# NTSB CEN21LA244: Dehavilland DHC-2 MK.I, N218RD, Oak Island, MN, May 22, 2021

- Type: NTSB accident investigation
- Classification: Accident · Serious injuries · Class 3 · Limited · Final report
- Date: May 22, 2021, 18:30 local (23:30 UTC)
- Place: Oak Island, MN
- Coordinates: 49.314838, -94.857267 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=49.3148&lon=-94.8573&mi=10
- Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping)
- Defining event: [Landing: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330)
- Highest injury: Serious injuries
- Injuries: 1 serious, 2 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 3
- NTSB office: Central Region
- Parties: FAA
- NTSB case key (mKey): 103181
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN21LA244
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/103181/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=103181
- Page: https://openairdocs.org/ntsb/CEN21LA244

## Probable cause

The failure of an O-ring in the landing gear system, which resulted in the inadvertent extension of the main wheel in the amphibious float. Contributing to the accident was the pilot’s decision to depart with a known hydraulic leak in the landing gear system.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Landing gear system: gear extension and retract sys](https://openairdocs.org/ntsb-findings/01023230): Aircraft › Aircraft systems · Malfunction (probable cause); cases with it: [Dehavilland DHC-2 MK.I, 1 case](https://openairdocs.org/ntsb-findings/01023230/cases.md?model=2808007), [All aircraft, 416 cases](https://openairdocs.org/ntsb-findings/01023230/cases.md)
- [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Dehavilland DHC-2 MK.I, 2 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=2808007), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md)
- [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Dehavilland DHC-2 MK.I, 1 case](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=2808007), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Landing: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Dehavilland DHC-2 MK.I, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=2808007), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md)
- [Landing: Landing gear not configured](https://openairdocs.org/ntsb-events/095); cases with it: [Dehavilland DHC-2 MK.I, 1 case](https://openairdocs.org/ntsb-events/095/sequence.md?model=2808007), [All aircraft, 584 cases](https://openairdocs.org/ntsb-events/095/sequence.md)

## Analysis

Before the flight, the pilot added hydraulic fluid to the reservoir due to a known leak in the airplane’s amphibious float landing gear system. At some point during the flight, the left rear wheel extended and protruded from the float. The pilot was unaware of the wheel position and landed on the water near his residence. During the water landing, the wheel contacted the water, and the airplane’s nose and propeller assembly immediately went into the water. The pilot and passengers exited the airplane, and the airplane subsequently flipped over. During the accident sequence, one passenger sustained vertebrae fractures, and the airplane sustained minor damage. Due to the remote accident location, the airplane was not examined; however, the pilot provided photos of the landing gear system problem area and a short video demonstrating the leak in the system. According to the pilot, the leak was the result of a failed O-ring in the lower hydraulic fitting on the jack assembly.

## Factual narrative

On May 22, 2021, about 1830 central daylight time, a de Havilland DHC-2, N218RD, sustained minor damage when it was involved in an accident near Oak Island, Minnesota. The pilot and one passenger were not injured, and one passenger sustained serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to local authorities who spoke with the pilot/owner after the accident, before the flight, the pilot added hydraulic fluid to the reservoir due to a known leak in the amphibious float landing gear system. At some point during the flight, the left rear wheel extended and protruded from the float. The pilot was unaware of the wheel position and landed on the water near his residence. During the water landing, the extended wheel contacted the water, and the airplane’s nose and propeller assembly immediately went into the water. The pilot and passengers exited the airplane, and the airplane subsequently flipped over. During the accident sequence, one passenger sustained vertebrae fractures. Due to the remote accident location, the airplane was not examined by the National Transportation Safety Board or the Federal Aviation Administration. The pilot provided photos of the landing gear system problem area and a short video demonstrating the leak in the system. According to the pilot, the leak was the result of a failed o-ring in the lower hydraulic fitting on the jack assembly. The pilot reported the airplane’s maintenance records were lost in the water following the accident. The most recent maintenance could not be determined.

## Aircraft

- Registration: [N218RD](https://openairdocs.org/aircraft/N218RD), registered now, S/N 50, built 1949 (OpenAirDocs)
- Reported make and model: DEHAVILLAND DHC-2 MK.I
- Registry model: [Dehavilland DHC-2 MK.I](https://openairdocs.org/model/dehavilland-dhc-2-mk-i) (registry code 2808007) (OpenAirDocs)
- Registry engine: [Pratt & Whitney R-985-AN-14B](https://openairdocs.org/engine/pratt-whitney-r-985-an-14b) (registry code 51654, reciprocating) (OpenAirDocs)
- Category: Airplane
- Serial number: 50
- Year built: 1949
- Engines: Pratt & Whitney R-985-AN-14R 420 horsepower reciprocating
- Damage: Minor damage
- Flight: Personal, Part 91
- Registered owner: Sunset Flying Service LLC
- Airworthiness certificate: Standard, Normal
- Departed: RRT, Warroad, MN
- Destination: Same as departure
- Equipment: Unknown

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 74; injuries: none; private, commercial; airplane ratings: single-engine sea, single-engine land; medical: unknown, unknown; seat: left; restraint: lap only; flight hours: 5,000 total, 3,000 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Lowest ceiling: none

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 20210522009939A](https://openairdocs.org/incident/20210522009939A), May 22, 2021: Dehavilland DHC-2 MK.I, Oak Island, MN, Minor damage. 2021-05-22 N218RD, DHC-2 beaver, on amphibious edo floats, departed warroad MN (krrt) for a 37 mile flight to Sunset Lodge on Oak Island in the northwest angle…

## Docket (4 files)

The files NTSB released with the investigation on July 22, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=103181. 26.2 MB in all.

- NTSB request for pilot/operator report (item 1, PDF, 3 pages, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12458898&FileExtension=pdf&FileName=6120%20request%201_Redacted-Rel.pdf
- Excerpt of sheriff report (item 2, PDF, 3 pages, 17.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12458571&FileExtension=pdf&FileName=Excerpt%20of%20Sheriff%20Report_Redacted-Rel.pdf
- Photo array (item 3, PDF, 2 pages, 150 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12457990&FileExtension=pdf&FileName=Photo%20Array-Rel.pdf
- Video file of hydraulic leak (provided by pilot/owner) (item 4, MOV, 7.7 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=12458535&FileExtension=MOV&FileName=IMG_3836-Rel.MOV

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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