CEN21LA343

NTSB accident investigation · Stinson JR. SR · Ripon, WI · July 29, 2021

Accident · Minor injuriesClass 3 · LimitedFinal report
Date
July 29, 2021, 12:30 local (17:30 UTC)
Place
Ripon, WI
Injuries
1 minor, 3 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N81YStinson JR. SR
Defining event
Enroute: Loss of engine power (total)
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Central Region
Parties
FAA FSDO
FAA report
20210729012099A
Case key
103589

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

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Probable cause

A total loss of engine power due to fuel starvation.

Findings · 2

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.

Fluids: fuelAircraft › Fluids/misc hardware · Fluid levelStinson JR. SR: 1 caseAll aircraft: 1,695 casesProbable cause
AircraftAircraft › Aircraft power plant · FailureStinson JR. SR: 1 caseAll aircraft: 151 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

The pilot was in-bound to the destination airport when the engine lost total power. The pilot conducted a forced landing to a muddy field where the airplane nosed over and came to rest inverted. Examination of the airplane revealed substantial damage to the empennage. One fuel tank was empty and there was fuel staining on the soil. The pilot reported that the airplane should have had about 15 to 20 gallons of fuel remaining at the time of the accident. In a subsequent conversation, the pilot reported that the airplane had an “odd fuel system” and if the fuel level was low, the engine could experience fuel starvation due to decreased fuel pressure, to which he attributed the loss of engine power on the accident flight.

Factual narrative

On July 29, 2021, about 1230 central daylight time, a Stinson JR SR airplane, N81Y, was substantially damaged when it was involved in an accident near Ripon, Wisconsin. The pilot received minor injuries and the three passengers were not injured. The airplane was operated as a Title 14 Code of Federal Regulations 91 personal flight. The airplane was in-bound to the destination airport via a visual flight rules arrival procedure when the engine lost total power. The pilot conducted a forced landing to a muddy field where the airplane nosed over and came to rest inverted. The responding Federal Aviation Administration (FAA) inspector noted substantial damage to the empennage. The inspector also noted that the one fuel tank was empty and there was fuel staining on the soil. The pilot reported that the airplane should have had about 15 to 20 gallons of fuel remaining. He added that the carburetor was recently overhauled and that there might have been something wrong with the carburetor. In a subsequent conversation, the pilot reported that he believed that nothing was wrong with the carburetor, but the airplane had an “odd fuel system” and if the fuel level was low, the engine could experience fuel starvation due to decreased fuel pressure, to which he attributed the loss of engine power.

Aircraft

Registration
N81Y
Reported as
Stinson JR. SR
Category
Airplane
Serial number
8729
Built
1933
Airframe hours
187
Engine
Lycoming 680, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Standard, Normal
Last inspection
Annual · May 10, 2021
Departed
Dekalb, IL
Destination
OSH · Oshkosh, WI
Equipment
None

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
40
Injuries
Minor
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, Without waivers/limitations
Seat
Left

Weather

Conditions
Visual (VMC) · Day
Wind
90° at 8 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
81 °F, dew point 72 °F
Altimeter
29.94 inHg
Observed at
KOSH
METAR
KOSH 291653Z 09008KT 10SM SCT031 27/22 A2994 RMK AO2 SLP125 T02720217

Docket · 3

The files NTSB released with the investigation on November 30, 2021, on NTSB’s docket system: statements, records, photos and specialists’ reports. 2.3 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.