MIA94LA105

NTSB accident investigation · Wallace Thorp T-18 · Boynton Beach, FL · March 27, 1994

Accident · FatalLimited investigationFinal report
Date
March 27, 1994, 07:15 local (12:15 UTC)
Place
Boynton Beach, FL
Injuries
1 fatal
Damage
Destroyed
Phase of flight
Maneuvering
Aircraft
N215CKWallace Thorp T-18
Weather
Visual (VMC) · Day
Status
Completed · report November 18, 1994
Report
Approved by Office Director
FAA report
19940327007829A
Case key
37515

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 in command's exceeding the designed stress limits of the aircraft resulting in overload failure of the left wing outboard attach fitting. This resulted in inflight separation of the outboard left wing, and subsequent inflight collision with the terrain during an uncontrolled descent.

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.

Airframe/component/system failure/malfunctionManeuvering
Design stress limits of aircraft - exceededPilot in commandCause
Wing,wing attachment fitting - overload
Wing,wing attachment fitting - failure,total
Wing - separation
In flight collision with terrain/waterDescent - uncontrolled
Aircraft control - not possiblePilot in command
Terrain condition - water

Analysis

Witnesses heard the sound of the aircraft's engine increase and decrease several times. They then heard a 'loud pop' or 'explosion' and observed the aircraft descending in a spin with part of a wing missing. The outboard left wing was found 1/4 mile from the main wreckage along with the left aileron and debris from the canopy and cabin of the aircraft. Examination of the left wing indicated the outboard wing section separated in a downward direction due to overstress at the point it attaches to the inboard section. All other separations of structural components and flight control surfaces had separation features typical of overstress. Examination of the engine showed no evidence of precrash failure or malfunction.

Factual narrative

History of flight

On March 27, 1994, about 0715 eastern standard time, a Wallace Thorp T-18, N215CK, registered to Charles F. Kenny, crashed while maneuvering near Boynton Beach, Florida, while on a 14 CFR Part 91 personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft was destroyed and the private-rated pilot received fatal injuries. The flight originated at Lantana, Florida, on March 27, 1994, about 0700.

Witnesses reported hearing engine sounds from the aircraft which increased and decreased in power output several times. They did not visually observe the aircraft. They then heard a "loud pop" or "explosion." They looked toward the noise and observed the aircraft descending in a spin with part of a wing missing.

Personnel information

After the accident involving N215CK, the pilot's family was unable to locate a pilot logbook. Additional pilot information is contained in this report under Pilot Information.

Aircraft information

The pilot's son stated after the accident that he had custody of the maintenance records for N215CK. The son did not submit these records for examination as requested by NTSB on several occasions. Additional information on the aircraft is contained in this report under Aircraft Information.

Meteorological information

Visual meteorological conditions prevailed at the time of the accident. Additional meteorological information is contained in this report under Weather Information.

Wreckage and impact information

The aircraft crashed in a swamp in the Loxahatchee Wildlife Refuge, near Boynton Beach, Florida. The aircraft's outboard left wing was located about 1/4 mile north of the main wreckage of the aircraft. The left aileron, debris from the canopy structure, and debris from the cabin area of the aircraft were located between the left wing and the main wreckage. All other components of the aircraft, except for the right horizontal stabilizer and elevator and the vertical stabilizer, were located on or around the main wreckage of the aircraft. The right horizontal stabilizer, right elevator, and vertical stabilizer were not located after the accident. No parachute was found in the wreckage or on the pilot.

Examination of the left wing indicated the outer wing section from the point the flap and aileron meet separated downward. The complete bottom portion of main spar fitting pulled loose from were it attaches to the bottom of the outboard wing section. The top portion of the main spar fitting separated within the fitting. The fitting fracture surface was typical of overstress separation. The rear spar separated when the sheet metal tore loose between the inner and outer wing sections. There were no impact marks on the outer wing panel.

The left aileron separated from the outboard left wing panel and was found near the outer left wing panel. The aileron had separated when the outboard hinge pulled loose from the wing panel and the sheet metal to which the inboard aileron hinge was attached pulled loose from the rear wing spar. The aileron control rod separated with fracture features typical of overstress.

Examination of the separation points of the left and right horizontal stabilizers and the vertical stabilizer indicated fracture features typical of overstress separation. Examination of the flight control systems indicated that all separation of flight control surfaces or separations within the flight control linkages were typical of overstress separation.

Examination of the engine from N215CK indicated the engine rotated normally and continuity was established within the crankshaft, camshaft, valve train, and accessory drives. Each cylinder produced normal compression and each spark plug had coloring typical of a normally operating engine. Each magneto operated normally. The carburetor float operated normally and all jets were free of obstructions. The propeller was in the low pitch or high rpm blade angle. The engine-driven fuel pump operated normally and automotive fuel was found in the carburetor and fuel pump.

Medical and pathological information

Post-mortem examination of the pilot was performed by Dr. Stephen J. Nelson, M.D., Associate Medical Examiner, Palm Beach County, Florida. The cause of death was attributed to multiple blunt force traumatic injuries. Post-mortem toxicology testing on specimens obtained from the pilot was performed by F. Thomas Carroll, Chief Toxicologist, Palm Beach County Sheriff's Office and by Barry Levine, PhD., Chief Forensic Toxicology Laboratory, Armed Forces Institute of Pathology, Washington, D.C. The tests were negative for ethanol, basic, acidic, and neutral drugs. For additional medical and pathological information see Supplement K and the toxicology reports attached to this report.

Additional information

The aircraft wreckage was released on March 27, 1994 to a refuge officer at the Loxahatchee Wildlife Refuge. On April 6, 1994, components retained by NTSB for examination were released to Lilian Brochard, Murphy's Towing, West Palm Beach, Florida.

Aircraft

Registration
N215CK
Reported as
Wallace Thorp T-18 (THORP T-1)
Category
Airplane, amateur-built
Serial number
JSW310
Engine
Lycoming O-360-F1A6, 180 horsepower, reciprocating
Damage
Destroyed
Flight
Personal · Part 91
Registered owner
Charles F. Kenny
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Annual · September 13, 1993 · 26 hours before
Departed
LNA · Lantana, FL

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
69
Certificate
Private
Airplane ratings
Single-engine land
Medical
Class 3, Valid Medical--w/ waivers/lim
Seat
Left
Toxicology
Performed
Flight hours
2,100 total · 1 in the last 24 hours

Weather

Conditions
Visual (VMC) · Day
Wind
140° at 17 knots
Visibility
10 statute miles
Lowest ceiling
None
Temperature
79 °F, dew point 70 °F
Altimeter
29.00 inHg
Observed at
PBI, 13 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.