# NTSB ANC02TA035: Robinson R-44, N344AK, Cantwell, AK, May 16, 2002 - Type: NTSB accident investigation - Classification: Accident · No injuries · Final report - Date: May 16, 2002, 12:30 local (20:30 UTC) - Place: Cantwell, AK - Coordinates: 63.27, -149.765548 - Nearby events: https://openairdocs.org/map.md?lat=63.2700&lon=-149.7655&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report December 6, 2002 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: DEPARTMENT OF INTERIOR, O.A.S., FAA-AL-FAI FSDO 01 - NTSB case key (mKey): 54720 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC02TA035 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/54720/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=54720 - Page: https://openairdocs.org/ntsb/ANC02TA035 ## Probable cause A failure of the pilot-in-command to maintain adequate main rotor rpm during an out-of-ground-effect hover. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with object, hover - out of ground effect - rotor rpm - not maintained, pilot in command (cause) - object - tree(s) ## Analysis The commercial certificated helicopter pilot was conducting a VFR public use government flight to track caribou. The pilot was maneuvering a helicopter in an attempt to move radio-collared caribou out of an area of trees. Prior to beginning the maneuvering, the pilot said he conducted an out-of-ground-effect hover power check, and was satisfied with the helicopter's available power. He then began an out-of-ground-effect hover near several caribou. The pilot said that when he raised the collective control to move from his hover position, the low rotor annunciator sounded. He said he did not have sufficient power available to climb away from his position, and the helicopter began to settle toward the ground. One of the helicopter landing gear skids settled into low bushes, and the pilot was able to regain sufficient rotor RPM to move to a nearby landing area. After landing, the pilot found that one of the main rotor blades had a tear in the bottom surface of the blade surface. The other main rotor blade had several dents. The pilot determined the helicopter was not flyable. He said he did not feel any rotor contact with the trees. ## Factual narrative On May 16, 2002, about 1230 Alaska daylight time, a Robinson R-44 helicopter, N344AK, sustained substantial damage while maneuvering near trees, about 23 miles southwest of Cantwell, Alaska. The helicopter was being operated as a visual flight rules (VFR) public use government flight when the accident occurred. The helicopter is registered to Quicksilver Air Inc., Fairbanks, Alaska, and was operated under contract by the U.S. Geological Survey, Anchorage, Alaska. The commercial certificated pilot, and the two passengers, were not injured. Visual meteorological conditions prevailed. A VFR flight plan was filed. The flight originated at the McKinley National Park airport, Denali National Park, Alaska, about 1130. The U.S. Department of Interior, Office of Aircraft Services, Boise, Idaho, notified the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on May 16, that the helicopter was being utilized by the U.S. Geological Survey to track caribou. The area of the accident was in the Denali National Park boundary. During a telephone conversation with the NTSB IIC on May 16, the pilot reported that he was maneuvering the helicopter in an attempt to move radio-collared caribou out of an area of trees along the west fork of the Chulitna River. Prior to beginning the maneuvering, the pilot said he conducted an out-of-ground-effect hover power check, and was satisfied with the helicopter's available power. He then began an out-of-ground-effect hover near several caribou. The pilot said that when he raised the collective control to move from his hover position, the low rotor annunciator sounded. He said he did not have sufficient power available to climb away from his position, and the helicopter began to settle toward the ground. One of the helicopter landing gear skids settled into low bushes, and the pilot was able to regain sufficient rotor RPM to move to a nearby landing area. After landing, the pilot found that one of the main rotor blades had a tear in the bottom surface of the blade surface. The other main rotor blade had several dents. The pilot determined the helicopter was not flyable. He said he did not feel any rotor contact with the trees. The pilot described the weather conditions as clear, wind from the southeast about 10 knots, and the temperature was 52 degrees F. ## Aircraft - Registration: N344AK (not matched to a registry record) - Reported make and model: Robinson R-44 - Category: Helicopter - Serial number: 1004 - Airframe hours: 567 - Engines: LYCOMING O-540-F1B5 260 horsepower reciprocating - Damage: Substantial damage - Flight: Public aircraft, Public use - Operator: U.S. Geological Survey - Registered owner: Quicksilver Air Inc. - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, May 2, 2002, 10 hours before - Departed: PAIN, McKINLEY PARK, AK - Destination: AK - Flight plan: VFR ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 32; injuries: none; commercial, flight instructor; medical: class 2, valid medical--w/ waivers/lim; last flight review February 20, 2002; seat: right; flight hours: 1,965 total, 843 in this make and model, 1,909 as pilot in command, 86 in the last 90 days, 46 in the last 30 days, 8 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 135° at 5 knots, gusting 10 - Visibility: 30 statute miles - Lowest ceiling: none - Temperature: 52 °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 20020516009639A](https://openairdocs.org/incident/20020516009639A), May 16, 2002: Robsin R44, Cantwell, AK, No damage. (-23) Airman was operating the aircraft in an out of ground effect hover at near maximum power when he inadvertently allowed the rotor RPM to bleed below the… ## Docket (4 files) The files NTSB released with the investigation on October 29, 2002, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=54720. 783 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 304 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437633&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Pilot Statement (item 2, .PDF, 86 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40169984&FileExtension=.PDF&FileName=Pilot%20Statement-Master.PDF - Passenger Statement (item 3, .PDF, 89 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437634&FileExtension=.PDF&FileName=Passenger%20Statement-Redacted.PDF - Statement of Party Representatives to NTSB Investigation (item 4, .PDF, 304 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40437635&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-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.