# Mountainous/hilly terrain

- Type: NTSB finding subsection
- Path: [Environmental issues](https://openairdocs.org/ntsb-findings/03) › [Physical environment](https://openairdocs.org/ntsb-findings/0302) › [Terrain](https://openairdocs.org/ntsb-findings/030210) › Mountainous/hilly terrain
- NTSB code: 03021010
- Cases: 329
- In the probable cause: 127
- Fatal cases: 187
- All cases: https://openairdocs.org/ntsb-findings/03021010/cases.md
- Cases with it in the probable cause: https://openairdocs.org/ntsb-findings/03021010/cases.md?cause=1
- Page: https://openairdocs.org/ntsb-findings/03021010

## Cases per year (in the probable cause / all)

- 2008: 20 / 35
- 2009: 5 / 24
- 2010: 9 / 25
- 2011: 4 / 29
- 2012: 3 / 26
- 2013: 4 / 16
- 2014: 8 / 21
- 2015: 8 / 15
- 2016: 8 / 16
- 2017: 6 / 20
- 2018: 9 / 20
- 2019: 8 / 18
- 2020: 7 / 14
- 2021: 5 / 13
- 2022: 6 / 11
- 2023: 8 / 13
- 2024: 5 / 7
- 2025: 1 / 3
- 2026: 3 / 3

## Defining events in these cases

- [Controlled flight into terr/obj (CFIT)](https://openairdocs.org/ntsb-events/120): 110 cases
- [Loss of control in flight](https://openairdocs.org/ntsb-events/240): 46 cases
- [Low altitude operation/event](https://openairdocs.org/ntsb-events/220): 42 cases
- [VFR encounter with IMC](https://openairdocs.org/ntsb-events/401): 24 cases
- [Loss of engine power (total)](https://openairdocs.org/ntsb-events/341): 12 cases
- [Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470): 11 cases
- [Collision during takeoff/land](https://openairdocs.org/ntsb-events/490): 10 cases
- [Aerodynamic stall/spin](https://openairdocs.org/ntsb-events/241): 10 cases
- [Loss of lift](https://openairdocs.org/ntsb-events/500): 8 cases
- [Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342): 6 cases

## Aircraft models (registry)

- [Cirrus Design SR22](https://openairdocs.org/model/cirrus-design-sr22): 9 cases
- [Cessna 172N](https://openairdocs.org/model/cessna-172n): 8 cases
- [Cessna 172M](https://openairdocs.org/model/cessna-172m): 7 cases
- [Cessna 172S](https://openairdocs.org/model/cessna-172s): 6 cases
- [Piper PA-28-140](https://openairdocs.org/model/piper-pa-28-140): 5 cases
- [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150): 5 cases
- [Piper PA-12](https://openairdocs.org/model/piper-pa-12): 5 cases
- [Cessna 182P](https://openairdocs.org/model/cessna-182p): 5 cases
- [Beech A36](https://openairdocs.org/model/beech-a36): 5 cases
- [Air Tractor AT-802A](https://openairdocs.org/model/air-tractor-at-802a): 5 cases

## Other findings in the same cases

- [Decision making/judgment](https://openairdocs.org/ntsb-findings/02041520) (Personnel issues): 147 cases
- [Altitude](https://openairdocs.org/ntsb-findings/01062012) (Aircraft): 138 cases
- [Aircraft control](https://openairdocs.org/ntsb-findings/02063040) (Personnel issues): 70 cases
- [Monitoring environment](https://openairdocs.org/ntsb-findings/02021545) (Personnel issues): 35 cases
- [Below VFR minima](https://openairdocs.org/ntsb-findings/03035075) (Environmental issues): 34 cases
- [Airspeed](https://openairdocs.org/ntsb-findings/01062010) (Aircraft): 30 cases
- [Dark](https://openairdocs.org/ntsb-findings/03036020) (Environmental issues): 27 cases
- [Downdraft](https://openairdocs.org/ntsb-findings/03034035) (Environmental issues): 26 cases
- [High density altitude](https://openairdocs.org/ntsb-findings/03031020) (Environmental issues): 23 cases
- [Flight planning/navigation](https://openairdocs.org/ntsb-findings/02061025) (Personnel issues): 23 cases

