CEN23LA338

NTSB accident investigation · Rans S-6ES · Ozark, AR · July 29, 2023

Accident · Minor injuriesClass 4 · LimitedFinal report
Date
July 29, 2023, 18:00 local (23:00 UTC)
Place
Ozark, AR
Injuries
2 minor
Damage
Destroyed
Phase of flight
Initial climb
Aircraft
N123TGRans S-6ES
Defining event
Initial climb: Loss of engine power (total)
Weather
Visual (VMC) · Day
Status
Completed
Report
Approved by Office Director
Investigation class
Class 4 - Basic report with no Prelim publish
NTSB office
Central Region
Parties
Federal Aviation Administration
FAA report
20230729012869A
Case key
192753

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

Oil starvation of the propeller speed reduction unit which resulted in a total loss of engine power.

Findings · 1

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.

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 stated that on his second flight in the airplane, he completed some basic maneuvers without incident and returned to the airport. Shortly after, he and a passenger boarded for a local flight. The pilot completed an engine run up with no anomalies noted, and then departed from the grass runway. About 70 ft above ground level he felt a vibration and was unable to maintain altitude. The engine RPM and oil pressure decreased as the airspeed slowed. The airplane collided with trees and then impacted the ground. The pilot and passenger egressed without incident, then the airplane burst into flames. The passenger recorded a video of the entire accident flight. The video revealed that during the initial climb, the engine RPM and sound appeared to gradually decrease. The airplane did not continue to climb, and the engine RPM continued to decrease. The airplane collided with a tree and then impacted the ground. A postaccident photo from the pilot showed the airplane was mostly consumed by the fire. The pilot provided a summary of his postaccident engine examination, which revealed that the oil supply line to the propeller speed reduction unit was completely clogged with an unknown gray material. Also, the gear reduction drive was seized, lacked oil, and the bearings were covered in a dry, rusty powder. It is likely that the loss of engine power was due to oil starvation of the propeller speed reduction unit.

Aircraft

Registration
N123TG
Reported as
Rans S-6ES
Category
Airplane, amateur-built
Serial number
0291162
Built
1991
Airframe hours
1,386
Engine
Ram Performance Subaru E81, 110 horsepower, reciprocating
Damage
Destroyed
Fire
On-Ground
Flight
Personal · Part 91
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Annual · May 25, 2023
Airport
2AR1 · Etna Airport, runway 9, 2,130 × 100 ft, grass/turf
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
59
Injuries
Minor
Certificate
Private
Airplane ratings
Single-engine land
Medical
BasicMed
Last flight review
May 5, 2023
Seat
Left
Restraint
3-point
Flight hours
142 total · 1 in this make and model · 38 as pilot in command · 9 in the last 90 days · 1 in the last 30 days · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
10 statute miles
Lowest ceiling
None
Temperature
99 °F, dew point 72 °F
Altimeter
30.01 inHg
Observed at
KFSM, 26 nm away
METAR
KFSM 292253Z 00000KT 10SM CLR 37/22 A3001 RMK AO2 SLP156 T03670217

Docket · 4

The files NTSB released with the investigation on September 28, 2023, on NTSB’s docket system: statements, records, photos and specialists’ reports. 3.5 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.