LAX96LA258

NTSB accident investigation · Davis Challenger I CW · Paso Robles, CA · July 2, 1996

Accident · FatalLimited investigationFinal report
Date
July 2, 1996, 08:55 local (15:55 UTC)
Place
Paso Robles, CA
Injuries
1 fatal
Damage
Destroyed
Phase of flight
Initial climb
Aircraft
N75489Davis Challenger I CW
Weather
Visual (VMC) · Day
Status
Completed · report February 2, 1998
Report
Approved by Office Director
FAA report
19960702015779A
Case key
29494

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 owner/builder/pilot's impairment of judgment and performance due to drugs which led to his improper handling of the airplane and failure to maintain an adequate airspeed margin above stall speed, resulting in an inadvertent stall/spin. A factor which contributed to the accident was the owner/builder/pilot's use of an inadequate adhesive material in the construction of the airplane which resulted in a portion of the wing root surface skin to debond, separate, and impact a propeller blade, which also separated.

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/malfunctionTakeoff - initial climb
Wing,skin - debondedFactor
Material inadequate,improperOwner/builderFactor
Wing,skin - separation
Propeller failure/malfunctionTakeoff - initial climb
Propeller system/accessories,blade - foreign object damageFactor
Propeller system/accessories,blade - separation
Loss of control - in flightTakeoff - initial climb
Aircraft handling - improperPilot in commandCause
Impairment(drugs)Pilot in commandCause
Airspeed(vso) - not maintainedPilot in commandCause
Stall/spin - inadvertentPilot in command
In flight collision with terrain/waterDescent - uncontrolled

Analysis

The accident occurred during the pilot's maiden flight of the homebuilt following completion of construction the preceding week. According to a witness, the pilot took off and climbed 100 feet above the runway surface. During the climb, an airframe component separated from the wing and contacted the wood pusher propeller. A blade separated and all engine power was lost. The airplane then porpoised several times, turned 90 degrees from its runway heading, and collided with the ground in a 45-degree nose-down pitch attitude. A bent plastic (Lexan) strip was found about 300 feet downwind of the main wreckage and in close proximity to the separated propeller blade. The strip had been attached to the center section of the wing, forward of the engine, with Velcro self-adhesive tape. The adhesive remained attached to the wing, but it failed to adhere to the Lexan. In November, 1994, the FAA denied the pilot's last application for an aviation medical certificate because of his cardiovascular condition. Toxicology tests on the pilot revealed the presence of tranquilizers chlordiazepoxide (Librium) and diazepam (Valium), and the antidepressant amitriptyline (Elavil). Use of these drugs could adversely influence the pilot's mental processes, reaction time, and ability to control the airplane.

Factual narrative

History of flight

On July 2, 1996, at 0855 hours Pacific daylight time, a Davis Challenger I CW, N75489, owned and operated by the pilot, crashed during its maiden flight at the Paso Robles Municipal Airport, Paso Robles, California. The experimental amateur built airplane was destroyed, and the private pilot was fatally injured during the personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The flight was originating at the time of the accident.

A witness reported observing the airplane's takeoff and crash. The witness stated that the takeoff roll appeared normal, but seconds after the airplane lifted off the runway, around 100 feet above ground level, a light colored small component separated from the upper surface of a wing and contacted the pusher wood propeller. One blade separated, the engine stopped operating, and the airplane porpoised up and down several times. Then, the airplane turned 90 degrees from its runway heading, pitched nose down, and impacted the ground while in a 45-degree nose down attitude.

The Federal Aviation Administration (FAA) coordinator performed an on-scene examination of the crash site. According to the FAA, a bent plastic (Lexan) strip was located about 300 feet downwind of the main wreckage and in close proximity to the separated propeller blade. An examination of the wreckage revealed that the strip had been attached to the upper surface of the wing's center section with Velcro self-adhesive tape. The adhesive material had failed to secure the strip to the wing.

The Lexan strip was rectangular in shape, and was designed to cover a gap in the fuselage forward of the engine assembly. The pilot purchased the homebuilt kit in November, 1995. Construction was completed the week preceding the accident flight. The pilot reportedly had performed taxi tests for about 1.5 hours preceding his first attempted takeoff.

Personnel information

According to the FAA, when the pilot last applied for an aviation medical certificate on November 29, 1994, he reported that his total flying experience was about 185 hours, and he had flown 5 hours during the preceding 6-month period. The FAA did not issue the pilot the requested certificate because of his cardiovascular condition.

Medical and pathological information

On July 5, 1996, an autopsy on the pilot was performed by the San Luis Obispo County Coroner's Office, San Luis Obispo, California.

The FAA performed toxicology tests on specimens from the pilot, and found evidence of drugs including chlordiazepoxide, diazepam, amitriptyline, atenolol and diltiazem in blood and liver fluid. No ethanol was detected.

According to the manager of the FAA's toxicology and accident research laboratory, these drugs may be prescribed for conditions including depression and hypertension. In brief, use of these drugs could adversely influence the pilot's mental processes, reaction time, and ability to control the airplane.

Aircraft

Registration
N75489
Reported as
Davis Challenger I CW (CHALLENGER)
Category
Airplane, amateur-built
Serial number
119CW0594
Engine
Rotax 503, reciprocating
Damage
Destroyed
Flight
Personal · Part 91
Registered owner
Robert S. Davis
Airworthiness certificate
Special, Experimental (Special)
Last inspection
Annual · June 28, 1996 · 0 hours before
Departed
PRB
Airport
PRB · Paso Robles, runway 19, 6,009 × 150 ft, asphalt

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
74
Certificate
Private
Airplane ratings
Single-engine land
Seat
Front
Toxicology
Performed
Flight hours
185 total · 4 in the last 90 days

Weather

Conditions
Visual (VMC) · Day
Wind
Calm
Visibility
10 statute miles
Lowest ceiling
None
Temperature
75 °F

FAA reports on this event · 1

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