Plane & Pilot
Tuesday, October 2, 2012

Amateur-Built Safety

The NTSB wants more done to improve amateur-built aircraft safety

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.

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