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Could that have
happened
in
the United States?
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By
now, I am sure that most AMA members have heard about the
tragic accident that happened in Hungary that resulted in
the deaths of two spectators. A number of AMA members have
suggested that AMA conduct a full inquiry and report the
findings to the membership.
That concept is full of issues
that are difficult to resolve. In the first place, this
accident happened in Eastern Europe so our access to
information is limited, but the issue goes well beyond that.
The question becomes whether the sport is better served by
talking more about this tragic accident or discussing it
less; that isn't an easy question to answer. I decided that
some explanation of what happened would have more positive
elements than negative, so I will outline the situation as I
have been able to determine it.
I have had contact with aero
club officers in Germany and Hungary. The accident occurred
during an air show in Hungary. I believe the site was a
typical European aero club where full-scale aircraft—primarily
gliders—and model airplanes are part of the shared club.
The
person involved was an experienced German RC pilot, known by
many as a top-notch air-show flier. He had taken all of the
reasonable steps to ensure that there was no radio
interference, including flying a test aircraft at the site
for a few days before the event.
The accident occurred when
the model, a Giant Scale biplane weighing approximately 44
pounds, went out of control and crashed into the spectator
area. The airplane was flying from the right after
performing a turn-around maneuver when the pilot lost
control of it. The model rolled, veered to the left, and
crashed into the spectator area.
From when the pilot
apparently lost control until impact could be measured in
single-digit seconds. Unfortunately, the model hit and
killed a husband and wife who were taken to the air show by
their adult children.
After initial investigation of the
accident by the authorities, it was determined that a
broadcast station had transmitted signals on the frequency
on which the model was flying, effectively shooting the
aircraft down. The investigation is ongoing so this may not
be the final ruling.
Could that have happened in the United
States? The crash and the fatalities could certainly happen,
but the apparent cause is highly unlikely to occur here. We
are fortunate that we don't share our specific frequencies
with any other services, but the accident brings home the
need to be very careful with transmitter impound since
another RC transmitter could cause this type of control
loss.
This tragedy again brings up the subject of fail-safe.
I have not been able to determine with any authority whether
the model involved in this accident was equipped with
fail-safe or how it may have been set. I was able to find a
crude video of the accident, and after careful review I
think that the model probably did have some form of
fail-safe, which is common in PCM radios.
I couldn't
determine if it was set to low throttle from the video, but
it was apparent to me that the throttle position would have
had little effect on the speed of the aircraft at impact.
The model was in a shallow dive from when control was lost
until impact; it would not have slowed appreciably even with
the engine shut down.
This was a terrible accident and I'm
sure it will have a lasting effect on RC aeromodeling
throughout the world. We need to learn as much as we can
from this tragedy to avoid a similar occurrence in the
future.
While retarding the throttle with fail-safe would—or
perhaps did—have little effect on this accident, there is
little question that setting the fail-safe to retard the
throttle would be the prudent thing to do in most failure
situations.
In any situation, a fail-safe system cannot be
expected to work any better than the pilot's familiarity
with its operation and settings. If you are not completely
familiar with the fail-safe features of any of your radios,
it would be prudent to read the instruction manual and
become familiar with them. Till next month.
MA
Til next month ...
Dave Brown, AMA president
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