# NTSB GAA19CA432: Aviat A1, N137C, Ennis, MT, July 17, 2019 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Data collection · Final report - Date: July 17, 2019, 08:28 local (14:28 UTC) - Place: Ennis, MT - Coordinates: 45.344132, -111.72735 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.3441&lon=-111.7274&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report April 13, 2020 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 99879 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA19CA432 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99879/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99879 - Page: https://openairdocs.org/ntsb/GAA19CA432 ## Probable cause The pilot's exceedance of the airplane's critical angle of attack while turning at low altitude, which resulted in an aerodynamic stall. Contributing to the accident was the pilot's distraction due to looking at wildlife. ## 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: [Aviat A-1A, 2 cases](https://openairdocs.org/ntsb-findings/01062042/cases.md?model=2210405), [All aircraft, 991 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: [Aviat A-1A, 7 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=2210405), [All aircraft, 9,308 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Attention/monitoring: attention](https://openairdocs.org/ntsb-findings/02021510): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Aviat A-1A, 1 case](https://openairdocs.org/ntsb-findings/02021510/cases.md?model=2210405), [All aircraft, 227 cases](https://openairdocs.org/ntsb-findings/02021510/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241) (defining event); cases with it: [Aviat A-1A, 2 cases](https://openairdocs.org/ntsb-events/241/sequence.md?model=2210405), [All aircraft, 1,530 cases](https://openairdocs.org/ntsb-events/241/sequence.md) - [Maneuvering-low-alt flying: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Aviat A-1A, 5 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=2210405), [All aircraft, 10,152 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The pilot reported that he was conducting an aerial survey to spot bears. After spotting bears, he flew multiple low-altitude passes to maintain sight of the bears. While maneuvering uphill at a low altitude, his attention was drawn to the bears and away from terrain. When he regained focus, he decided to turn the airplane right, away from rising terrain, but about 90º into the turn, the airplane descended and impacted terrain, and a postcrash fire ensued. The airplane sustained substantial damage to the wings and fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot added that he should have let the observer observe the bears during the low passes. ## Factual narrative The pilot of the tailwheel equipped airplane reported that he was contracted for an aerial survey to spot bears. After spotting bears, he flew multiple low altitude passes to maintain sight of the bears. While maneuvering uphill at a low altitude, his attention was "drawn into the visual of the bear and cubs" and away from the terrain. When he regained focus, he decided to turn the airplane to the right, away from rising terrain, but about 90º into the turn, the airplane descended, impacted the terrain, and a post-crash fire ensued. The airplane sustained substantial damage to the wings and fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot added that he should have let the observer examine the bears during the low passes. ## Aircraft - Registration: [N137C](https://openairdocs.org/deregistered/N137C-2019-11-04), registration cancelled 2019-11-04, S/N 1453, built 1999 (OpenAirDocs) - Reported make and model: Aviat A1 (A) - Registry model: [Aviat A-1A](https://openairdocs.org/model/aviat-a-1a) (registry code 2210405) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: 1453 - Year built: 1999 - Airframe hours: 3525 - Engines: Lycoming O-360-AIP 180 horsepower reciprocating - Damage: Destroyed - Fire: On-Ground - Flight: Part 135 - Airworthiness certificate: Standard, Normal - Last inspection: 100 hour, June 20, 2019 - Departed: BZN, Bozeman, MT - Destination: BZN, Bozeman, MT - Flight plan: Company VFR - Equipment: Stall warning system, Satellite tracking device ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 56; injuries: minor; commercial, airline transport, flight instructor; airplane ratings: single-engine land, single-engine sea, multi-engine land; instrument ratings: airplane, helicopter; medical: class 2, with waivers/limitations; last flight review April 4, 2019; seat: front; restraint: 5-point; flight hours: 18,000 total, 500 in this make and model, 17,500 as pilot in command, 120 in the last 90 days, 40 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 70 °F - Observed at: KRXE, 37 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 20190717011989A](https://openairdocs.org/incident/20190717011989A), Jul 17, 2019: Aviat Aircraft Inc A-1A, Ennis, MT, Substantial damage. On July 17, 2019, at 0952 local time, an Aviat Aircraft Inc., husky A-1A, N137C, registered to [privacy data omitted] northern wings aviation LLC, was flying a… ## Docket (2 files) The files NTSB released with the investigation on January 9, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99879. 1.1 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 914 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479737&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Accident Photo (item 2, .PDF, 183 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479738&FileExtension=.PDF&FileName=Accident%20Photo-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.