# NTSB ANC06LA025: Robinson R44, N7528Z, Ilimana, AK, March 12, 2006 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: March 12, 2006, 13:20 local (17:20 UTC) - Place: Ilimana, AK - Coordinates: 59.799999, -155.318893 - Nearby events: https://openairdocs.org/map.md?lat=59.8000&lon=-155.3189&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report October 31, 2006 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: Anchorage FSDO - NTSB case key (mKey): 63341 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC06LA025 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/63341/pdf - Page: https://openairdocs.org/ntsb/ANC06LA025 ## Probable cause The pilot's continued flight into adverse weather conditions, and his spatial disorientation and loss of control during a subsequent landing attempt. Factors associated with the accident are flat light and whiteout conditions, fog, and snow-covered terrain. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight encounter with weather, maneuvering - light condition - other (contributing factor) - weather condition - whiteout (contributing factor) - weather condition - fog (contributing factor) - flight into known adverse weather - continued, pilot in command (cause) - In flight collision with terrain/water, landing - flare/touchdown - terrain condition - snow covered (contributing factor) - spatial disorientation, pilot in command (cause) - aircraft control - not maintained, pilot in command (cause) - Roll over, landing - flare/touchdown ## Analysis The commercial helicopter pilot was flying one passenger on an on-demand, Title 14, CFR Part 135 air taxi flight to a remote site in an area surrounded by snow-covered, flat, featureless terrain. Low fog, reduced visibility, and flat light conditions reduced his ability to discern a horizon or terrain. He said that the visibility deteriorated to about 1 or 2 miles, and he was unable to discern any topographic features on the snow-covered terrain, and he elected to make a precautionary landing to wait for better visibility. After about 10 minutes, he decided to continue to his destination. Just after takeoff, flat light conditions again reduced his ability to recognize any topographical features on the snow-covered terrain. He reported that while he was attempting to establish a stable hover, and erroneously believing that the helicopter was not moving, the helicopter's right skid struck the snow-covered terrain. The helicopter rolled to the right, and the main rotor blades struck the ground. As the main rotor blades struck the ground, the helicopter rolled onto its right side. The helicopter sustained substantial damage to the fuselage, tail boom assembly, and the main and tail rotor drive systems. The pilot reported that there were no preaccident mechanical anomalies with the helicopter. ## Factual narrative On March 12, 2006, about 1320 Alaska standard time, a skid-equipped Robinson R44 helicopter, N7528Z, sustained substantial damage after colliding with snow-covered terrain while maneuvering to land, about 10 miles west of Iliamna, Alaska. The helicopter was being operated as a visual flight rules (VFR) on-demand charter flight by Pollux Aviation, Wasilla, Alaska, under Title 14, CFR Part 135, when the accident occurred. The certificated commercial pilot and the sole passenger were not injured. Instrument meteorological conditions prevailed at the accident site. Visual meteorological conditions prevailed at the time of departure, and company flight following procedures were in effect. The flight originated about 1305, from the Iliamna Airport, Iliamna, and was en route to a remote, off-airport site. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on March 12, the pilot said that after departing from the Iliamna Airport, he flew west, en route to a remote drill site. According to the pilot, low fog, reduced visibility, and flat light conditions reduced his ability to discern a horizon or terrain. He said that the visibility deteriorated to about 1 or 2 miles, and he was unable to discern any topographic features on the surface of the flat, featureless, snow-covered terrain, and he elected to make a precautionary landing to wait for better visibility. After remaining on the ground for about 10 minutes, he decided to fly towards his destination. He said that just after takeoff, as the helicopter moved forward, flat light conditions and blowing snow, contributed to his inability to recognize any topographical features. He reported that while he was attempting to establish a stable hover, and erroneously believing that the helicopter was not moving, the helicopter's right skid struck the snow-covered terrain. The helicopter subsequently rolled to the right, and the main rotor blades struck the ground. As the main rotor blades struck the ground, the helicopter continued to roll onto its right side. The helicopter sustained substantial damage to the fuselage, tail boom assembly, and the main and tail rotor drive systems. In a written statement included in the NTSB Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1) submitted by the operator, dated March 20, 2006, the pilot reported weather conditions at the time of the accident to be, in part: Wind, calm; visibility, 3 statute miles; ceiling and clouds, 100 feet scattered, 200 feet overcast; temperature, 23 degrees F. ## Aircraft - Registration: [N7528Z](https://openairdocs.org/aircraft/N7528Z), registered now, S/N 10384, built 2004 (OpenAirDocs) - Reported make and model: Robinson R44 - 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: 10384 - Airframe hours: 1360 - Engines: Lycoming IO-540 205 horsepower reciprocating - Damage: Substantial damage - Flight: Part 135 - Registered owner: Pollux Aviation LTD - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, February 1, 2006 - Departed: ILI, ILIAMNA, AK - Destination: ILI, Ilimana, AK - Flight plan: Company VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 47; injuries: none; flight instructor, commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: right; flight hours: 4,600 total, 1,800 in this make and model, 4,530 as pilot in command, 60 in the last 90 days, 50 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Instrument (IMC), Day - Wind: calm - Visibility: 3 statute miles - Lowest ceiling: 200 ft overcast - Temperature: 23 °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 20060312003399A](https://openairdocs.org/incident/20060312003399A), Mar 12, 2006: Robsin R44RAVENII, Illiamna, AK, Substantial damage. (-23) Pilot, with one passenger on board, was operating his R44 helicopter on a CFR 135 passenger-carrying flight approximately 17 miles west of Illiamna,… 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.