## Newest cases

- [NTSB CEN26LA300](https://openairdocs.org/ntsb/CEN26LA300), Aug 21, 2026: Cessna T206H (N464PM), Marble, CO, substantial damage. Probable cause: The pilot's failure to maintain directional control during the final approach in variable and gusting wind conditions. Contributing to the accident were localized wind effects associated with…
- [NTSB WPR26LA234](https://openairdocs.org/ntsb/WPR26LA234), Jun 23, 2026: Piper PA-12 (N3013M), Dixie, ID, substantial damage. Probable cause: The pilot's delayed decision to initiate a go-around and subsequent failure to maintain clearance from rising terrain.
- [NTSB WPR26LA123](https://openairdocs.org/ntsb/WPR26LA123), Mar 10, 2026: Brunner Donald G Kitfox (N104DG), Rock Crossing, AZ, substantial damage. Probable cause: An encounter with a downdraft while maneuvering at a low altitude, which resulted in an impact with terrain.
- [NTSB ANC25LA085](https://openairdocs.org/ntsb/ANC25LA085), Aug 9, 2025: Dehavilland DHC-2 MK 1 (N232KT), Soldotna, AK, substantial damage. Probable cause: The pilot’s failure to maintain clearance from rising terrain while maneuvering at low altitude.
- [NTSB CEN25LA240](https://openairdocs.org/ntsb/CEN25LA240), Jul 7, 2025: Cub Crafters CCK-1865 (N952SA), La Garita, CO, substantial damage. Probable cause: The pilot’s failure to maintain clearance from terrain while maneuvering at low altitude in mountainous terrain. Contributing was the pilot’s inadequate preflight planning and aeronautical decision…
- [NTSB WPR25LA080](https://openairdocs.org/ntsb/WPR25LA080), Jan 2, 2025: Piper PA-32-300 (N4151R), Round Mountain, NV, substantial damage, 1 fatal. Probable cause: Impact with mountainous terrain for reasons that could not be determined due to a lack of available evidence.
- [NTSB CEN25FA047](https://openairdocs.org/ntsb/CEN25FA047), Nov 23, 2024: Cessna 182T (N434CP), Drake, CO, destroyed, 2 fatal. Probable cause: The pilot’s failure to maintain airplane control while maneuvering in mountainous terrain. Contributing was mountain wave turbulence in the area.
- [NTSB ERA25FA037](https://openairdocs.org/ntsb/ERA25FA037), Oct 31, 2024: Cessna 150F (N8110S), Wilder, TN, destroyed, 1 fatal. Probable cause: The student pilot’s decision to continue the visual flight rules flight into instrument meteorological conditions at night, which resulted in controlled flight into terrain.
- [NTSB WPR25LA006](https://openairdocs.org/ntsb/WPR25LA006), Oct 8, 2024: Agustawestland AW109SP (N631HC), Kamas, UT, substantial damage. Probable cause: The pilot’s exceedance of the helicopter’s available power while landing in a confined area, which resulted in a loss of tail rotor effectiveness and a hard landing.
- [NTSB WPR24FA298](https://openairdocs.org/ntsb/WPR24FA298), Sep 6, 2024: Boeing A75L3 (N53466), Yacolt, WA, substantial damage, 1 fatal. Probable cause: The pilot’s exceedance of the airplane’s critical angle of attack while maneuvering at a low altitude in mountainous terrain in moderately high density altitude conditions, resulting in an…

NTSB has coded findings and defining events since 2008; earlier cases used its older occurrence and cause codes and aren't counted.

Findings: https://openairdocs.org/ntsb-findings.md. Defining events: https://openairdocs.org/ntsb-events.md. Phases of flight: https://openairdocs.org/ntsb-phases.md. Every investigation, filtered by finding, event, phase, state, year or model: https://openairdocs.org/ntsb.md (for example ?state=MI&fatal=1).

NTSB's definitions: Accident and incident, 49 CFR 830.2 (https://www.ecfr.gov/current/title-49/subtitle-B/chapter-VIII/part-830/subpart-A/section-830.2), CICTT occurrence categories (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/OccurrenceCategoryDefinitions.pdf), CICTT phases of flight (PDF) (https://www.ntsb.gov/safety/data/Documents/datafiles/PhaseofFlightDefinitions.pdf), and NTSB coding manual, before 2008 (PDF) (https://www.ntsb.gov/GILS/Documents/codman.pdf). NTSB publishes no definitions for its findings, only their names.

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