NTSB Factual Report

HISTORY OF FLIGHT

On May 12, 1998, at 1505 central daylight time, a Beech 76 twin engine airplane, N6701C, was destroyed upon impact with terrain following a loss of control while maneuvering during a check flight (practical test) near Frisco, Texas. The instrument rated commercial pilot was seriously injured and the airline transport rated pilot, who was functioning as a pilot examiner, was fatally injured. The airplane was owned and operated by Ari Ben Aviator Inc., of Addison, Texas. Visual meteorological conditions prevailed for the Title 14 CFR Part 91 check flight for which a flight plan was not filed. The local flight originated from the Addison Airport at 1415.

The operator reported that the local flight had been scheduled for completion of the practical test for a commercial rating. The FAA designated pilot examiner (DPE) was seated in the right seat to administer the check flight. The operator further stated that the pilot had been provided 5 additional hours of dual instruction after the pilot failed a previous practical test due to unsatisfactory performance of a minimum control velocity (Vmca) maneuver with the same DPE.

An eyewitness who was travelling on a farm road (FM 720) observed the blue and white twin engine airplane conducting touch and go takeoffs and landings on runway 17 at the North Dallas Jetport (DDJ), near Frisco, Texas. Another witness observed the airplane climbing in what appeared to be "a sharp right turn towards the north." When the witness looked again, about 10 seconds later, he saw "thick smoke and flames."

The operator stated that for the last 2 years, company policy prohibited touch and go landings in any of their nine twin engine airplanes, and only full stop landings were to be performed during any phase of training or check flights.

PERSONNEL INFORMATION

The 39 year old instrument rated commercial pilot received his commercial pilot certificate on October 16, 1990, and become a certificated flight instructor on May 21, 1991. At the time of his last FAA medical examination on February 17, 1998, the pilot had accumulated a total of 1,019 flight hours. The operator's training records reflected that the pilot had accumulated a total of 1,047 hours, of which 29 hours were in the accident make and model. He had logged 11 hours in the same type of aircraft in the 30 days preceding the accident.

The pilot remained hospitalized for over 90 days. The NTSB investigator-in-charge (IIC) arranged for and conducted a telephone interview with the pilot. During the brief interview, the pilot reported to the NTSB IIC that he had "no recollection of the accident or any portion of the flight."

The 67 year old airline transport rated pilot acting as an FAA designated pilot examiner, had accumulated a total of 8,000 hours of flight time, of which approximately 1,000 hours were in the Beech model 76 airplane. FAA records revealed that his last second class FAA medical examination was completed on June 25, 1997.

AIRCRAFT INFORMATION

According to fueling records provided by the operator, the 1980 model airplane was topped off with 21.3 gallons of 100LL aviation fuel prior to departing on the local flight. The airplane was equipped with two Lycoming O-360-A1G6D engines, rated at 180 horsepower. The left engine, serial number L-26465-36A, had accumulated a total of 339 hours since its last major overhaul. The right engine, serial number L-303-71A, had accumulated a total of 1,575 flight hours since its last major overhaul. The airplane featured counter rotating propellers. Both propellers were equipped with unfeathering accumulators.

The last annual inspection was completed 96 hours prior to the accident. The airplane was maintained by the operator at their maintenance facilities located at the Addison Airport. An estimate of the weight of the airplane at the time of the accident places the airplane within its weight and balance limits.

Another DPE, who flew the accident airplane on a previous flight on the afternoon of the accident, was asked to comment on the condition of the airplane. He stated that the airplane performed flawlessly and no maintenance discrepancies were found during the flight.

The airframe and engines were found to be in compliance with applicable airworthiness directives. A review of the airframe and engine maintenance records by the FAA inspector and the NTSB investigator-in-charge, did not reveal evidence of any anomalies or uncorrected maintenance defects.

METEOROLOGICAL INFORMATION

The nearest weather reporting station was located at the Addison Airport, located 10 miles to the south of the accident site. The recorded weather at 1530 reported clear skies, with a temperature of 90 degrees Fahrenheit and a dew point of 61 degrees. The winds were reported from 180 degrees at 15 knots, gusting to 20 knots. The altimeter setting was reported at 29.73 inches of Mercury. The IIC calculated the density altitude at 2,948 feet.

A carburetor icing probability chart was checked to determine if the conditions at the time of the accident were conducive to the formation of carburetor icing. According to the chart, the weather conditions at the time of the accident were conducive to carburetor icing in "the glide and cruise power configuration."

AERODROME INFORMATION

The Frisco Airport (DDJ), also known as the North Dallas Jetport, is located 2 miles west of the City of Frisco. The airport is unattended and no services are available. The 5,450 feet long by 100 feet wide concrete runway (17/35), and its low density of traffic make the airport a popular place for flight training.

WRECKAGE AND IMPACT INFORMATION

The airplane impacted a corn field approximately 975 feet west of runway 17 on a measured heading of 304 degrees magnetic. The wreckage came to rest at 33 degrees 08.655 minutes north, and 96 degrees 51.401 minutes west. Physical evidence and ground scars at the site indicated that the airplane impacted the ground left wing low in a slight nose low attitude, with the landing gear and flaps in the retracted position.

