NTSB Factual Report

HISTORY OF FLIGHT

On April 12, 2005, at 1746 central daylight time, an experimental Spearman Raptor single turbo-prop powered airplane, N750TP, was destroyed following a loss of control while on final approach to the George R Carr Memorial Air Field (BXA), near Bogalusa, Louisiana. The private pilot and his passenger were fatally injured. The airplane was registered to a private individual and operated by the pilot. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 91 personal flight for which a flight plan was not filed. The cross-country flight originated from the Daytona Beach International Airport (DAB), near Daytona Beach, Florida, at 1440, and was en route to the Austin-Bergstrom International Airport (AUS), near Austin, Texas, with a planned fuel stop at BXA.

A Washington Parish Sheriff Deputy interviewed two witnesses, who had similar observations. Both witness were in the Walmart parking lot, located approximately one and a half miles south of BXA. They observed the airplane flying in a northerly direction while at an approximate altitude of 150-200 feet above the ground. It appeared the left main landing gear was down and the right main and nose gear were in a stowed position. Shortly thereafter the airplane "barrow-rolled" to the left and "took a nose dive" below the tree line. The witnesses later observed smoke coming from the trees.

PERSONNEL INFORMATION

The pilot held a private pilot certificate for airplane single-engine land, and instrument airplane. His last Federal Aviation Administration (FAA) third class medical was issued on October 19, 2004. At that time, the pilot reported a total of 2,000 flight hours. A logbook belonging to the pilot was found at the accident site. As of the last entry, dated November 16, 2003, the pilot had logged a total flight time of 1,738 hours. A review of the endorsements section of the logbook revealed that the pilot had completed a biennial flight review on September 4, 2004.

According to the airplane's owner, the pilot had accumulated a total of 3 to 5 hours in the accident airplane.

AIRCRAFT INFORMATION

Manufactured by an individual in 2002, the retractable tricycle geared pressurized low-wing prototype airplane was of composite construction. The airplane was powered by a Walter turbo-prop (750 shaft horsepower) which was coupled to a three bladed constant speed propeller. The cockpit contained two seats in a tandem arrangement and was equipped with a dual screen Electronic Flight Instrument System (EFIS).

The airplane's airframe and engine logbooks were not available for review during the course of the investigation.

According to the airplane's owner the airplane had accrued approximately 60 flight hours.

AIRPORT INFORMATION

Runway 36 at George R Carr Memorial Air Field was 5,000 feet long and 100 feet wide. Pilots were advised to make left traffic patterns when operating at the airport. The airport elevation was 119 feet above sea level.

METEOROLOGICAL INFORMATION

At 1755, the Automated Weather Observation System (AWOS) at George R Carr Memorial Air Field, reported wind from 290 degrees at 14 knots gusting to 19 knots, visibility 10 statute miles, clear of clouds, temperature 77 degrees Fahrenheit, dew point 44 degrees Fahrenheit, and barometric pressure setting of 29.77 inches of Mercury.

WRECKAGE AND IMPACT INFORMATION

The main wreckage came to rest in heavily wooded area approximately 2,068 feet south of the approach end of runway 36 and about 940 feet west of the extended centerline. The Global Positioning System (GPS) coordinates recorded at the accident site were 30 degrees 48 minutes North latitude and 089 degrees 52 minutes west longitude, at a field elevation of approximately 119 feet mean sea level (msl).

According to a Federal Aviation Administration (FAA) inspector, who responded to the accident site, the airplane came to rest in an inverted position and was destroyed by post-impact fire. All major components were accounted for at the scene, but due to fire damage a control continuity check could not be performed.

A review of photos taken at the accident sight revealed that the propeller was separated from the engine. All three propeller blades exhibited leading edge damage, bending, and the outer tips of two propeller blades were torn off.

MEDICAL AND PATHOLIGCAL INFORMATION

The Washington Parish Coroner in New Orleans, Louisiana, completed an autopsy on the pilot.

The FAA Toxicology and Accident Research Laboratory located in Oklahoma City, Oklahoma, performed toxicological testing of specimens of the pilot.

TESTS AND RESEARCH

A mechanic and FAA inspector performed a teardown examination of the Walter turbo-prop at Diemech Turbines Incorporated, near DeLand, Florida. The mechanic reported the first and second stage stator labyrinth seals, power turbine nozzle, and inner combustion chamber labyrinth seals showed signs of rotational damage. The main driveshaft planetary hub to propeller flange was twisted in a clockwise direction. He further reported, "no mechanical defects or failure could be found."

