# Hydraulic, auxiliary system

- Type: NTSB finding subsection
- Path: [Aircraft](https://openairdocs.org/ntsb-findings/01) › [Aircraft systems](https://openairdocs.org/ntsb-findings/0102) › [Hydraulic power system](https://openairdocs.org/ntsb-findings/010229) › Hydraulic, auxiliary system
- NTSB code: 01022920
- Cases: 2
- In the probable cause: 2
- Fatal cases: 0
- All cases: https://openairdocs.org/ntsb-findings/01022920/cases.md
- Cases with it in the probable cause: https://openairdocs.org/ntsb-findings/01022920/cases.md?cause=1
- Page: https://openairdocs.org/ntsb-findings/01022920

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

- 2008: 1 / 1
- 2020: 1 / 1

## Defining events in these cases

- [Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333): 1 cases
- [Ground collision](https://openairdocs.org/ntsb-events/200): 1 cases

## Aircraft models (registry)

- [Sikorsky S-61N](https://openairdocs.org/model/sikorsky-s-61n): 1 cases

## Other findings in the same cases

- [Use of equip/system](https://openairdocs.org/ntsb-findings/02063015) (Personnel issues): 1 cases
- [Hydraulic, indicating system](https://openairdocs.org/ntsb-findings/01022930) (Aircraft): 1 cases
- [Hydraulic power system, general](https://openairdocs.org/ntsb-findings/01022900) (Aircraft): 1 cases

## Newest cases

- [NTSB DCA20LA100](https://openairdocs.org/ntsb/DCA20LA100), Apr 20, 2020: Sikorsky S61 (N908CH), Camp Dwyer, Afghanistan, substantial damage. Probable cause: Fatigue cracking of the auxiliary servo cylinder’s pedal damper check valve housing and its bolts, which caused the sudden and uncommanded movement of the helicopter’s left pedal and a subsequent…
- [NTSB NYC08LA091](https://openairdocs.org/ntsb/NYC08LA091), Feb 1, 2008: North American Rockwell NA-265-80 (N3RP), Ft. Lauderdale, FL, substantial damage. Probable cause: The depletion of pressure in the normal hydraulic system for an undetermined reason, and the pilots' failure to properly operate the emergency braking system. Contributing to the accident was 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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