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CEN22FA035 · Air Tractor Inc AT-802A

16 Nov 2021 · Estes Park, CO, United States

CO Fire Aviation Air Tractor Inc AT-802A · Accident: turbulence encounter while maneuvering

From Northern Colorado Regional Airport (FNL) to an unrecorded destination

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Event

NTSB case
CEN22FA035
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
1 · all aircraft and ground
Ground fatalities
Unknown
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

Air Tractor Inc AT-802A

Aircraft type
Air Tractor AT-802
Category
Airplane
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N802NZ
Onboard fatalities
Unknown
Route
From Northern Colorado Regional Airport (FNL), Fort Collins, COTo not recorded
Aircraft age
About 6 years (built 2015)
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 137: Agricultural
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
Maneuvering · low-altitude flying
Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
Turbulence encounter
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Substantial

Cause areas

  • Aircraft › Aircraft oper/perf/capability
  • Environmental issues › Conditions/weather/phenomena

Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.

NTSB narrative

The aerial firefighting flight was approaching the intended drop location when the airplane rolled inverted, descended, and impacted terrain. The airplane wreckage displayed features of a low-speed, nose-down impact with the engine producing power. The airplane sustained substantial damage to the fuselage, wings, and empennage. Recorded data showed decreasing indicated airspeed and increasing engine power toward the end of the flight. Postaccident examination of the airplane revealed no mechanical anomalies that would have precluded normal operation. The accident site was located on the eastern slope of a high mountain range, and west winds gusting to near 30 knots were reported near the time of the accident. An animation of satellite imagery showed that most of the clouds west and east of the accident site did not propagate eastward with time with the mean wind but remained relatively stationary, which was consistent with mountain wave activity. Low cloud bands immediately south of the accident also remained relatively stationary and were likely rotor clouds, a type of cloud associated with severe or greater turbulence. It is likely the airplane encountered severe to extreme low altitude turbulence associated with rotor clouds, which resulted in the loss of control.

Probable cause

The airplane’s encounter with severe to extreme turbulence associated with mountain wave rotor cloud activity, which resulted in loss of airplane control.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record CEN22FA035
Event ID
20211117104254
Case number
CEN22FA035
Dataset
full-current
Source SHA-256
5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: local date, investigation status, coordinates, cause areas. Values present in the bulk record are kept.
  • The date is the local date; the NTSB stores the UTC date 2021-11-17.
  • API snapshot SHA-256: 3dc32025c4de21d1cc025bb61d3bbdb2a3ff3c4a8fba94131942816c3a3ade35; retrieved 2026-09-15T07:37:34.292Z.