According to the NTSB, although the approximately 33,000 experimental amateur-built (E-AB) aircraft make up about 10% of the U.S. general-aviation fleet, they were involved in about 15% of all accidents, and about 21% of the fatal general-aviation accidents in 2011. The 2011 statistics were in line with what the Safety Board found in its recently completed study covering the 10-year period from 2001 to 2010 titled "The Safety of Experimental Amateur-Built Aircraft." Data on 2,134 accident aircraft was reviewed. Included with the powered fixed-wing aircraft were 97 helicopters, 75 gyroplanes, 16 gliders and four balloons.
The Safety Board says E-AB safety could be improved if the FAA had tougher documentation requirements for airworthiness certification when an aircraft is first built, more stringent flight-testing requirements, improved access to transition training for pilots and greater FAA support of efforts to facilitate training. The Safety Board also is encouraging the use of recorded data during flight testing, ensuring that buyers of used E-AB aircraft receive necessary performance documentation, and improving identification of aircraft as experimental and amateur-built in FAA aircraft registry records so it will be easier to track safety trends.
The NTSB's study revealed that the E-AB accident rate per 100,000 flight hours in 2010 was 21.17 compared with 9.49 for non-E-AB aircraft. The fatal accident rate in 2010 was 5.27 per 100,000 hours for E-AB aircraft, compared with 1.56 per 100,000 hours for non-E-AB aircraft.
Over the 10-year period from 2001 to 2010, about 23.2% of E-AB accidents had something to do with engine systems or components, 23.1% involved loss of control in flight, 9.8% were fuel related, and only 1.6% were weather related. That compares with 4.9% weather related, 10.9% fuel related, 13.7% loss-of-control related, and 14% powerplant related for non-E-AB aircraft.
The experimental amateur-built category was first adopted by the Civil Aeronautics Administration in 1952. At first, E-AB aircraft were primarily designed by the builder, or were built from plans shared among builders. Kits were introduced in the 1970s and now constitute the largest portion of experimental amateur-built aircraft. The FAA requires that the amateur builder be responsible for at least 50% of the construction. Some suppliers offer kits with sub-assemblies prepared at the factory, thus reducing complexity and required time for the amateur builder.
The Safety Board points out that someone who buys an E-AB aircraft on the used market must learn a lot about the aircraft, yet may have very little reference material and none of the firsthand knowledge that the builder may have acquired during the construction period. Systems, structure and handling characteristics may be unique to a particular aircraft. Obtaining transition training from a qualified instructor in an appropriate aircraft may be difficult.
While the NTSB's study highlighted differences between safety concerns for E-AB aircraft and the rest of the GA fleet, individual accidents demonstrate great commonality.
The Velocity RG is a four-seat, composite, single-engine aircraft in a canard configuration. On September 25, 2011, one of them was substantially damaged when it crashed after taking off from Sanford-Lee County Airport (TTA), Sanford, N.C. The private pilot was killed. Visual meteorological conditions existed.
At the time of the accident, a flight instructor and student pilot were doing touch-and-goes at TTA. While on downwind, the instructor heard the accident pilot announce he was taxiing to the runway, and soon after, heard the accident pilot announce the takeoff roll. The student reported that the accident airplane did not rotate for takeoff until it reached the 2,000-foot marker on the runway. He thought this was unusual, as his single-engine Cessna was normally off the ground in half that distance.
While on base, the student noticed the accident airplane at a very low altitude, in a continuous descending left turn. He said the airplane then disappeared from view, and a fireball appeared from the woods. The instructor contacted air traffic control on an emergency frequency and advised them of the accident and its location.
FAA records showed that the airplane's airworthiness certificate was issued in 1996. According to airplane and maintenance records, the airplane had accrued 143.8 total aircraft hours as of May 2011. The most recent annual inspection was completed March 1, 2008, at 131.8 total aircraft hours.
Over the approximate 15-year maintenance history of the airplane, the engine was disassembled three times, but none of the work qualified as an overhaul. The manufacturer recommended that engines that haven't reached the recommended limit for operational hours be overhauled in the 12th year.
