CEN21LA092

NTSB accident investigation · Sonex Tailwheel · Burleson, TX · December 19, 2020

Accident · FatalClass 3 · LimitedFinal report
Date
December 19, 2020, 14:30 local (20:30 UTC)
Place
Burleson, TX · 76028
Injuries
1 fatal
Damage
Substantial damage
Phase of flight
Initial climb
Aircraft
N935EKSonex Tailwheel
Defining event
Initial climb: 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
Federal Aviation Administration
FAA report
20201219020619A
Case key
102435

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 engine seizure. Contributing to the accident was the pilot decision not to orbit the airport, as originally planned.

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 · MalfunctionKirkpatrick Earl L SONEX - TAILWHEEL: 1 caseAll aircraft: 497 casesProbable cause
Fluids: oilAircraft › Fluids/misc hardware · Unknown/Not determinedKirkpatrick Earl L SONEX - TAILWHEEL: 1 caseAll aircraft: 174 cases

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 and builder of the airplane was conducting the airplane’s first flight. The pilot contacted the tower controller and requested to orbit the airport for 30 minutes at 3,500 ft. Shortly after departure, the pilot reported that he was unable to climb and needed to return to the airport. The pilot reported that he had a “sick engine,” and he was “just trying to make the field.” The controller reported to the pilot that smoke appeared to be coming from the engine. Automatic Dependent Surveillance–Broadcast (ADS-B) data revealed the airplane departed from the airport, turned, and flew south for about 2 miles before it turned north back to the airport. During the subsequent forced landing, the airplane impacted powerlines and terrain and came to rest inverted about 1 mile south of the airport. During the engine examination oil was present on the dipstick. The oil filter was cut open and fine metal pieces/powder were observed on the filter element, and small metal pieces were observed in the engine’s oil filter port. The engine was seized and could not be rotated by hand. The engine was not dissembled further, and the source of the metal filings was not determined. The loss of engine power was attributed to the seizure of the engine; however, the reason for the engine seizure could not be determined. Investigators were unable to determine why the pilot did not stay over the airport and orbit as originally requested.

Factual narrative

On December 19, 2020, about 1430 central standard time, a Sonex light sport airplane, N935EK, was substantially damaged when it was involved in an accident near Burleson, Texas. The pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations 91 personal flight. A witness reported that the airplane had been built as a kit and this was the airplane’s first flight. A review of air traffic control information revealed that the pilot contacted the Spinks Airport (FWS) controller and requested to orbit the airport for 30 minutes at 3,500 ft. Shortly after departure, the controller asked if the pilot needed any assistance. The pilot reported that he was unable to climb and needed to return to the airport. The controller cleared the pilot direct to the airport and to land on runway 35. The pilot reported that he had a “sick engine,” and he was “just trying to make the field.” The controller reported to the pilot that smoke appeared to be coming from the engine. A review of Automatic Dependent Surveillance–Broadcast (ADS-B) data revealed the airplane departed from FWS, turned, and flew south for about 2 miles before it turned north back to the airport. (see Figure 1.) During the forced landing, the airplane impacted powerlines and terrain and came to rest inverted near a business about 1 mile south of the airport. Figure 1: Airplane’s Flight Track An engine examination revealed a light film of oil on the underside of the airplane’s fuselage. No evidence of an inflight fire was observed. A visual inspection of the engine did not reveal any obvious discrepancies in the engine or an avenue for engine oil to escape. An attempt to rotate the engine by turning the propeller by hand revealed that the engine was seized. The engine was equipped with a remote oil filter mounted on the firewall. Two oil lines from the oil filter adapter ran to the front of the engine where the engine’s oil pump was located; one line ran from the “inlet” side of the oil filter adapter to one side the oil pump. On the other side of the pump, an oil line ran to the “outlet” side of the oil filter adapter. The oil filter was removed and cut open; small, fine metal pieces/powder were in the oil and on the filter element. Small metal pieces were seen when looking into the engine’s oil filter port and oil was present on the dip stick. The engine was not dissembled further and the source of the metal filings was not determined. The airplane was equipped with a Dynon EMS D10 engine monitoring system. Review of recorded data did not reveal any information that could be correlated to the accident flight. The airplane’s hour meter showed 213.9 hours which was not consistent with the accident flight being the first flight for the airplane.

Aircraft

Registration
N935EK
Reported as
Sonex Tailwheel
Category
Airplane, amateur-built
Serial number
1617
Built
2019
Engine
AeroVee, 80 horsepower, reciprocating
Damage
Substantial damage
Flight
Personal · Part 91
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Condition · September 18, 2020
Airport
FWS · Fort Worth Spinks Airport
Equipment
ADS-B, Electronic primary flight display

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
85
Injuries
Fatal
Certificate
Commercial
Airplane ratings
Single-engine land
Instrument ratings
Airplane
Medical
Class 3, With waivers/limitations
Seat
Left
Restraint
4-point
Toxicology
Performed
Flight hours
2,195 total

Weather

Conditions
Visual (VMC) · Day
Wind
300° at 9 knots
Visibility
10 statute miles
Temperature
57 °F, dew point 46 °F
Altimeter
30.08 inHg
Observed at
KFWS, 1 nm away

Docket · 8

The files NTSB released with the investigation on April 6, 2021, on NTSB’s docket system: statements, records, photos and specialists’ reports. 40.2 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.