CEN21LA244

NTSB accident investigation · Dehavilland DHC-2 MK.I · Oak Island, MN · May 22, 2021

Accident · Serious injuriesClass 3 · LimitedFinal report
Date
May 22, 2021, 18:30 local (23:30 UTC)
Place
Oak Island, MN
Injuries
1 serious, 2 uninjured
Damage
Minor damage
Phase of flight
Landing
Aircraft
N218RDDehavilland DHC-2 MK.I
Defining event
Landing: Sys/Comp malf/fail (non-power)
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Central Region
Parties
FAA
FAA report
20210522009939A
Case key
103181

From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.

On this page

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 · 3

NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.

Not determinedNot determined › Not determined · Unknown/Not determinedDehavilland DHC-2 MK.I: 1 caseAll aircraft: 2,247 casesProbable cause

Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.

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
Reported as
Dehavilland DHC-2 MK.I
Category
Airplane
Serial number
50
Built
1949
Engine
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

Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.

Flight crew

As NTSB recorded them. NTSB leaves out names.

Role
Pilot
Age
74
Injuries
None
Certificates
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

Docket · 4

The files NTSB released with the investigation on July 22, 2022, on NTSB’s docket system: statements, records, photos and specialists’ reports. 26.2 MB in all.

FAA reports on this event · 1

The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.