ADDITIONAL INFORMATION

Data recovered from the EFIS, which was recorded in five-second intervals, revealed the pilot approached the airport from the southeast on an approximate heading of 285 degrees. About 1.85 miles from the airport, while at an altitude of 852 (msl), the pilot began a descending right turn for a straight in approach to runway 36. The data further revealed that the pilot continued to descend on an average glide path of 3.6 degrees.

When the airplane was approximately 4,600 feet from the runway threshold, it was at an altitude of 492 feet msl, at an indicated airspeed of 129 knots, a left bank of 5.8 degrees, heading of 6 degrees, and a 3 degree nose down attitude. When the airplane was approximately 3,583 feet from the threshold it was at an altitude of 402 feet msl, at an indicated airspeed of 122 knots, a left bank of 9.9 degrees, heading of 2 degrees, and a level attitude. While approximately 2,534 feet from the threshold the airplane was at an altitude of 342 feet msl, at 127 knots, a left bank of 23.1 degrees, heading of 340 degrees, nose up attitude of 10.2 degrees, and additional engine power was applied. The last datum point was estimated as 1,984 feet from the threshold. At that point the airplane increased to an altitude of 472 feet msl, indicated an airspeed of 119 knots, exhibited a right bank of 105.8 degrees, heading of 291 degrees with a nose down attitude of 56.9 degrees, and revealed a further increase in engine power. The airplane contacted the ground shortly thereafter.

Fueling records at Lynch Corporate Services located at Daytona Beach International Airport established that the airplane was last fueled on the day of the accident with the addition of 194 gallons of Jet A aviation fuel. The total capacity of the fuel tanks was reported as 205 gallons.

A test pilot, who was, hired to conduct a flight test program on the accident airplane, provided a written statement to the Safety Board's Investigator In Charge (IIC). The statement pertained to the flight characteristics he experienced during the approximately 35-40 flights and approximately 38 hours he had flown the airplane in the year prior to the accident.

The test pilot reported that "Approach and landing operations were fairly conventional from a configuration and handling standpoint, with the notable exceptions of the aircraft's low degree of lateral static stability, less than desirable aileron effectiveness, and high roll control forces required."

The test pilot stated that, while conducting sideslip tests for the purpose of determining the airplane's lateral stability characteristics, it was observed that the airplane would become laterally divergent at sideslip angles as small as five degrees. This characteristic was revealed when test were conducted at normal approach and pattern operation speeds of about 120 knots indicated airspeed (KIAS) or less. The instability effects were more pronounced when the landing gear was extended because the nose landing gear door added considerable surface area in front of the center of gravity.

During a sideslip, rudder forces reduced rapidly to zero and rates of lateral divergence were approximately ten degrees per second or greater. Due to the lateral instability characteristics, all subsequent test flights were planned and adjusted to increase known safety margins. No further attempts where made to move the CG aft for the purpose of stability tests and at no time had he tested the airplane at a center of gravity approximating full fuel loads or with passenger and or baggage on board.

The test pilot further reported the airplane "Exhibited unexpected and at times severe stall characteristics with inconsistent sharp break and roll off encountered which resulted in at times large amounts of altitude loss...At times the aircraft rolled inverted during the stall and required as much as 4,000 feet for recovery to normal flight conditions. Straight ahead stall breaks at times resulted in nearly 1,000 feet of altitude loss...The only appreciable and consistent improvements in stall controllability and minimization of altitude loss occurred after conducting 100 plus stall maneuvers." Stall speeds, at the weights tested, were approximately 70 KIAS in the landing configuration and about 75 KIAS in the flaps and gear up configuration. The test pilot concluded his flight-testing of the airplane in July 2004.

The test pilot provided the IIC with an email message that he reportedly provided to the airplane's owner at the conclusion of his flight tests. The email dated July 25, 2004 stated the following: "Several main issues exist that I would consider hazardous and/or unsafe which need further development on the specific aircraft. These issues include the proper functioning/affectivity of the aileron system, the aircraft's extremely weak directional static stability, as well as an intermittent loss of indicated fuel pressure during the application of takeoff power…The issues described in the email make a sign off and release of the aircraft into Phase II inappropriate."

A passenger, who had flown in the airplane with the accident pilot the day before the accident, reported the pilot had aborted two takeoffs due to low fuel pressure readings.

Because the logbooks were not available for review, it could not be determined if any modifications were made to the airplane since the test flights were concluded in July 2004.

Federal Aviation Regulation Part 91.319(b)(1)(2) stated: No person may operate an aircraft that has an experimental certificate outside of an area assigned by the Administrator until it is shown that (1) The aircraft is controllable throughout its normal range of speeds and throughout all the maneuvers to be executed; and (2) The aircraft has no hazardous operating characteristics or design features.

NTSB Probable Cause

The pilot's failure to maintain control of the airplane. A contributing factor was the pilot's lack of experience in the make/model airplane.