According to fueling records at TTA, the airplane was last fueled on March 21, 2010, with 43 gallons of 100LL aviation gasoline. The airport manager stated that he was "reasonably certain" that the airplane had not flown since that date. In an interview, the airport manager said that the pilot/owner would come out to the airport, tinker with the airplane, start the engine, and taxi the airplane, but that the airplane had not flown "for years." According to the airport manager, the pilot/owner had mentioned on more than one occasion that he was trying to "get his medical back." However, the review of his records revealed that the pilot's medical certificate was still valid at the time of the accident.
In May 2011, the pilot/owner asked the aircraft maintenance facility at TTA to draft a list of discrepancies on the airplane that required correction in order to return the airplane to an airworthy condition for possible sale. Among the discrepancies was a frozen turbocharger waste gate. Investigators determined that the waste gate was stuck at approximately two-thirds of its travel. They could not determine how much of a loss of horsepower would be produced at the position in which it was found.
The NTSB determined that the probable cause of this accident was the pilot's intentional flight with known mechanical deficiencies, which resulted in a partial loss of engine power and subsequent collision with trees and terrain shortly after takeoff. Contributing to the accident was the pilot's lack of recent experience.
On April 3, 2011, an experimental amateur-built Lancair 360 crashed shortly after taking off from Chesapeake Regional Airport (CPK), Chesapeake, Va. The commercial pilot and the passenger were fatally injured. The pilot was taking his sister on a local sightseeing flight in visual meteorological conditions.
The pilot had flown in from his home base in Williamsburg, Va., with his son on board. They met family members for lunch. The pilot then offered to take his sister for a ride.
A witness saw the airplane take off from runway 23. The airplane was about a quarter of a mile beyond the departure end of the runway with its gear retracted when the engine began "hissing and sputtering." The witness saw the airplane then turn sharply to the right while losing altitude. After 90 to 110 degrees of turn, the nose dropped sharply, the turn stopped, and the nose began to recover from vertical before impacting the ground.
Another witness reported that when the airplane was about 150 to 200 feet above the ground, there was a loud backfire, followed by several smaller backfires. The airplane started turning back toward the airport and stalled. Additional witness statements were consistent, except that one thought that the airplane reached an altitude between 300 and 400 feet, and another stated that the airplane rolled 90 degrees, then headed "straight down," but continued rolling until it was upright again, and the pilot "tried pulling up but didn't have sufficient altitude." Another witness said "the airplane appeared to enter a classic 'stall/spin' and rolled inverted." The wreckage was located at the edge of a grassy field, on airport property, next to an undamaged perimeter fence. It was about 1,200 feet from the departure end of runway 23.
The pilot held a commercial pilot certificate, was a flight instructor, and had a current second-class medical. He was an active-duty U.S. Army pilot, Army instructor, instrument flight examiner and a graduate of the U.S. Navy Test Pilot School. A document indicated the pilot had 4,533 flight hours. Investigators requested flight data from the Army, but it wasn't provided.
The pilot's personal logbook indicated he had more than 50 hours in the accident airplane. Logbook remarks for a 2.7-hour flight on May 20, 2010, read: "left tank run dry landed w/3 gallons in right."
Both fuel tanks were found empty at the accident scene, but they had been compromised. Areas of vegetation at the crash site had turned brown from exposure to gasoline. Based on the amount of discoloration, investigators determined that there was very little fuel in the left tank and more fuel in the right tank.
The NTSB noted that the airplane was built from a Lancair II factory "fast-build" kit with some modifications. The Safety Board said a likely scenario is that the pilot took off with the fuel selected to the left tank, and once the loss of engine power occurred, he selected the right tank, which resupplied fuel to the engine before impact.
The NTSB determined that the probable cause of this accident was that the pilot didn't maintain airspeed following a loss of engine power, which resulted in a stall and spin. Contributing to the accident was the pilot's selection of the wrong fuel tank at takeoff, which resulted in fuel starvation and the total loss of engine power.