FTW96FA085

NTSB accident investigation · Semple Smyth Sidewinder · Oklahoma City, OK · January 8, 1996

Accident · FatalField investigationFinal report
Date
January 8, 1996, 16:57 local (22:57 UTC)
Place
Oklahoma City, OK
Injuries
1 fatal
Damage
Destroyed
Phase of flight
Enroute
Aircraft
N86SSemple Smyth Sidewinder
Weather
Visual (VMC) · Day
Status
Completed · report September 3, 1996
Report
Approved by Office Director
FAA report
19960108012019A
Case key
19616

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

The pilot's improper positioning of the fuel selector, which resulted in fuel starvation and loss of engine power, and his failure to maintain sufficient airspeed while coping with the emergency, which resulted in and inadvertent stall and subsequent spin. Factors relating to the accident were: the pilot's lack of experience in type of airplane, and habit interference with respect to use of the fuel selector.

Sequence of events

NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.

Loss of engine power(total) - nonmechanicalClimb - to cruise
Fluid,fuel - starvationCause
Fuel tank selector position - improperPilot in commandCause
Habit interferencePilot in commandFactor
Loss of control - in flightEmergency descent/landing
Airspeed - not maintainedPilot in commandCause
Stall/spin - inadvertentPilot in commandCause
Lack of total experience in type of aircraftPilot in commandFactor
In flight collision with terrain/waterDescent - uncontrolled

Analysis

The pilot had just purchased the airplane and was planning to return to his home in Tulsa, Oklahoma. He and the seller flew the airplane on an 'orientation ride' for 'approximately 10 minutes' before the pilot departed. According to the seller, the pilot had considerable experience in a similar airplane, but the fuel selector handles in the two airplanes were configured in an opposite manner. The accident airplane was observed to depart from runway 17 and turn east. At approximately a quarter of a mile from the airpark and at approximately 500 feet AGL, the engine began to 'sputter.' About 8 seconds later, the engine 'quit.' The airplane continued east and was observed to make a gentle bank to the right and then to the left, but 'the nose was never lowered to establish a glide.' The airplane was observed to stall and spin to the left, rotating about 2 turns before impacting the ground. Postimpact examination of the fuel selector handle and valve revealed they were in the 'off' position.

Factual narrative

History of flight

On January 8, 1996, at 1657 central standard time, a Smyth Sidewinder, N86S, was destroyed upon impact with terrain following a loss of control near Oklahoma City, Oklahoma. The private pilot was fatally injured. The aircraft was being operated by the owner under Title 14 CFR Part 91. The flight originated from the Sundance Airpark located near Oklahoma City, Oklahoma, at approximately 1655. Visual meteorological conditions prevailed for the cross country flight to Tulsa, Oklahoma, and a flight plan was not filed.

According to a witness, the pilot agreed to purchase the airplane from him approximately 1 hour and 15 minutes before the accident. The witness and the pilot flew the accident aircraft locally for an "orientation ride" for "approximately 10 minutes." After landing, the witness put an additional 11 gallons of fuel in the aircraft, in preparation for the pilot's trip home to Tulsa, Oklahoma. The witness further stated that he suggested to the pilot that he takeoff with the fuel selector on the right tank because, of the 3 fuel tanks in the aircraft, it had the most fuel in it. The witness stated that the last time he looked in the cockpit, the fuel selector was on the right tank.

According to witnesses, the airplane departed from runway 17 and was observed turning east. At approximately a quarter of a mile from the airpark, when the airplane was approximately 500 feet AGL, the engine began to "sputter." Approximately 8 seconds later, the engine "quit." The airplane continued east and was observed by one witness to make a gentle bank to the right and then to the left, but "the nose was never lowered to establish a glide." The witness further stated that the aircraft "stalled and spun to the left two turns before hitting the ground."

Personnel information

The pilot's previous experience in an aircraft with a header fuel tank was in an experimental home built aircraft called a Thorp, which his father had built. The pilot's father reported to the investigator-in-charge that he and his son had had conversations about why it was safer to takeoff in an aircraft with the fuel coming from a gravity feed fuel tank as opposed to one which required an electric driven fuel boost pump. The Thorp's main fuel tank was a header tank, which because of its location, didn't require an electric boost pump for takeoff. The pilot had approximately 300 to 400 hours flight experience in the Thorp.

The witness that sold the accident aircraft to the pilot is currently the owner of the above mentioned Thorp. He stated that in the Thorp, the long end of the fuel selector handle points at the chosen tank, but in the Sidewinder, the short end of the fuel selector handle points at the chosen tank.

Aircraft information

The accident aircraft had 3 fuel tanks, a 15 gallon left tank, a 10 gallon header tank, and a 15 gallon right tank. The aircraft is equipped with an engine driven fuel pump and electric driven fuel boost pump. According to the manufacture, a takeoff can be performed on any of the aircraft's 3 tanks.

Wreckage and impact information

The airplane impacted the ground on a measured heading of 245 degrees, bounced once, and came to rest on a measured heading of 170 degrees, in an open field approximately 1/4 miles east of Sundance Airpark. The leading edges of both wings were compressed aft. The wings remained attached to the fuselage and their respective fuel tanks were compromised. The cabin section aft of the instrument panel and the empennage were intact although the right elevator was broken off. The engine, firewall, and the forward portion of the cabin were broken off. The header fuel tank was compromised. The wooden propeller blades were broken off but the propeller hub remained attached to the crankshaft.

The fuel selector valve handle was found in the "off" position. The fuel selector valve was visually verified to be in the "off" position.

Medical and pathological information

An autopsy and toxicological tests were ordered and performed. The autopsy was performed by the Office of the Chief Medical Examiner at Oklahoma City, Oklahoma, on January 9, 1996. Toxicological tests were negative.

Additional data

The airplane was released to the owner's representative.

Aircraft

Registration
N86S
Reported as
Semple Smyth Sidewinder (SMYTH SIDE)
Category
Airplane, amateur-built
Serial number
212090
Airframe hours
500
Engine
Lycoming O-320-B2B, 160 horsepower, reciprocating
Damage
Destroyed
Flight
Personal · Part 91
Registered owner
Gary W. Holt
Airworthiness certificate
Special, Experimental (Special)
Departed
HSD
Destination
TUL · Tulsa, OK

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
44
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, Valid Medical--no waivers/lim.
Seat
Left
Toxicology
Performed
Flight hours
3,000 total

Weather

Conditions
Visual (VMC) · Day
Wind
200° at 18 knots, gusting 24
Visibility
10 statute miles
Lowest ceiling
None
Temperature
48 °F, dew point 25 °F
Altimeter
30.00 inHg
Observed at
OKC, 17 nm away

FAA reports on this event · 1

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