# NTSB GAA18CA214: Cessna 170, N4133V, Big Lake, AK, April 9, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: April 8, 2018, 19:30 local (Apr 9, 2018, 03:30 UTC) - Place: Big Lake, AK - Coordinates: 61.568889, -149.851104 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=61.5689&lon=-149.8511&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report July 5, 2018 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 97052 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA18CA214 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/97052/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=97052 - Page: https://openairdocs.org/ntsb/GAA18CA214 ## Probable cause The pilot’s exceedance of the airplane’s critical angle of attack, which resulted in an aerodynamic stall. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters: angle of attack](https://openairdocs.org/ntsb-findings/01062042): Aircraft › Aircraft oper/perf/capability · Capability exceeded (probable cause); cases with it: [Cessna 170, 4 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md?model=2072302), [All aircraft, 990 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Cessna 170, 17 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2072302), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Object/animal/substance: snow/ice](https://openairdocs.org/ntsb-findings/03022060): Environmental issues › Physical environment · Contributed to outcome; cases with it: [Cessna 170, 1 case](https://openairdocs.org/ntsb-findings/03022060/cases.md?model=2072302), [All aircraft, 67 cases](https://openairdocs.org/ntsb-findings/03022060/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Cessna 170, 7 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=2072302), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Approach: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241); cases with it: [Cessna 170, 4 cases](https://openairdocs.org/ntsb-events/241/sequence.md?model=2072302), [All aircraft, 1,529 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Landing-flare/touchdown: Runway excursion](https://openairdocs.org/ntsb-events/300); cases with it: [Cessna 170, 7 cases](https://openairdocs.org/ntsb-events/300/sequence.md?model=2072302), [All aircraft, 3,643 cases](https://openairdocs.org/ntsb-events/300/sequence.md) - [Landing: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Cessna 170, 15 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2072302), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) - [Post-impact: Fire/smoke (post-impact)](https://openairdocs.org/ntsb-events/170); cases with it: [Cessna 170, 1 case](https://openairdocs.org/ntsb-events/170/sequence.md?model=2072302), [All aircraft, 354 cases](https://openairdocs.org/ntsb-events/170/sequence.md) ## Analysis The pilot reported that, during the approach to land on a gravel airstrip, he increased engine power to "extend the approach," the airplane pitched up in a nose-high attitude, aerodynamically stalled, and yawed to the right. Subsequently, the airplane impacted a snowbank to the right side of the airstrip. A postcrash fire destroyed the airplane. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. ## Factual narrative The pilot reported that, during the approach to land on a gravel airstrip, he increased engine power to "extend the approach", the airplane pitched up in a nose high attitude, aerodynamically stalled and yawed to the right. Subsequently, the airplane impacted a snowbank to the right side of the airstrip. A postcrash fire destroyed the airplane. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. ## Aircraft - Registration: [N4133V](https://openairdocs.org/deregistered/N4133V-2021-07-03), registration cancelled 2021-07-03, S/N 18465, built 1948 (OpenAirDocs) - Reported make and model: CESSNA 170 (UNDESIGNAT) - Registry model: [Cessna 170](https://openairdocs.org/model/cessna-170) (registry code 2072302) (OpenAirDocs) - Registry engine: [Continental C145 series](https://openairdocs.org/engine/continental-c145-series) (registry code 17012, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 18465 - Year built: 1948 - Airframe hours: 3483.5 - Engines: CONT MOTOR C145 SERIES 145 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Instructional, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 26, 2017 - Departed: BGQ, BIG LAKE, AK - Destination: Big Lake, AK - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 79; injuries: none; flight instructor, commercial; airplane ratings: single-engine sea, multi-engine land, single-engine land; instrument ratings: airplane; medical: class 3, without waivers/limitations; seat: left; flight hours: 9,000 total, 3 in this make and model, 9,000 as pilot in command, 6 in the last 90 days, 6 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 60° at 7 knots - Visibility: 10 statute miles - Temperature: 48 °F, dew point 19 °F - Altimeter: 29.70 inHg - Observed at: PAWS, 9 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 20180408010469A](https://openairdocs.org/incident/20180408010469A), Apr 8, 2018: Cessna 170, Big Lake, AK, Destroyed. Pilot statement: On initial approach to landing good line up, good altitude, full trim full flaps. As approached end of runway, it appeared a bit low. Added a… ## Docket (2 files) The files NTSB released with the investigation on June 12, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=97052. 1.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40463914&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Accident Picture (item 2, .PDF, 1 photo, 515 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40463915&FileExtension=.PDF&FileName=Accident%20Picture-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.