# NTSB WPR11LA356: Sikorsky S-55B, N855TC, Brewster, WA, July 25, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: July 25, 2011, 11:45 local (18:45 UTC) - Place: Brewster, WA - Coordinates: 48.11861, -119.770835 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=48.1186&lon=-119.7708&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-hover: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report April 20, 2012 - Report: Approved by Office Director - NTSB office: Western Pacific Region - Parties: FAA FSDO - NTSB case key (mKey): 81354 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR11LA356 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/81354/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=81354 - Page: https://openairdocs.org/ntsb/WPR11LA356 ## Probable cause The pilot did not maintain main rotor rpm while hovering in gusting wind conditions. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Wind](https://openairdocs.org/ntsb-findings/03034000): Environmental issues › Conditions/weather/phenomena · Contributed to outcome; cases with it: [Sikorsky S55B, 1 case](https://openairdocs.org/ntsb-findings/03034000/cases.md?model=8141603), [All aircraft, 110 cases](https://openairdocs.org/ntsb-findings/03034000/cases.md) - [Performance/control parameters: prop/rotor parameters](https://openairdocs.org/ntsb-findings/01062052): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Sikorsky S55B, 1 case](https://openairdocs.org/ntsb-findings/01062052/cases.md?model=8141603), [All aircraft, 182 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md) - [Use of equip/info: use of equip/system](https://openairdocs.org/ntsb-findings/02063015): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Sikorsky S55B, 1 case](https://openairdocs.org/ntsb-findings/02063015/cases.md?model=8141603), [All aircraft, 1,391 cases](https://openairdocs.org/ntsb-findings/02063015/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-hover: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Sikorsky S55B, 1 case](https://openairdocs.org/ntsb-events/240/sequence.md?model=8141603), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Maneuvering-low-alt flying: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Sikorsky S55B, 2 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=8141603), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The helicopter pilot was conducting a low-level flight over orchards for the purpose of drying cherry trees. The orchard was bordered by a series of power lines, and a gusting, variable wind was present at the time of the flight. During a low hovering pass over the orchard, a gust of wind pushed the helicopter toward power lines. In an attempt to avoid the power lines, the pilot increased collective pitch, and the helicopter began to climb. During the climb, the main rotor rpm decayed and the nose of the helicopter yawed to the right. The pilot lowered the collective and increased the engine power in an effort to regain main rotor rpm; however, the helicopter descended into the orchard. The pilot reported no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operations, and that the accident could have been prevented if the flight had been conducted after the wind diminished. ## Factual narrative On July 25, 2011, about 1145 Pacific daylight time, a Sikorsky S-55B helicopter, N855TC, sustained substantial damage after impacting terrain near Brewster, Washington. The private pilot and pilot rated passenger were not injured. The helicopter sustained substantial damage to the fuselage, tail boom and main rotor drive system. The helicopter was registered to Golden Wings Aviation and operated under the provisions of Title 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the flight. The local flight originated from Brewster about 45 minutes prior to the accident. The private pilot reported that he was conducting a low level flight, for hire, over cherry orchards for the purpose of drying cherry trees. He reported that the orchard was bordered by a series of power lines and that gusty variable winds, with peak gusts to 30 knots, were present at the time of the flight. The pilot reported that during a low hovering pass over the orchard, a gust of wind from the left pushed the helicopter to the right, and towards the power lines. In an attempt to avoid the power lines, the pilot increased collective pitch and the helicopter began to climb. During the climb, the main rotor rpm decayed, and the nose of the helicopter yawed to the right. The pilot lowered the collective and increased the engine power in an effort to regain main rotor rpm; however, the helicopter descended into the orchard. The pilot reported no preimpact mechanical malfunctions or failures with the helicopter that would have precluded normal operations. The pilot further reported that the accident could have been prevented if the flight had been conducted after the wind diminished. ## Aircraft - Registration: [N855TC](https://openairdocs.org/aircraft/N855TC), registered now, S/N 551005, built 1956 (OpenAirDocs) - Reported make and model: SIKORSKY S-55B - Registry model: [Sikorsky S55B](https://openairdocs.org/model/sikorsky-s55b) (registry code 8141603) (OpenAirDocs) - Registry engine: [Wright R-1300-3D](https://openairdocs.org/engine/wright-r-1300-3d) (registry code 67134, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 551005 - Airframe hours: 7314 - Engines: Curtis - Wright R1300 690 horsepower reciprocating - Damage: Substantial damage - Flight: Other work use, Part 91 - Operator: Golden Wings - Registered owner: Smith David C - Airworthiness certificate: Standard, Normal - Last inspection: Annual, May 23, 2011 - Departed: Brewster, WA - Destination: Brewster, WA ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 42; injuries: none; private; medical: class 2, without waivers/limitations; last flight review June 1, 2010; seat: right; flight hours: 318 total, 109 in this make and model, 192 as pilot in command, 25 in the last 90 days, 22 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 10 knots, gusting 30 - Visibility: 10 statute miles - Lowest ceiling: 4,000 ft broken - Temperature: 70 °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 20110725015669A](https://openairdocs.org/incident/20110725015669A), Jul 25, 2011: Sikorsky S55B, Brewster, WA, Minor damage. Individual was conducting cherry drying (hover oge) when wind gust pushed him towards a power line. Pilot pulled pitch to clear line. RPM bled off. After… ## Docket (3 files) The files NTSB released with the investigation on March 15, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=81354. 448 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 362 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353314&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Record of Conversation - Smith (item 2, .PDF, 43 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353381&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Smith-Redacted.PDF - Record of Conversation - Snow (item 3, .PDF, 43 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40353382&FileExtension=.PDF&FileName=Record%20of%20Conversation%20-%20Snow-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.