AOPA Turbine Pilot Magazine - March 2025 - 93

my Cessna 310, some a whole lot faster. A
few are pressurized and/or turbine-powered.
These are serious aircraft. Is it any
wonder that E-ABs are nowadays the fastest
growing segment of the GA fleet?
So, am I jealous that the owners of
these gorgeous E-ABs are minimally regulated
by the FAA and can do pretty much
anything they want? You bet your life I am.
But are they safe?
Intuitively, you might think that these lessregulated
amateur-built airplanes are less
safe than certificated aircraft with their
FAA-blessed designs and burdensome regulatory
constraints. At first glance, you'd be
right about that.
The overall GA accident statistics are
a moving target. Fortunately, they've been
moving in the right direction: downward.
In the 1960s when I started flying, the accident
rate for GA was consistently more than
10 accidents per 100,000 hours. In 1970,
the rate peaked at 13.5 per 100,000 hours.
Since then, safety initiatives by the FAA and
industry plus improved technologies such
as GPS, ADS-B, iPads, electronic flight bags,
and satellite-downlinked real-time weather
in the cockpit have made GA much safer. In
2019, the NTSB reported 1,220 GA accidents
(233 of them fatal) for an accident rate of
4.87 per 100,000 hours (and a fatal accident
rate of 0.89 per 100,000 hours). This
is a huge improvement, and something we
can all be proud of.
E-ABs have fared less well. Historically,
the E-AB accident rate has been about three
times as high as the overall GA accident
rate-somewhere in the 20s per 100,000
hours. But this has also been improving
dramatically in recent years. In 2011, for
example, E-ABs constituted about 10 percent
of the GA fleet, but were responsible
for 15 percent of the total GA accidents and
21 percent of the fatal GA accidents. This
suggests that you are 1.5 times more likely to
have an accident flying an E-AB than flying
a certificated aircraft, and more than twice
as likely to have a fatal accident.
So, does this mean that the regulatory
burden of operating a certificated aircraft is
actually worth it in terms of greater safety?
The answer to that question gets a bit
complicated, mainly because some E-ABs
are a whole lot more experimental and
amateur-built than others. The E-AB fleet
comprises a wide range of designs, most
built from kits but some built from scratch,
most fairly conventional designs but some
very exotic and unusual, most fairly easy to
fly but some quite challenging. All of these
are combined into the overall E-AB accident
figures.
More than half of all E-AB accidents
involve engine failure, either as the proximate
cause or a contributing factor. While
many E-ABs are powered by certificated
engines (mostly Lycomings) or near-identical
clones thereof, others are powered by
a variety of noncertificated engines including
various automotive engine conversions
(like VW, Corvair, and Subaru). The data
shows that engine failure accidents are far
more likely with noncertificated engines
(particularly auto conversions) than with
certificated ones.
If you exclude the Phase
I flight test period,
Van's airplanes appear
to have an accident rate
that's comparable to
certificated aircraft.
By far the most popular and populous
E-AB aircraft is the Van's RV series.
Roughly 11,000 of them are now flying.
RVs come in a bunch of sizes and flavors.
Most are two-seat (some tandem, others
side-by-side), although the RV-10 is fourplace.
Many models can be configured
either as tricycle gear or taildraggers. Some
are designed for aerobatics, others optimized
for cross-country flying. Most are
Lycoming-powered although some have
Rotax 900-series engines.
The RV-series has a substantially lower
accident rate than the E-AB fleet as a whole.
But some RV models have better safety
records than others. An in-depth safety
study published in Kitplanes magazine
in January 2020 indicated that the RV-7,
RV-8 and RV-9 variants had less than half
the accident rate of the overall E-AB fleet
over the 20-year study period from 1998
through 2017. That would appear to place
these models at a comparable accident rate
with certificated aircraft. Interestingly, the
-7 is a side-by-side aerobatic, the -8 is a tandem
aerobatic, and the -9 is a side-by-side
cross-country machine; all three are available
in both trike and taildragger versions.
Another thing worth considering is
that a disproportionately large number of
E-AB accidents (particularly fatal ones)
occur during the initial Phase I flight test
period, which generally comprises the first
40 flight hours after build completion. No
big surprise there. This is a uniquely challenging
time when the aircraft's flight
characteristics and systems reliability are
unknown-they truly are " experimental "
at this point-and when the pilot is least
familiar with the aircraft. One study concluded
that 9 percent of E-AB accidents
occur in the first 10 hours of flight testing,
which if true would be a hideous hourly
accident rate if you do the math. When the
Phase I flight test period is excluded, E-AB
hourly accident rates drop considerably.
One way to avoid the Phase I Flight
Test risk is not to build an E-AB aircraft
but rather to buy one that has already
been built and taken through flight testing
by someone else, either an actual amateur
builder or a professional hired gun.
The percentage of E-AB owners who are
not the original builders has been rapidly
increasing. Fully half of today's owners of
Van's RVs bought rather than built them.
Best of both worlds?
Consider the following thought experiment:
Suppose the FAA created a
new aircraft classification that I'll call
" Experimental-Commercial Built "
(abbreviated " E-CB " ) consisting of commercially-built
type-certificated aircraft
whose owners elected to renounce the type
certificates and have them reclassified as
E-CBs instead. A previously certificated
aircraft that was transitioned to E-CB
could no longer be used for compensation
or hire and would be regulated by the FAA
just as if they were E-ABs.
Once transitioned from certificated to
E-CB, the aircraft could be modified without
the need for STCs or field approvals,
repaired using nonapproved parts, maintained
by the owner (or anyone else, for
AOPA PILOT / March 2025
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AOPA Turbine Pilot Magazine - March 2025

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