# NTSB ANC11LA099: Robinson Helicopter R22 Beta, N169CW, Unalaska, AK, August 30, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 30, 2011, 13:30 local (21:30 UTC) - Place: Unalaska, AK - Coordinates: 53.383335, -167.641662 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=53.3833&lon=-167.6417&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report May 15, 2012 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA Anchorage FSDO - NTSB case key (mKey): 81754 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC11LA099 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/81754/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=81754 - Page: https://openairdocs.org/ntsb/ANC11LA099 ## Probable cause A loss of engine power in cruise flight for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Robinson Helicopter R22 BETA, 16 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=7640110), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) - [Temp/humidity/pressure: conducive to carburetor icing](https://openairdocs.org/ntsb-findings/03031030): Environmental issues › Conditions/weather/phenomena · Not specified; cases with it: [Robinson Helicopter R22 BETA, 9 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md?model=7640110), [All aircraft, 435 cases](https://openairdocs.org/ntsb-findings/03031030/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Robinson Helicopter R22 BETA, 18 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7640110), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Autorotation: Ditching](https://openairdocs.org/ntsb-events/441); cases with it: [Robinson Helicopter R22 BETA, 3 cases](https://openairdocs.org/ntsb-events/441/sequence.md?model=7640110), [All aircraft, 186 cases](https://openairdocs.org/ntsb-events/441/sequence.md) ## Analysis The pilot reported that, during cruise flight, the engine ran rough for about three engine revolutions before losing total power. The pilot entered an emergency autorotation and landed the helicopter in a shallow bay. Postaccident examination of the helicopter did not reveal any mechanical anomalies that would have precluded normal operation; however, a detailed engine examination was not completed. According to a carburetor icing probability chart, conditions at the time of the accident were conducive to severe carburetor icing at both cruise and glide power settings. Although carburetor icing was a possible initiating event for the loss of engine power, carburetor icing could not be determined. ## Factual narrative On August 30, 2011, about 1330 Alaska daylight time, a Robinson R22 Beta II helicopter, N169CW, sustained substantial damage following a loss of engine power and subsequent emergency landing approximately 60 miles southwest of Unalaska, Alaska. The helicopter was registered to Bering Pacific Ranches, LTD, and operated by the pilot as a personal flight under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the flight, and no flight plan was filed. The flight originated from the Unalaska Airport, Unalaska, Alaska, about 1230. The pilot reported that approximately 9 miles from his destination, the engine ran rough for about three engine revolutions before losing total power. He entered an emergency autorotation, and landed the helicopter in a shallow bay, approximately 150 feet from the shoreline. After contacting the water, the helicopter rolled to the right, and sank in shallow water. The pilot reported substantial damage to the tail rotor drive system. A Federal Aviation Administration inspector traveled to the operator's hangar, and examined the helicopter. No mechanical anomalies were noted that would have precluded normal operation. The operator stated that the helicopter was going to be sent to a facility for a more detailed inspection, but as of this writing, no further inspection has been performed. At 1358, the nearest weather reporting facility to the accident site was reporting the temperature as 14 degrees Celsius, and the dew point as 9 degrees Celsius. According to a carburetor icing probability chart, serious icing conditions existed at cruise and glide power settings. ## Aircraft - Registration: [N169CW](https://openairdocs.org/deregistered/N169CW-2017-08-07), registration cancelled 2017-08-07, S/N 3002, built 1999 (OpenAirDocs) - Reported make and model: ROBINSON HELICOPTER R22 BETA - Registry model: [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta) (registry code 7640110) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 3002 - Engines: LYCOMING O&VO-360 SER 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Bering Pacific Ranches Ltd - Registered owner: Bering Pacific Ranches Ltd - Departed: DUT, Unalaska, AK - Destination: Fort Glenn, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 23; injuries: none; private; medical: class 3, without waivers/limitations; seat: right; flight hours: 800 total, 750 in this make and model, 740 as pilot in command, 200 in the last 90 days, 25 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 30° at 10 knots - Visibility: 10 statute miles - Lowest ceiling: 9,000 ft broken - Temperature: 57 °F, dew point 48 °F - Altimeter: 29.87 inHg - Observed at: PADU, 50 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 20110830022459A](https://openairdocs.org/incident/20110830022459A), Aug 30, 2011: Robinson Helicopter R22 BETA, Dutch Harbor, AK, Substantial damage. According to the airman, he took off from Dutch Harbor Airport to fly back to the bering pacific ranch his employer and owenr of the aircraft. One hour into… ## Other investigations on N169CW (1) 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. - [NTSB LAX00LA262](https://openairdocs.org/ntsb/LAX00LA262), Jul 14, 2000: Robinson R-22 Beta (N169CW), Lake Piru, CA, substantial damage. Probable cause: The improper use of the cyclic control by the pilot under instruction, and the flight instructor's lack of remedial action. ## Docket (3 files) The files NTSB released with the investigation on April 6, 2012, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=81754. 635 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 529 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40365682&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - FAA Inspector Correspondence (item 2, .PDF, 30 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40365683&FileExtension=.PDF&FileName=FAA%20Inspector%20Correspondence-Redacted.PDF - Carburetor Icing Probability Chart (item 3, .PDF, 76 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40365684&FileExtension=.PDF&FileName=Carburetor%20Icing%20Probability%20Chart-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.