# NTSB ANC14CA042: Robinson Helicopter R44 II, N74713, Coldfoot, AK, June 18, 2014 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: June 18, 2014, 09:45 local (17:45 UTC) - Place: Coldfoot, AK - Coordinates: 67.769447, -149.748336 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=67.7694&lon=-149.7483&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-hover: Settling with power/vortex ring state](https://openairdocs.org/ntsb-events/244) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report August 14, 2014 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA Fairbanks FSDO - NTSB case key (mKey): 89480 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC14CA042 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/89480/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=89480 - Page: https://openairdocs.org/ntsb/ANC14CA042 ## Probable cause The pilot's failure to maintain adequate main rotor rpm while maneuvering at a low altitude, which resulted in an emergency landing on uneven terrain. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Robinson Helicopter R44 II, 99 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=7640122), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/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: [Robinson Helicopter R44 II, 17 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md?model=7640122), [All aircraft, 182 cases](https://openairdocs.org/ntsb-findings/01062052/cases.md) - [Terrain: sloped/uneven terrain](https://openairdocs.org/ntsb-findings/03021017): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Robinson Helicopter R44 II, 10 cases](https://openairdocs.org/ntsb-findings/03021017/cases.md?model=7640122), [All aircraft, 270 cases](https://openairdocs.org/ntsb-findings/03021017/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-hover: Settling with power/vortex ring state](https://openairdocs.org/ntsb-events/244) (defining event); cases with it: [Robinson Helicopter R44 II, 6 cases](https://openairdocs.org/ntsb-events/244/sequence.md?model=7640122), [All aircraft, 52 cases](https://openairdocs.org/ntsb-events/244/sequence.md) - [Emergency descent: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Robinson Helicopter R44 II, 95 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7640122), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The commercial helicopter pilot reported that the purpose of the flight was to transport two technicians to a remote site in an area of mountainous terrain. The pilot fueled the helicopter and flew approximately 30 minutes to a staging area. After loading the two passengers and their gear, he flew to the planned landing zone (LZ), in a narrow box-valley at about 2,550 feet MSL. The proposed LZ was evaluated while performing an out-of-ground-effect hover, but the pilot determined the LZ was unsuitable. A second LZ was evaluated using the same process and also found unsuitable. While hovering out of ground effect, above a third potential LZ, the helicopter began to descend and the pilot added collective pitch to stop the descent. He said the low rotor annunciator horn then sounded and the helicopter continued to descend. In an attempt to avoid landing in an area of uneven terrain, the pilot said he opted to turn the helicopter to the right and downslope, while trying to override the engine governor to attain additional engine power. The helicopter's skids subsequently struck an area of uneven, down sloping terrain. During touchdown, the helicopter nosed down, pivoted to the left, and rolled onto its left side. The helicopter sustained substantial damage to the fuselage, tail boom and main rotor drive system. The pilot reported no preaccident mechanical anomalies with the helicopter that would have precluded normal operation. The pilot characterized the down sloping wind conditions as light and variable. ## Factual narrative The commercial helicopter pilot reported that the purpose of the flight was to transport two technicians to a remote site in an area of mountainous terrain. The pilot fueled the helicopter and flew approximately 30 minutes to a staging area. After loading the two passengers and their gear, he flew to the planned landing zone (LZ), in a narrow box-valley at about 2,550 feet MSL. The proposed LZ was evaluated while performing an out-of-ground-effect hover, but the pilot determined the LZ was unsuitable. A second LZ was evaluated using the same process and also found unsuitable. While hovering out of ground effect, above a third potential LZ, the helicopter began to descend and the pilot added collective pitch to stop the descent. He said the low rotor annunciator horn then sounded and the helicopter continued to descend. In an attempt to avoid landing in an area of uneven terrain, the pilot said he opted to turn the helicopter to the right and downslope, while trying to override the engine governor to attain additional engine power. The helicopter's skids subsequently struck an area of uneven, down sloping terrain. During touchdown, the helicopter nosed down, pivoted to the left, and rolled onto its left side. The helicopter sustained substantial damage to the fuselage, tail boom and main rotor drive system. The pilot reported no preaccident mechanical anomalies with the helicopter that would have precluded normal operation. The pilot characterized the down sloping wind conditions as light and variable. ## Aircraft - Registration: [N74713](https://openairdocs.org/deregistered/N74713-2018-12-18), registration cancelled 2018-12-18, S/N 11220, built 2006 (OpenAirDocs) - Reported make and model: ROBINSON HELICOPTER COMPANY R44 II (Raven II) - Registry model: [Robinson Helicopter R44 II](https://openairdocs.org/model/robinson-helicopter-r44-ii) (registry code 7640122) (OpenAirDocs) - Registry engine: [Lycoming IO-540 series](https://openairdocs.org/engine/lycoming-io-540-series) (registry code 41530, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 11220 - Year built: 2006 - Airframe hours: 3175 - Engines: LYCOMING IO-540 SER 245 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Operator: Quicksilver Air Inc - Registered owner: Quicksilver Air Inc - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 5, 2014 - Departed: CXF, COLDFOOT, AK - Destination: Coldfoot, AK - Flight plan: Company VFR - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 46; injuries: none; flight instructor, commercial; instrument ratings: helicopter; medical: class 2, with waivers/limitations; last flight review May 13, 2014; seat: right; restraint: 3-point; flight hours: 3,700 total, 2,700 in this make and model, 3,600 as pilot in command, 160 in the last 90 days, 110 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 30° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: 13,000 ft overcast - Temperature: 57 °F, dew point 52 °F - Altimeter: 29.43 inHg - Observed at: PABT, 83 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 20140618011719A](https://openairdocs.org/incident/20140618011719A), Jun 18, 2014: Robinson Helicopter Company R44 II, Coldfoot, AK, Substantial damage. An R-44 helicopter operating under PART135 in VFR conditions, picked up 2 passengers and attempted a landing approximately 35 NM north of Coldfoot AK. The… ## Docket (1 files) The files NTSB released with the investigation on August 6, 2014, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=89480. 852 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 852 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40414663&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-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.