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A) Use positive frequency control.
Sections 5
and 6 of the AMA Radio Control Safety Code involve frequency control.
Section 5 reads "I will operate my model aircraft using only
radio-control frequencies currently allowed by the Federal
Communications Commission (FCC)." This reminds us that radio amateurs
are the only ones who can use the ham frequencies.
Section 6 discusses
the possible interference of radio transmitters operated within three
miles of each other and how to avoid such interference.
The FCC is that
federal government agency that controls the use of radio broadcast
frequencies in the United States. If this frequency control did not
exist, the use of the radio broadcast bands would be chaotic. There
would be constant interference between broadcast stations.
Radio
broadcast bands are dedicated to specific purposes. There are several
radio-frequency broadcast bands allocated for use in controlling flying
models: 27 MHz, 72 MHz, 50 and 53 MHz (only legal for licensed amateur
radio operators), and the recently authorized 2.4 GHz spread spectrum
band.
The majority of model-aircraft radios used in the US are in the 72
MHz band. Each broadcast frequency band has a set of discrete
frequencies within it that can be used. The 72 MHz band has 50
frequencies that are sometimes referred to as channels. Last month I
covered how, during your aircraft's preflight check, you would get the
frequency paddle for your channel.
In addition to the requirement that
our transmitters operate on allocated frequencies, we must prevent the
simultaneous use of two aircraft-control transmitters on the same
frequency from the same location (or sometimes within three miles of
each other). This will cause one or both aircraft to crash. Do not turn
on your transmitter within three miles of the flying field without
frequency authorization.
Frequency use at a flying field, that meets AMA
standards, will be positively and safely controlled by one of two
methods: a frequency control board or a transmitter impound. I have
already discussed the use of the frequency control board. Transmitter
impound is usually reserved for use during contests.
The transmitter
impound works like gun control in the Old West. "Want to come into town,
stranger? Check your gun right here and you can pick it up on your way
out of town."
With the transmitter impound, you turn in your transmitter
when you arrive at the field. You check it out when it is needed for a
flight. The person who issues it to you from the control station
verifies that no one else is using your frequency before he or she gives
you the transmitter.
If you are flying in a park or ball ground with one
of the lightweight park flyers, you can perform the following check on
frequency usage before turning on your transmitter. Hold onto your model
and turn on your receiver without turning on your transmitter.
If the
control surfaces move in a controlled manner, there is someone on your
frequency and you need to find the individual and coordinate use of the
frequency. If the control surfaces do nothing or deflect to full travel
and stay there, it shows that no one is controlling on this frequency.
It should be safe to turn on your transmitter.
Do not leave the receiver
on for an extended period without the transmitter's being turned on. To
do so could damage your servos by causing them to lock up at their
extreme travel. If you cause a loss of control by turning on an
unauthorized transmitter, you place others at serious risk of being hurt
by an out-of-control model.
Click on photo to view large image with caption
B) Use the pilots' stations. It is not
stipulated in the Safety Code, but the use and location of four pilots'
stations at a flying field are recommended in the AMA-member handbook.
At each flying site you will probably see four marked flying positions.
However, there is an exception to this rule. Air Combat matches permit
as many as eight fliers at one time with additional barriers, safety
gear, and greater separation distances between the flight operations and
spectators.
The pilot positions may be marked using circles on concrete,
using yellow concrete pads set in the grass, or using some other means.
Use them. The pilot-position markings are meant to provide physical
separation between pilots and radios. Their use also limits the number
of aircraft in flight at any time to four.
If there are already four
fliers on station, wait your turn. Limiting the number of models that
are airborne at one time minimizes the chance of a midair collision and
resulting crash. If you see that one of the pilots' stations is empty,
carry your airplane out to the runway. My club considers taxiing models
in the pit areas an unacceptable safety hazard. Taxiing is permitted on
the taxiways.
As you approach the runway edge, set the airplane on the
grass. Being considerate fliers, we do not carry the noisy aircraft
behind the fliers who are already on station. The noise would be a
distraction and would prevent them from noticing if their aircraft
suddenly had an engine out.
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