# Sloped/uneven 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) › Sloped/uneven terrain - NTSB code: 03021017 - Cases: 270 - In the probable cause: 102 - Fatal cases: 13 - All cases: https://openairdocs.org/ntsb-findings/03021017/cases.md - Cases with it in the probable cause: https://openairdocs.org/ntsb-findings/03021017/cases.md?cause=1 - Page: https://openairdocs.org/ntsb-findings/03021017 ## Cases per year (in the probable cause / all) - 2008: 16 / 26 - 2009: 2 / 17 - 2010: 0 / 5 - 2011: 2 / 12 - 2012: 0 / 13 - 2013: 3 / 10 - 2014: 6 / 21 - 2015: 3 / 16 - 2016: 5 / 16 - 2017: 5 / 18 - 2018: 8 / 33 - 2019: 28 / 36 - 2020: 6 / 8 - 2021: 6 / 12 - 2022: 2 / 6 - 2023: 3 / 5 - 2024: 1 / 3 - 2025: 3 / 9 - 2026: 3 / 4 ## Defining events in these cases - [Loss of control on ground](https://openairdocs.org/ntsb-events/230): 85 cases - [Loss of engine power (total)](https://openairdocs.org/ntsb-events/341): 21 cases - [Runway excursion](https://openairdocs.org/ntsb-events/300): 20 cases - [Loss of control in flight](https://openairdocs.org/ntsb-events/240): 16 cases - [Collision during takeoff/land](https://openairdocs.org/ntsb-events/490): 15 cases - [Loss of engine power (partial)](https://openairdocs.org/ntsb-events/342): 12 cases - [Miscellaneous/other](https://openairdocs.org/ntsb-events/900): 10 cases - [Loss of lift](https://openairdocs.org/ntsb-events/500): 7 cases - [Hard landing](https://openairdocs.org/ntsb-events/092): 7 cases - [Nose over/nose down](https://openairdocs.org/ntsb-events/096): 6 cases ## Aircraft models (registry) - [Piper PA-18-150](https://openairdocs.org/model/piper-pa-18-150): 10 cases - [Robinson Helicopter R44 II](https://openairdocs.org/model/robinson-helicopter-r44-ii): 9 cases - [Cessna 172N](https://openairdocs.org/model/cessna-172n): 7 cases - [Piper PA-28-161](https://openairdocs.org/model/piper-pa-28-161): 5 cases - [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta): 4 cases - [Piper PA-28-140](https://openairdocs.org/model/piper-pa-28-140): 4 cases - [Cessna 172M](https://openairdocs.org/model/cessna-172m): 4 cases - [Schweizer 269C](https://openairdocs.org/model/schweizer-269c): 3 cases - [Piper PA-12](https://openairdocs.org/model/piper-pa-12): 3 cases - [Mooney M20J](https://openairdocs.org/model/mooney-m20j): 3 cases ## Other findings in the same cases - [Aircraft control](https://openairdocs.org/ntsb-findings/02063040) (Personnel issues): 124 cases - [Directional control](https://openairdocs.org/ntsb-findings/01062020) (Aircraft): 82 cases - [Decision making/judgment](https://openairdocs.org/ntsb-findings/02041520) (Personnel issues): 57 cases - [Not determined, general](https://openairdocs.org/ntsb-findings/05000000) (Not determined): 20 cases - [Tailwind](https://openairdocs.org/ntsb-findings/03034015) (Environmental issues): 18 cases - [Use of equip/system](https://openairdocs.org/ntsb-findings/02063015) (Personnel issues): 17 cases - [Gusts](https://openairdocs.org/ntsb-findings/03034045) (Environmental issues): 16 cases - [Altitude](https://openairdocs.org/ntsb-findings/01062012) (Aircraft): 14 cases - [Descent/approach/glide path](https://openairdocs.org/ntsb-findings/01062040) (Aircraft): 12 cases - [Delayed action](https://openairdocs.org/ntsb-findings/02041025) (Personnel issues): 11 cases ## Newest cases - [NTSB CEN26LA233](https://openairdocs.org/ntsb/CEN26LA233), Jun 3, 2026: Burkhart Grob Flugzeugbau G103 Twin Astir (N4101M), Gregory, MI, substantial damage. Probable cause: The flight instructor’s improper planning during the simulated aborted launch which resulted in a touchdown on unsuitable terrain. - [NTSB ERA26LA199](https://openairdocs.org/ntsb/ERA26LA199), Apr 20, 2026: Alexander Schleicher ASW 27-18 (N27CU), Greenwood, SC, substantial damage. Probable cause: The glider pilot’s encounter with a strong sink/loss of lift, which resulted in a forced landing to unsuitable terrain. - [NTSB WPR26LA146](https://openairdocs.org/ntsb/WPR26LA146), Apr 4, 2026: Bell Helicopter Textron 206L-1 (N5017G), Chimney Rock, MT, substantial damage. Probable cause: The pilot’s failure to maintain adequate clearance from the terrain while performing a low altitude circling takeoff maneuver, which resulted in a dynamic rollover. - [NTSB WPR26LA087](https://openairdocs.org/ntsb/WPR26LA087), Jan 19, 2026: Kitfox Series 7 (N775DZ), Lemmon Valley-Golden Valley, NV, substantial damage. Probable cause: The pilot’s inability to maintain clearance from terrain during a go-around. - [NTSB WPR26LA018](https://openairdocs.org/ntsb/WPR26LA018), Oct 9, 2025: Cessna 180 (N249MD), Imnaha, OR, substantial damage. Probable cause: The pilot’s continued application of brakes during an aborted takeoff in a tailwind on down-sloping terrain, which resulted in a nose-over. - [NTSB WPR26LA014](https://openairdocs.org/ntsb/WPR26LA014), Oct 4, 2025: Maye James A Just Aircraft Escapade (N80JM), Flanigan, NV, substantial damage. Probable cause: The pilot’s improper landing flare, which resulted in a hard landing. - [NTSB ANC25LA102](https://openairdocs.org/ntsb/ANC25LA102), Sep 5, 2025: American Champion 8GCBC (N242BC), Unalakleet, AK, substantial damage. Probable cause: The pilots encounter with an obstructed dip in the landing surface during the landing roll out on a remote airstrip, which resulted in a noseover. - [NTSB ANC25LA092](https://openairdocs.org/ntsb/ANC25LA092), Aug 22, 2025: Eurocopter AS 350 B2 (N149TH), Juneau, AK, substantial damage. Probable cause: The pilot’s failure to maintain adequate obstacle clearance during takeoff from uneven, snow-covered terrain in flat light conditions. - [NTSB WPR25LA226](https://openairdocs.org/ntsb/WPR25LA226), Jul 27, 2025: Cessna 182L (N42725), Tucson Estates, AZ, destroyed. Probable cause: The pilot’s inability to stop the airplane on the runway during a rejected takeoff for undetermined reasons, which resulted in the airplane’s impact with a ditch. - [NTSB ANC25LA074](https://openairdocs.org/ntsb/ANC25LA074), Jul 11, 2025: Dehavilland Beaver DHC-2 MK.1 (N109KS), Nelson Lagoon, AK, substantial damage. Probable cause: The pilot’s failure to maintain clearance from a creek bank while maneuvering to land. 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. --- 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.