CEN18LA200

NTSB accident investigation · Irlbeck Thomas H RV 8 · Somerset, WI · May 29, 2018

Accident · No injuriesClass 3 · LimitedFinal report
Date
May 28, 2018, 19:45 local (May 29, 2018, 00:45 UTC)
Place
Somerset, WI
Injuries
2 uninjured
Damage
Substantial damage
Phase of flight
Enroute
Aircraft
N214FFIrlbeck Thomas H RV 8
Defining event
Enroute: Loss of engine power (total)
Weather
Visual (VMC) · Night
Status
Completed
Report
Approved by Office Director
Investigation class
Class 3
NTSB office
Central Region
Parties
FAA
FAA report
20180528006099A
Case key
97344

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 damaged and disconnected electronic ignition wires from both the main and backup batteries, which resulted in a forced landing.

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.

Engine (reciprocating)Aircraft › Aircraft power plant · FailureIrlbeck Thomas H RV-8: 1 caseAll aircraft: 497 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 reported that, while in cruise flight in the experimental, amateur-built airplane, the radio and GPS lights flickered, followed by a total loss of engine power. He attempted to troubleshoot the loss of power and then conducted a forced landing to a field, during which the airplane impacted a fence; the wings were substantially damaged. Examination revealed that the wire connection from the main battery to the engine's electronic ignition had melted just above the terminal attachment. Although the airplane was equipped with a backup battery, the connection from the backup battery to the ignition was disconnected, which pre and the wire connection from the electronic ignition to the backup battery was not connected to the battery terminal. While the melted wire that connected the main battery to the electronic ignition would still have allowed power to the electronic ignition from the backup battery, the lack of connection to the backup battery provided no power to the electronic ignition and resulted in the total loss of engine power.

Factual narrative

On May 28, 2018, about 2015 central standard time, an experimental, amateur-built RV-8, N214FF, was substantially damaged when it was involved in an accident near Somerset, Wisconsin. The private pilot and passenger received minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot stated that, about 10 miles from the destination airport, the sky was dark, with lightning and increasing wind conditions, and he decided to divert to his private grass runway. Shortly thereafter, the airplane's radio and GPS unit started to flicker and then went completely dark, followed by a total loss of engine power. The pilot attempted to troubleshoot the loss of engine power and stated that the mixture was at full rich and the electric boost pump was on. He noticed that the switch light on the electric boost pump was very dim and there was no response when he flipped the switch. He tried to “pump” the throttle and changed the fuel selector from the left to right tank, but engine power was not restored. The pilot stated that he was losing airspeed and altitude, and he selected a field to conduct a forced landing, during which the airplane's right main landing gear impacted a fence, resulting in substantial damage to the wings. A Federal Aviation Administration (FAA) inspector examined the airplane after the accident and reported that the main battery was a homemade, gel-cell battery with a bundle of small, melted wires attached to the positive battery post. One of the wires in this melted bundle was connected to the engine's electronic ignition system. A backup battery was mounted to the engine firewall with a spade connector wire lead, which was disconnected. This wire connected the electronic ignition to the backup battery. The back-up battery was tested with a voltmeter and was fully charged.

Aircraft

Registration
N214FF
Reported as
Irlbeck Thomas H RV 8 (UNDESIGNAT)
Category
Airplane, amateur-built
Serial number
80687
Built
1988
Airframe hours
2,069
Engine
Lycoming O-360-B1A, 180 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Special, Experimental light sport (Special); Special, Experimental (Special)
Last inspection
Condition · September 20, 2017
Departed
21D · Lake Elmo, MN
Destination
OEO · Osceola, WI
Equipment
Auto-pilot, Electronic primary flight display, Onboard weather

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
67
Injuries
Minor
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, With waivers/limitations
Last flight review
September 12, 2017
Seat
Front
Restraint
5-point
Flight hours
935 total · 80 in this make and model · 935 as pilot in command · 8 in the last 90 days · 8 in the last 30 days

Weather

Conditions
Visual (VMC) · Night
Wind
120° at 5 knots
Visibility
10 statute miles
Temperature
73 °F, dew point 68 °F
Altimeter
30.00 inHg
Observed at
KOEO, 10 nm away

Docket · 3

The files NTSB released with the investigation on January 26, 2021, on NTSB’s docket system: statements, records, photos and specialists’ reports. 968 KB 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.