# NTSB GAA15CA282: Cessna 170B, N2528C, Arctic Village, AK, September 24, 2015 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Data collection · Final report - Date: September 24, 2015, 13:00 local (21:00 UTC) - Place: Arctic Village, AK - Coordinates: 68.090202, -145.600128 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=68.0902&lon=-145.6001&mi=10 - Phase of flight: [Takeoff](https://openairdocs.org/ntsb-phases/300) (OpenAirDocs' grouping) - Defining event: [Takeoff: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) - Highest injury: Minor injuries - Injuries: 1 minor, 1 uninjured - Status: Completed, report December 3, 2015 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA Fairbanks FSDO - NTSB case key (mKey): 92082 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA15CA282 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/92082/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=92082 - Page: https://openairdocs.org/ntsb/GAA15CA282 ## Probable cause The pilot exceeded the critical angle of attack during takeoff, which resulted in an aerodynamic stall and a collision with 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: [Cessna 170B, 91 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2072306), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Performance/control parameters: angle of attack](https://openairdocs.org/ntsb-findings/01062042): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Cessna 170B, 5 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md?model=2072306), [All aircraft, 990 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Takeoff: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) (defining event); cases with it: [Cessna 170B, 9 cases](https://openairdocs.org/ntsb-events/241/sequence.md?model=2072306), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Takeoff: Loss of control in flight](https://openairdocs.org/ntsb-events/240); cases with it: [Cessna 170B, 19 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=2072306), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Takeoff: 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 pilot reported that after taking off from a frozen gravel bar by a river in remote wilderness, the airplane stalled. The left main landing gear struck the edge of the cut bank and the left wing impacted the ground. The fuselage then impacted the top of the bank and spun counterclockwise. The pilot stated that the left wing was separated from the fuselage and the fuselage had sustained substantial damage. The pilot reported there were no pre-impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. ## Factual narrative The pilot reported that after taking off from a frozen gravel bar by a river in remote wilderness, the airplane stalled. The left main landing gear struck the edge of the cut bank and the left wing impacted the ground. The fuselage then impacted the top of the bank and spun counterclockwise. The pilot stated that the left wing was separated from the fuselage and the fuselage had sustained substantial damage. The pilot reported there were no pre-impact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. The pilot reported as a safety recommendation, "I would take off empty or with minimal known weight to ensure that the aircraft would perform as planned. I could then land to reload, or if partially loaded, fly to another gravel bar that was longer, and stage from there, returning to the point of origin empty, and then continue to shuttle gear and people. That first flight would have been better planned without another person on board, not just due to weight, but due to risk to that person." ADDITIONAL INFORMATION Alaska Off Airport Flight Operations The Alaskan Aviation Safety Foundation has published a safety briefing Off Airport Landings. This safety briefing discusses off airport takeoff and landing operations. This safety briefing states in part; When flying very low and slow on takeoff or landing approach, do not fly over an abrupt drop-off such as a cut bank or steep lake shore. You can abruptly lose ground effect and begin to settle. This safety briefing also lists considerations when selecting off airport takeoff and landing sites and states in part; Airplane load: Obviously, ever gram counts. Density altitude: You don't have to go into the mountains to get a change in density altitude. Ground drag: A thawed gravel bar, even a dry one, presents considerably more drag than a frozen one. Departure obstacles: An obvious thing, but if you've been flying off river bars in ground effect, it's easy to underestimate the additional space needed to clear a 15 foot obstacle. ## Aircraft - Registration: [N2528C](https://openairdocs.org/deregistered/N2528C-2019-11-01), registration cancelled 2019-11-01, S/N 26172, built 1954 (OpenAirDocs) - Reported make and model: CESSNA 170B (UNDESIGNAT) - 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: 26172 - Year built: 1954 - Airframe hours: 2653 - Engines: Lycoming O-320-D1A 160 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, January 7, 2015 - Departed: FAI, FAIRBANKS, AK - Destination: FAI, FAIRBANKS, AK ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 57; injuries: minor; private; airplane ratings: single-engine land; medical: class 3, without waivers/limitations; last flight review July 8, 2014; seat: left; restraint: 4-point; flight hours: 355 total, 110 in this make and model, 316 as pilot in command ## Weather - Conditions: Visual (VMC), Day - Wind: 60° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: 1,700 ft overcast - Temperature: 21 °F, dew point 12 °F - Altimeter: 29.84 inHg - Observed at: PARC, 78 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 20150924016519A](https://openairdocs.org/incident/20150924016519A), Sep 24, 2015: Cessna 170B, Atrctic Village, AK, Substantial damage. PIC was on take-off roll. At the point of rotation and a speed of appx 45 mph, the aircraft stopped gaining altitude. Wind flags beside the gravel bar… ## Docket (2 files) The files NTSB released with the investigation on November 10, 2015, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=92082. 3.2 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 2.8 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40433769&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Accident Photos (item 2, .PDF, 486 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40433770&FileExtension=.PDF&FileName=Accident%20Photos%20-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.