FTW98FA165

The experimental homebuilt airplane was destroyed when it impacted trees following a loss of engine power during the takeoff/initial climb. Several witnesses reported that the engine sputtered then it lost power. Post-accident metallurgical examination revealed radial and circumferential cracks on the valve seat head of the #3 exhaust valve. The combustion chamber face of the valve contained sites of surface tearing where there was a lack of fusion of the coating to the base metal. Voids at the interface between the coating and the base material contained aluminum oxide, a material used during surface preparation operation.

History of flight:

On March 26, 1998, at 1610 central standard time, a Velocity 173 RG Elite homebuilt experimental airplane, N173VE, was destroyed when it impacted trees and terrain following a loss of engine power during the takeoff/initial climb from the North Little Rock Municipal Airport, North Little Rock, Arkansas. The airplane was owned and operated by private individuals under Title 14 CFR Part 91. The private pilot and the passenger received fatal injuries. Visual meteorological conditions prevailed for the local personal flight and a flight plan was not filed. The flight was originating at the time of the accident.

Witnesses were interviewed by the NTSB investigator-in-charge (IIC). A pilot, located at the police base of operation building parallel to runway 17, observed the airplane during the takeoff and stated "I could hear a vibration like a prop[eller]. As the aircraft lifted off, there was certainly a problem with control, it would porpoise, yaw, and roll approximately 20 degrees on each axis. The engine was increasing and decreasing RPM rapidly. All these difficulties could be seen [and] heard during the flight until just before impact then the engine stopped."

A witness, standing on the ramp area parallel to the runway, observed the airplane proceeding down runway 17 "abort the takeoff and taxi back to the end of the runway." The aircraft then successfully took off and when it was about 500 feet [agl] the right wing dipped and the plane dipped a little to the right, turned right on course, and headed over Camp Robinson [National Guard Facility adjacent to the North Little Rock Municipal Airport]. I then heard the engine "sputter and attempt to restart." Subsequently, this witness observed the airplane maneuvering "very low, just above the trees" as if it was returning to the airport.

A mechanic at the airport observed the airplane abort a takeoff and taxi back to runway 17. During the taxi, he noted that the engine was not running smoothly and another witness reported the sounds of the engine as "ragged [and] sputttering."

Another witness/pilot reported that the pilot obtained a weather briefing prior to the flight. Several days prior to the accident, this witness recalled that the "pilot and the fixed base operator had a conversation concerning the failure of the fuel pump. According to the witness, the pilot stated the engine ran at 1,400 RPM with the fuel boost pump. The pilot was discussing the possibility of switching from an in line fuel pump installation to a parallel installation."

A pilot at the airport observed the aircraft's departure and after a few seconds heard the motor "start to surge high to low RPM (maybe 5 times)" and then stop.

A witness at Camp Robinson stated that the engine "died and restart[ed] 3 times before I saw it come up below the tree line. It arced high over the street and nose dive[d] into [the] trees." Another witness at Camp Robinson heard the engine of the airplane "sputter and quit, start back up, stop and start back up again, then quit." This witness said he heard the airplane crash and explode.

Another witness reported that 3 days (March 23, 1998) prior to the accident, the airplane departed runway 05 and when the airplane was 100 feet to 200 feet AGL, the engine sputtered and lost power. The airplane entered a glide and landed on runway 05 without further incident.

Numerous witnesses reported that the winds were from the south at 15 to 20 knots. They, observing the post crash fire and smoke, called 911. Local and Camp Robinson authorities responded to the scene. The Magellan GPS location of the accident site was 1 nautical mile 235 degrees from the airport at 34 degrees 49.42 minutes North, 92 degrees 16.39 minutes West.

Personnel information:

A review of the FAA records revealed that the pilot obtained his private pilot certificate on January 8, 1990. On his third class medical certificate application form, signed on February 11, 1997, the pilot reported 1,200 hours of accumulated flight time. The medical certificate limitation required the pilot to wear lenses for distant vision and possess glasses for near vision. Medical records indicted that the pilot was diagnosed with diabetes that was controlled by diet.

The pilot received a factory checkout (1.3 hours) in the Velocity aircraft. The pilot logbook was destroyed in the post impact fire.

Aircraft information:

According to information obtained from the builder, FAA, the manufacturer, and the Velocity Owner's Flight Manual, the Velocity 173RG (s/n 301) N173VE, was registered to the current owner on February 28, 1996. The 4 place experimental homebuilt composite airplane was issued the FAA airworthiness certificate on May 6, 1997. The aircraft design incorporated tricycle landing gear and swept wing with NASA-developed winglet system. The winglet consists of an upper and lower cambered surface at each wing tip. Maximum gross weight is 2,250 pounds. The engine was a pusher configuration.

The fuel system consisted of two 30 gallon wing tanks with a mechanical engine driven fuel pump that transfers fuel to the carburetor. An auxiliary electric fuel pump provides backup for the engine-driven pump and fuel pressure redundancy during low altitude operation.

According to the manufacturer, Franklin engine s/n 2611100047 was delivered to the United States from "PZL-RZESZOW"-Spolka Akcyjna (SA), who holds the Polish GICA Type Certificate No. CB-129 and the FAA Type Certificate No. E9EA, in July 1995. There with no accessories installed at the time of delivery.

During telephone interviews, conducted by the IIC, with the builder, and internet correspondence from the pilot and/or the builder with other Velocity builders, the following information was reported for N173VE. The Franklin (6A-350-C1R, S/N 2611100047 CB-129, 205 horsepower, 2,800 rpm, 10.5:1 compression ratio) engine with 10 hours of running time was purchased from Aero Center, in the State of Oregon. Subsequently, the Franklin engine was derated (190 horsepower, 8.5:1 compression ratio) to operate on 93 octane automotive fuel. Derating was done by the builder and involved replacing the 10.5 pistons with new 8.5 pistons (pistons manufactured for engine 4A-235-B31,-B4) from "PZL-RZESZOW"-Spolka Akcyjna (SA). The camshaft was re-profiled in the U.S. to the 8.5 Franklin engine camshaft specifications. Ten hours of ground test running was accomplished prior to the first flight. The propeller was changed in January 1998 to an increased pitch propeller designed for the Franklin engine by IVO Propellers. The airplane was reported to cruise at 190 mph in the derated configuration.

According to the builder, at 107 hours of total time, while on cross country flight at 8,500 feet msl and an rpm of 2,550, the engine driven fuel pump failed. The disabled mechanical pump restricted the flow provided by the electric boost pump limited the engine operation to 1,400 to 1,500 rpm's. The airplane was landed without further incident. The builder examined the engine driven pump (AC4886) and found that the flapper valve housing had disintegrated and partially blocked the fuel passageway. Following this loss of engine power, the builder modified the fuel system by installing a second boost pump (NAPA 7-9psi) parallel to the existing serial fuel system. One-way flow valves were installed in each parallel outlet line. One fuel line had a mechanical pump to pump the fuel to the carburetor and an electrical boost pump. The parallel line had a second electrical boost pump. During taxiing in 98 degree temperature conditions, the pilot had experienced a loss of engine power due to vapor lock. Subsequently, the builder installed a return line with an electrically operated solenoid valve whereby the fuel in the line could be returned to the left fuel and the lines filled with cooler fuel from the l