NTSB Determines Pilot Error, Engine Failure Both Factors

The NTSB has issued a probable cause report in an accident which fatally injured the pilot of a Vans RV-4 kit-built airplane and his passenger in Oklahoma in May of 2010. The aircraft's engine failed moments after takeoff, and the pilot was left with few options. The board determined that one critical decision he made was not the right choice. The NTSB determined that the probable cause(s) of this accident to be a loss of engine power shortly after takeoff for undetermined reasons. Contributing to the accident was the pilot's decision to make a 180-degree turn at low level.

Vans RV-4 File Photo

CEN10LA276

History Of Flight
On May 29, 2010, about 1000 CDT, a single-engine Covell RV-4 kit airplane, N74RV, received substantial damage when it collided with terrain following a loss of engine power shortly after takeoff from Airman Acres Airport (OK93), Collinsville, Oklahoma. The private rated pilot and passenger sustained fatal injuries. The airplane was registered to and operated by a private individual. Day visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91 personal flight.

A witness located on the airfield, first heard and observed the airplane start, and then taxi to the north end of the runway. He stated that the pilot did a run-up, taxied to the centerline of the runway, and then started the take-off run; everything appeared “normal.” The witness added that when the airplane got to an altitude of about 150 feet, “the engine quit, and it got quiet.” The airplane then made a “sharp” turn back to the airport, the left wing dropped with the nose of the airplane pointing towards the ground. The airplane disappeared from sight due to trees; however, the witness reported that he heard the crash, and then saw smoke rising from behind the trees.

Personnel Information
A review of FAA records revealed that the pilot held both a private pilot and a repairman-experimental aircraft builder certificate. His most recent FAA third-class medical certificate was issued on August 4, 2009. A review of the pilot's logbook failed to identify his total hours of flight experience; however, approximately 330 hours were in the accident airplane. The records also indicate that the airplane flew about 0.5 hours in 2009 and 2008, and 8.5 in 2007.

Aircraft Information
The airplane, which is known as a Vans RV-4 was built from a kit, and completed by the pilot on January 23, 1999. The airplane held an experimental airworthiness certificate in the amateur built category, and had accrued about 330 total aircraft hours. The most recent annual (Condition) inspection was completed July 17, 2009.

The airplane was equipped with a Lycoming O-320-D1A four-cylinder air-cooled engine.

Meteorological Information
At 0953 the automated weather reporting station located about 8 nautical miles south of OK93 at the Tulsa International Airport (TUL), Tulsa, Oklahoma, reported; a clear sky, winds from 150 degrees at 4 knots, 8 miles visibility, temperature 79 degrees Fahrenheit (F), a dew point of 69 degrees F, and altimeter setting of 29.89.

Wreckage And Impact Information
An examination of the aircraft wreckage was conducted by the NTSB Investigator-in-Charge (IIC), an FAA inspector, and a technical representative from the engine manufacturer on June 9, 2010. The wreckage consisted of the left-and-right wings, the empennage section, and the aircraft engine. Much of the cockpit/cabin area was consumed by a post-crash fire. The major components of the airplane were accounted for at the scene.

The airplane wreckage was located in a flat, grassy pasture just off airport property. The initial impact point was a small crater, about 50 feet from the airplane. The airplane wreckage was resting on the ground in the upright position, with the main landing gear collapsed. The engine compartment, inboard section of each wing, and cabin area all experienced heat/fire damage during the post crash fire. The rear section of the empennage, including the stabilizers appeared intact and moved freely on their hinges from stop-to-stop.

The forward, outboard section of the left wing was buckled back towards the wing spar; the rest of the leading edge of the wing was wrinkled, distorted, and contained rips in the aluminum skin. The right wing’s leading edge was wrinkled and distorted along the entire span. Flight control continuity for the ailerons and elevator were established from the respective control to the cabin area; continuity for the rudder was confirmed to the foot pedals.

One blade of the two-bladed, fixed-pitch wood propeller was fractured and separated near the hub; the remaining blade which remained attached, appeared unmarked.

The airplane’s engine experienced heat damage from the fire, with both, left and right magneto housings partly melted, additionally, the fuel pump was also partly consumed by the fire. During the examination of the engine, the crankshaft was rotated by hand; continuity was established through the power and valve trains to the accessory section. Compression and suction was confirmed using the "thumb" method. The spark plugs were removed and appeared “normal” when compared to the Champion Spark Plug Wear Guide (P/N AV-27). The carburetor was removed from the bottom of the engine and partly disassembled. A trace amount of fluid remained in the carburetor’s bowl and tested “positive” for water using the paste method. It was also noted that several rain showers had passed over the area and wreckage, between the time of the accident and the examination.

A reason for the loss of engine power could not be determined.

Medical And Pathological Information
The Office of the Chief Medical Examiner, Tulsa, Oklahoma, performed the autopsy on May 30, 2010. The autopsy concluded that the cause of death was "Internal injuries due to blunt force trauma".

The FAA, Toxicology Accident Research Laboratory, located in Oklahoma City, Oklahoma, conducted toxicological testing on the pilot. The results were negative for items tested.

FMI: www.ntsb.gov