# Pressure/environ sys malf/fail

- Type: NTSB defining event
- NTSB code: 331
- CICTT category: System/Component Failure (Non-Powerplant)
- Defining event in: 111 cases
- In the sequence of: 115 cases
- Fatal cases: 1
- All cases: https://openairdocs.org/ntsb.md?event=331
- Page: https://openairdocs.org/ntsb-events/331

## Cases per year (defining / in the sequence)

- 2008: 0 / 1
- 2009: 0 / 1
- 2010: 3 / 3
- 2011: 2 / 2
- 2012: 7 / 7
- 2013: 2 / 2
- 2014: 3 / 4
- 2015: 3 / 3
- 2016: 4 / 5
- 2017: 11 / 11
- 2018: 13 / 13
- 2019: 3 / 3
- 2020: 4 / 4
- 2021: 11 / 11
- 2022: 11 / 11
- 2023: 7 / 7
- 2024: 11 / 11
- 2025: 10 / 10
- 2026: 6 / 6

## Phase of flight

- Enroute-cruise: 28 cases
- Enroute: 27 cases
- Enroute-climb to cruise: 21 cases
- Initial climb: 15 cases
- Enroute-descent: 13 cases
- Approach: 2 cases
- Landing: 1 cases
- Maneuvering-low-alt flying: 1 cases
- Enroute-change of cruise level: 1 cases
- Takeoff-rejected takeoff: 1 cases

## In the probable cause of these cases

- [Decision making/judgment](https://openairdocs.org/ntsb-findings/02041520) (Personnel issues): 2 cases
- [Not determined, general](https://openairdocs.org/ntsb-findings/05000000) (Not determined): 1 cases
- [Adequacy of policy/proc](https://openairdocs.org/ntsb-findings/04021015) (Organizational issues): 1 cases
- [Sign/marker](https://openairdocs.org/ntsb-findings/03022015) (Environmental issues): 1 cases
- [Incorrect action selection](https://openairdocs.org/ntsb-findings/02041010) (Personnel issues): 1 cases
- [Other loss of consciousness](https://openairdocs.org/ntsb-findings/02012055) (Personnel issues): 1 cases
- [Hypoxia/anoxia](https://openairdocs.org/ntsb-findings/02012035) (Personnel issues): 1 cases
- [Hoses and tubes](https://openairdocs.org/ntsb-findings/01071410) (Aircraft): 1 cases
- [Fuel](https://openairdocs.org/ntsb-findings/01071010) (Aircraft): 1 cases
- [Dynamic load](https://openairdocs.org/ntsb-findings/01062032) (Aircraft): 1 cases

## Aircraft models (registry)

- [Gulfstream Aerospace G-IV](https://openairdocs.org/model/gulfstream-aerospace-g-iv): 2 cases
- [Socata TBM 700](https://openairdocs.org/model/socata-tbm-700): 1 cases
- [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44): 1 cases
- [North American NA-265-80](https://openairdocs.org/model/north-american-na-265-80): 1 cases
- [Airbus A320-233](https://openairdocs.org/model/airbus-a320-233): 1 cases
- [Cessna 501](https://openairdocs.org/model/cessna-501): 1 cases
- [Cessna 172S](https://openairdocs.org/model/cessna-172s): 1 cases
- [Bombardier CL-600-2D24](https://openairdocs.org/model/bombardier-cl-600-2d24): 1 cases
- [Bombardier CL-600-2C10](https://openairdocs.org/model/bombardier-cl-600-2c10): 1 cases
- [Boeing 787-9](https://openairdocs.org/model/boeing-787-9): 1 cases

## Newest cases

- [NTSB DCA27LA013](https://openairdocs.org/ntsb/DCA27LA013), Oct 17, 2026: Bombardier CL-600-2D24 (N574NN), St. Louis, MO, no damage, investigation ongoing
- [NTSB DCA26WA376](https://openairdocs.org/ntsb/DCA26WA376), Sep 5, 2026: Boeing 737 (YV630T), La Chinita, Venezuela, incident, no damage
- [NTSB DCA26WA337](https://openairdocs.org/ntsb/DCA26WA337), Aug 13, 2026: Boeing 737 (9H-QEP), El Prat de Llobregat, Spain, incident
- [NTSB DCA26WA234](https://openairdocs.org/ntsb/DCA26WA234), Jun 4, 2026: Embraer ERJ190 (VH-XFM), Connellan, Australia, incident
- [NTSB ENG26WA024](https://openairdocs.org/ntsb/ENG26WA024), May 27, 2026: Gulfstream Aerospace G-IV (N899AL), Dushanbe, Tajikistan, incident, no damage
- [NTSB DCA26WA157](https://openairdocs.org/ntsb/DCA26WA157), Mar 9, 2026: Embraer ERJ190 (XA-ACE), Minatitlan, Mexico, incident, minor damage
- [NTSB DCA26WA057](https://openairdocs.org/ntsb/DCA26WA057), Dec 3, 2025: Boeing 767 (9M-RXE), Nan Ning Shi, China, incident, no damage
- [NTSB DCA26WA038](https://openairdocs.org/ntsb/DCA26WA038), Nov 8, 2025: Embraer ERJ170 (C-FEKJ), Toronto, Canada, occurrence, no damage
- [NTSB DCA26WA020](https://openairdocs.org/ntsb/DCA26WA020), Oct 21, 2025: Boeing 737 (9M-MXR), Bintulu, Malaysia, incident, no damage
- [NTSB DCA26WA006](https://openairdocs.org/ntsb/DCA26WA006), Sep 22, 2025: Boeing 737 (ZS-SJU), Cape Town, South Africa, incident

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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