Amateur-built and experimental aircraft - Australian Transport Safety ...

ABAA Case study: Lancair 320
Probably one of the most significant, yet least acknowledged safety events in Australian ABE
aviation was the ABAA for the Lancair 320. This aircraft had been sold by the US
manufacturer in kit form since 1990 (Janes, 1993). At the time of evaluation by the Civil
Aviation Authority (CAA), 57 kits had been sold in Australia, and eight had been given
permits to fly (Carmen, 1992). The aircraft demonstrated poor longitudinal static stability and
this was considered unacceptable by the CAA. The CAA test pilots also found the aircraft
was prone to pilot induced oscillations, especially on takeoff. The following recommendations
were made by the regulator:
The aircraft requires an increase in tail volume and an increase in dihedral effect. If the
stall warning remains unchanged after modification to improve the longitudinal handling
characteristics, an artificial stall warning device should be installed. Further investigation
of the longitudinal dynamic stability, Dutch roll and longitudinal manoeuvre stability is
required.
Four test flights were conducted by test pilots who had graduated from the Empire Test
Pilots’ School, with the last flight being conducted by both builder and owner. The CAA said
that the 49 Lancair aircraft which had not yet flown would not be issued a permit to fly until a
retrofit fix was developed and fitted to the aircraft to improve the design’s stability
characteristics; the retrofit cost about $2,000. Lancair representatives were incredulous,
arguing that more than 300 Lancairs in 11 countries had accumulated 40,000 hours of flying,
and that the US Federal Aviation Administration (FAA) had not raised any concerns about the
safety of the Lancair 320 design. In the June 1992 edition of Aircraft Magazine, the Australian
Lancair representative Avtex said that the CAA was ‘mixing apples and oranges’ by using the
US Federal Aviation Regulation (FAR) 23 pitch stability standard for certified aircraft, which
they stated was never intended to apply to amateur-built aircraft (Carmen, 1992).
Figure 12: A Lancair 320 aircraft
In a July 1992 letter to the editor of Aircraft Magazine, the CAA Chief Test Pilot responded by
saying the ‘Lancair fail[ed] to comply with some very fundamental stability requirements,’
including positive stability. Further, he indicated the following:
In most countries amateur built aircraft attract no formal airworthiness requirements and
can be assembled and flown without any assess of the type of the national authority. This
is the case in the US. Despite this, both the FAA and the Experimental Aircraft
Association make the strongest possible recommendations regarding the importance of
adequate stability, but without any compulsion to comply.
Most importantly, the CAA Chief Test Pilot indicated that the poor longitudinal static stability
of the Lancair was easily amenable to rectification (Engelsman, 1992). Subsequently, two
design modifications were approved by the CAA (ABAA Number 88) and features of these
designs were subsequently incorporated into its certified aircraft. Part of the modification
increased the volume of the horizontal stabiliser.
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