Fragments of red glass, later identified as portions of the left navigation light for the left wing, were found in a gouge mark at the initial point of impact. The fiberglass wing tip for the left wing was found approximately 12 feet from the initial impact point.

After impacting the ground, the airplane slid for 140 feet, and came to rest on a measured heading of 215 degrees. All aircraft components and debris associated with the impact were found within a 150 foot radius from the initial point of impact.

Both engines separated from the airframe during the impact sequence. The right engine came to rest in the vertical position on the left side of the fuselage, near the root of the left wing. The propeller assembly for the right engine was found separated from the engine at the propeller flange. The engine sustained minor fire damage. The dual magneto remained attached to the engine. The starter flywheel was also found separated from the engine. The shaft of the magneto was rotated by hand and the impulse coupling operated but no spark was produced at any of the posts. The ignition harness was destroyed by fire. The propeller governor, carburetor, starter, alternator, and vacuum pump remained attached to the engine. The spark plugs, rocker box covers, and the vacuum pump were removed. The engine crankshaft was rotated by inserting a special tool into the vacuum pump drive. Thumb compression was established, valve train continuity was determined and continuity was established to the accessory gears.

The left engine came to rest on the right side of the fuselage. The propeller assembly remained attached to the engine crankshaft. The left engine sustained severe fire damage. The dual magneto, engine driven fuel pump and ignition harness were destroyed by fire. The muffler was crushed. The carburetor and propeller governor were fire damaged. The started, alternator, and vacuum pump remained attached to the engine. The bottom spark plugs were removed and found unremarkable. The rocker box covers were removed to examine the valves and springs. The crankshaft was rotated and there was valve action, thumb compression was present, and continuity was established to the accessory gears. The propeller governor for the left engine was fire damaged but still attached to the engine, with the control attached. The governor's speed lever was found at the 9 o'clock (feather) position. Neither propeller governor could be tested due to the thermal damaged sustained.

The propeller blades for the left engine sustained only minimal leading edge damage. One propeller blade was bent aft approximately 45 degrees and was fire damaged, while the opposite blade was bent forward about 30 degrees. Neither propeller blade exhibited any significant leading edge damage. No rotational damage was noted on the propeller spinner or propeller bulkhead.

The propeller blades for the right engine did not exhibited any appreciable twisting or bending; however, the tips of the blades exhibited leading edge gouges and chordwise scratches. The blades appeared to be at a high blade angle at the accident site. Two large imprints identified as propeller slash marks from the right propeller were found separated by 2.5 feet, at approximately 8 feet from the initial point of impact. The propeller assembly for the right engine (counter-rotating engine) was found beyond the propeller slash marks.

Flight control continuity was established from the cockpit to all the flight control surfaces. Engine control continuity could not be established due to both engines becoming detached from the airframe; however, the proper hardware and portions of the cables were found attached to the throttle and mixture linkages for both engines.

The landing gear (hydraulic) and flaps (electric) were found in the retracted (up) position. The elevator trim was found in the 14 degree down tab (nose up) position. The rudder trim tab actuator was found extended one inch, which according to the representative from the aircraft manufacturer, was consistent with five degrees of right trim tab deflection (nose left trim).

The fuel selectors were destroyed by fire; however, the fuel valves for both engines were found aligned to their respective main fuel cell. Fuel was found in the fuel lines for the left engine. Both integral fuel cells were compromised by impact and fire damaged.

The engine and flight instruments, all switches, controls and levers, the circuit breaker panels, and all of the avionics equipment were destroyed by a post impact-fire.

Examination of the wreckage at the accident site did not reveal any evidence of pre-impact mechanical failure or malfunction.

See enclosed wreckage diagram for details of the wreckage distribution pattern.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was not performed due to the condition of the remains. Toxicological tests were negative.

FIRE

A post-impact fire destroyed the cabin area and right wing of the airplane. No evidence of pre-impact fire was found by the investigators during the field portion of the investigation. No soot or evidence of smoke was found on the inside surfaces of any portions of windshield and window plexiglass recovered at the site.

SURVIVAL ASPECTS

One of the eye witnesses made a 911 call from a cellular phone at 1508. The call was received by the Denton County Sheriff Department and forwarded to the Frisco Police and Fire Department. The fire department was located less than 2 miles east of the airport and units of the fire department arrived within 3 minutes to extinguish the fire and rescue the injured pilot.

The airplane was equipped with an ELT. The ELT was not activated by the impact.

The airplane was equipped with doors at both of the pilot and copilot stations. Both pilot stations were equipped with shoulder harnesses.

TEST AND RESEARCH

The Hartzell propellers were examined on June 9, 1998, under the supervision of the NTSB IIC. The tear down /examination of the propellers was inconclusive in determining the amount of power being developed at the time of the impact. The hubs and pitch change mechanism for both propellers did not show any remarkable markings that would indicate propeller blade angles at the point of impact. The examination determined that neither propeller had indications of high power output at the time of the impact. Likewise, neither propeller appeared to be in the feather position at the point of impact. See enclosed report for details of the examinations.

ADDITIONAL DATA

The wreckage was released to the owner's representative upon completion of the investigation.

NTSB Probable Cause

The pilot's failure to maintain control resulting in an inadvertent stall while performing simulated single engine maneuvers during a practical test for a multiengine rating.