# NTSB ANC15LA020: Cessna 170B, N4697C, Bettles, AK, April 13, 2015 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: April 12, 2015, 16:45 local (Apr 13, 2015, 00:45 UTC) - Place: Bettles, AK - Coordinates: 67.213058, -151.431671 - Nearby events: https://openairdocs.org/map.md?lat=67.2131&lon=-151.4317&mi=10 - Phase of flight: [Initial climb](https://openairdocs.org/ntsb-phases/350) (OpenAirDocs' grouping) - Defining event: [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 3 uninjured - Status: Completed, report June 1, 2016 - Report: Approved by Office Director - NTSB office: Alaska Regional Office - Parties: FAA - NTSB case key (mKey): 91013 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ANC15LA020 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/91013/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=91013 - Page: https://openairdocs.org/ntsb/ANC15LA020 ## Probable cause A total loss of engine power for reasons that could not be determined because postaccident engine examination and testing revealed no mechanical anomalies that would have precluded normal operation. ## 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: [Cessna 170B, 2 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=2072306), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Initial climb: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Cessna 170B, 5 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=2072306), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Initial climb: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Cessna 170B, 6 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=2072306), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Other: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 170B, 52 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072306), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The commercial pilot stated that, shortly after takeoff for the personal flight, when the airplane was between about 50 and 70 ft above ground level, a total loss of engine power occurred. After completing the engine failure emergency procedures checklist, the pilot lowered the airplane's nose and attempted to find a suitable landing area. When he determined that the airplane would not be able to reach the desired landing point, he arrested the descent, and the airplane settled into an area of densely populated birch trees along the side of a river. A postaccident examination of the airplane's systems and engine revealed no evidence of any preimpact mechanical anomalies. The engine was test run, and it operated through a full range of power settings with no anomalies noted. ## Factual narrative On April 12, 2015 about 1645 Alaska daylight time, a tailwheel-equipped, Cessna 170B airplane, N4697C, sustained substantial damage following a total loss of engine power shortly after takeoff from an unimproved ski airstrip about 20 miles north of Bettles, Alaska. The certificated commercial pilot and two passengers were not injured. The airplane was registered to a private individual, and operated by the pilot under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan had been filed. In an interview with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on April 13, 2015, the pilot stated that shortly after takeoff, between about 50 and 70 feet above ground level (agl), a total loss of engine power occurred. After completing the emergency procedures for an engine failure, the pilot lowered the nose of the airplane to find a suitable landing area. When he determined he was unable to reach the desired landing point, he arrested the descent and settled into an area of densely populated birch trees along the side of a river, sustaining substantial damage to the airplane. During a conversation with an NTSB investigator on April 24, 2015, the pilot stated that prior to takeoff, he was unable to check the fuel tanks for contamination using the wing tank fuel drain valves because they were frozen and inoperable. During a post accident aircraft examination, the carburetor was removed from the engine and the float bowl was examined. The float bowl was about 1/2 full with 100LL aviation fuel. The gascollator, electric fuel pump and fuel lines were then drained into a clean, clear container and no contamination was noted. The engine, a Lycoming O-360, was removed with the mounts attached, and transported to Alaskan Aircraft Engines, Inc., Anchorage, Alaska. On June 4 2015, the engine was mounted to a test stand and operated under the direction of an NTSB investigator. The engine ran without any observed anomalies, and produced full factory specified rpm. A drop of about 75 rpm was noted for the left magneto and about 100 rpm for the right magneto. A series of power adjustments from idle to full power were conducted with no hesitation in engine operation noted. The closest weather reporting facility is Bettles Airport, Bettles, approximately 20 miles south of the accident site. At 1553, an aviation routine weather report (METAR) from the Bettles Airport was reporting in part: wind from 150 degrees at 3 knots; sky condition, scattered at 3,000 feet agl, broken at 5,500 feet agl; visibility, 10 statute miles; temperature 19 degrees F; dew point 10 degrees F; barometric pressure 29.53inHg. ## Aircraft - Registration: [N4697C](https://openairdocs.org/deregistered/N4697C-2022-09-03), registration cancelled 2022-09-03, S/N 25641, built 1953 (OpenAirDocs) - Reported make and model: CESSNA 170B - Registry model: [Cessna 170B](https://openairdocs.org/model/cessna-170b) (registry code 2072306) (OpenAirDocs) - Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 25641 - Year built: 1953 - Airframe hours: 5529 - Engines: LYCOMING O-360-A1A 180 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Operator: Seth W. Mcmillan - Registered owner: Seth W. Mcmillan - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 14, 2014, 57 hours before - Departed: BTT, Bettles, AK - Destination: BTT, BETTLES, AK - Airport: BTT, Bettles - Equipment: Handheld GPS, Satellite tracking device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 38; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: airplane; medical: class 2, without waivers/limitations; last flight review February 2, 2015; seat: left; restraint: 4-point; flight hours: 2,465 total, 800 in this make and model, 2,220 as pilot in command, 75 in the last 90 days, 50 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 150° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: 5,500 ft broken - Temperature: 19 °F, dew point 10 °F - Altimeter: 29.53 inHg - Observed at: PABT, 18 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 20150412009269A](https://openairdocs.org/incident/20150412009269A), Apr 12, 2015: Cessna 170B, Bettles, AK, Substantial damage. On third takeoff off the day, at appproximately 50 feet of elevation engine lost power. ## Docket (3 files) The files NTSB released with the investigation on April 6, 2016, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=91013. 726 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 606 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40438551&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Engine Test Run Report (item 2, .PDF, 64 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40438552&FileExtension=.PDF&FileName=Engine%20Test%20Run%20Report-Master.PDF - Record of Conversation with NTSB (item 3, .PDF, 55 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40438553&FileExtension=.PDF&FileName=Record%20of%20Conversation%20with%20NTSB-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.