot reported that he was flying the helicopter about 500 feet above the ground and decided to descend to follow a riverbed. While descending to the river, one of the passengers alerted him to the presence of power line wires that obstructed their flight path. The pilot applied full aft cyclic and collective in an attempt to avoid colliding with the wires; however, the tail boom and tail rotor contacted the wires. The impact resulted in the separation of the tail rotor blades and the bottom section of the vertical stabilizer from the helicopter. Following the collision the pilot initiated an autorotation. Upon touchdown, the helicopter bounced and when it touched down again, it was moving sideways to the left and rolled over. The helicopter came to rest on the bank of the river on its left side. Examination of the helicopter revealed substantial damage to the main rotor assembly, the tail rotor assembly, vertical stabilizer, tail boom, and fuselage. The pilot reported that there were no mechanical anomalies with the helicopter prior to the accident.

## Factual narrative

The private pilot reported that he was flying the helicopter about 500 feet above the ground and decided to descend to follow a riverbed. While descending to the river, one of the passengers alerted him to the presence of power line wires that obstructed their flight path. The pilot applied full aft cyclic and collective in an attempt to avoid colliding with the wires; however, the tail boom and tail rotor contacted the wires. The impact resulted in the separation of the tail rotor blades and the bottom section of the vertical stabilizer from the helicopter. Following the collision the pilot initiated an autorotation. Upon touchdown, the helicopter bounced and when it touched down again, it was moving sideways to the left and rolled over. The helicopter came to rest on the bank of the river on its left side. Examination of the helicopter revealed substantial damage to the main rotor assembly, the tail rotor assembly, vertical stabilizer, tail boom, and fuselage. The pilot reported that there were no mechanical anomalies with the helicopter prior to the accident.

## Aircraft

- Registration: [N244HP](https://openairdocs.org/deregistered/N244HP-2012-05-17), registration cancelled 2012-05-17, S/N 0427, built 1998 (OpenAirDocs)
- Reported make and model: ROBINSON HELICOPTER R44
- Registry model: [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44) (registry code 7640120) (OpenAirDocs)
- Registry engine: [Lycoming O-540-F1B5](https://openairdocs.org/engine/lycoming-o-540-f1b5) (registry code 42353, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 0427
- Airframe hours: 1106
- Engines: LYCOMING O-540-F1B5 260 horsepower reciprocating
- Damage: Substantial damage
- Flight: Personal, Part 91
- Operator: Dwelle David W
- Registered owner: Dwelle David W
- Airworthiness certificate: Standard, Normal
- Departed: AUN, Auburn, CA
- Destination: KAUN, Auburn, CA

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 61; injuries: none; private; airplane ratings: single-engine land; medical: class 3, with waivers/limitations; last flight review March 15, 2009; seat: right; flight hours: 1,250 total, 105 in this make and model, 30 in the last 90 days, 8 in the last 30 days, 0 in the last 24 hours

## Weather

- Conditions: Visual (VMC), Day
- Wind: 330° at 12 knots
- Visibility: 10 statute miles
- Lowest ceiling: none
- Temperature: 79 °F, dew point 45 °F
- Altimeter: 30.01 inHg
- Observed at: MYV, 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 20090713013479A](https://openairdocs.org/incident/20090713013479A), Jul 13, 2009: Robsin R44, Marysville, CA, Substantial damage. (-23) Pilot departed auburn airport at approximately 10 am enroute to nelson, CA. While enroute at 500 AGL, the pilot and his passengers decided to fly at a…

## Docket (1 files)

The files NTSB released with the investigation on July 24, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=74265. 1.1 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40316436&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.