[ Current AMA Safety Code
Application for your AMA license requires you to agree to comply to
[ Current TMC Field/Flying Guide ]
The following items will remind you of potential safety hazards/guidelines:
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the AMA Safety Code as a condition of your application
and it requires you to comply with your own club's rules.
T-H-I-N-K
#13 - 5/17/2005 - Flying Alone
Casa de Aero R/C Club of Arizona sports its own safety code in addition
to the mandatory AMA Safety Code. While the AMA strongly recommends
"flying with a buddy," One of the Casa de Aero rules, Rule 2.4 of the
Flying Field Regulations states:
"Solitary model aircraft flying is not permitted. At least two persons
must be at the flying field when model aircraft are flown. There must
be at least one responsible person, in addition to the model aircraft
pilot, to act as a spotter for manned aircraft flying in the vicinity
and to provide assistance in case of an accident or emergency."
The rationale for this rule is SAFETY. Picture a model aircraft with a
10" diameter bench saw blade on the front instead of a propeller. A
propeller running at 12,000 RPM can do just as much damage as a saw
blade to a finger, a hand, an arm or any other human appendage which
happens to get in its way! If you are the only one at the field and the
propellor tries to eat one of your appendages, just stop and consider
the difficulties you would encounter while you are getting yourself to
the emergency room.
First, you have to stem the gush of blood pulsating from the deep
laceration(s), probably with a handkerchief. Then you have to figure
out how to drive your car and hold the handkerchief in place at the
same time. Then you start to fret about having to leave your model,
support equipment and radio at the field with the gate unlocked. It
probably hasn't started hurting yet because you are still in shock,
but soon the throbbing will begin. You will start to become faint, either
from shock or from the loss of blood. Do you pull over or do you forge
ahead, hoping to get to the hospital before you pass out completely and
hit something or someone? Think how much easier things would have been
if you had a buddy with you to help out.
It is obvious from the above hypothetical situation that the second
person at the field should be a responsible adult, one who is capable
of driving who can assist you with first aid. Any person younger than
driving age would not be considered a "responsible person" even if he is
that grandson whom you think is the smartest person in the world.
from Flight Lines,
T-H-I-N-K
#12 - 5/14/2005 - High-G Maneuvers
Have you ever considered the stress placed on your airframe when you execute
high-g maneuvers, such as an abrupt 90 degree change in altitude when flying at
a high rate of speed?
First, let's consider the physics of it. We are taught that any mass in motion
will try to continue to move in the same direction even when forces are applied
to move it in another direction. The heavier and/or faster the object is moving,
the higher the stresses that will be induced. It has been estimated that the
airframe, or parts of it, can be subjected to forces far in excess of 50 Gs.
That means that a 6 pound airframe now weighs the equivalent of 300 pounds, or
more!
In your airframe, there are several things that must be considered.
Heavy items, like batteries or receivers or servos, will try to break loose
from their mounts. After all, a one-pound battery pack has an effective weight
of up to, or more than, 50 pounds. Those balsa mounts can split like toothpicks
under the stress; pushrods become loose or bent, and surfaces no longer act
normally. Wings can bend, hinges can break, clevises can open. In fact, high
speed photos show that wings bend and twist; even fuselages are deformed.
What was a controllable aircraft is suddenly an uncontrollable missile. Nobody
can predict if it will hold together or where it, or the pieces, will end up.
Such extreme maneuvers should never be attempted when the aircraft is moving
toward anyone or anything of value. Chances are pretty good someone will be
hurt, or worse, and something is going to be hit pretty darn hard!
Another consideration: repeated high-g maneuvers can result in micro-cracks in
the airframe. Failure may occur in a subsequent flight with normal-g loads, such
as loops or rolls.
By the way, how much do you know about the effects of stress-induced failure?
Is your aircraft an ARF, or did someone else build it? Is the design adequate
for the maneuvers you are attempting? Are the high-stress areas adequately
strengthened? Was it built for lightness or for strength? Etc, etc, etc.
LESSON: Plan any extreme maneuvers carefully and in a manner that leaves no
possibility of being harmful to man or property. It is a really good idea to
get permission before attempting them at the field so that everyone will be
attentive and taking any necessary safety precautions.
T-H-I-N-K
#11 - 5/14/2005 - Lithium Polymer Batteries
If you are using lithium polymer (lipo) batteries to power anything in your RC
systems, you need to be aware of some of the potential dangers associated with
the use of them.
Lipos are a tremendous advance in battery technology for applications in RC.
However, due to the chemistry of lipos, and the high potential energy they have,
there is always the possibility of fire. This can happen as a result of
over-charging, exceeding the current rating, mechanical abuse, etc. However,
they can be used safely be adhering to simple precautions:
NOTE: These recommendations made by FancyFoam Models on their website located
at:
T-H-I-N-K
#10 - 4/30/2004 - Check Your TX Antenna
Sometimes it is one small detail that causes potential safety problems!
With many flights and years of experience and a feeling of "I know what and how
to control model aircraft", I could have caused a serious problem.
Recently, while at my local flying field, with several other pilots and
spectators, I was test flying a new plane. The plane had never been flown
before, so I recruited another pilot to hand launch the aircraft for its maiden
flight. I asked that he stay with me as a safety observer until I completed my
flight. Sounds like I was following normal safety procedures!
I indicated that I would run the engine first and if it ran OK I might try a
flight. It ran fine, so we proceeded to the flight line. The other pilot
hand-launched the plane and it climbed out OK. It needed some trim, and as I was
trimming it, the place started doing maneuvers by itself! I managed to start a
turn to bring it back for a landing, and as it got close to me, it quit its
erratic flight, so I decided to do a fly by. As I started making a left turn, I
experienced control problems again. I quickly pulled off most of the power, and
on the down-wind leg of my landing pattern, just as I started a left turn at an
altitude of about a hundred feet, I lost all control of the aircraft, and it
went straight into the ground.
As this was not my first crash, I started to consider all the possible causes
for this type of erratic behavior - a list running through my head at supersonic
speed. Suddenly, the answer became as clear as day as I reached to turn off the
power to my radio. I found that my antenna was not extended!
I had missed one important step in my pre-flight! I had forgot to pull
out my antenna on my transmitter! Fortunately, nobody had been injured
and very little damage had been suffered by my crash landing, but the results
could have been injury to someone or damage to valuable property.
LESSON LEARNED: Make sure you complete your flight check BEFORE you start your
flight! Use a written check list until you remember it verbatim.
(submitted by Jack Hogan, member of Tyler Modelers Club)
T-H-I-N-K
# 9 - 4/23/2004 - Lithium Battery Safety
The following alert was issued by the AMA on April 23, 2004:
EMERGENCY SAFETY ALERT
Lithium Battery Fires
Lithium batteries are becoming very popular for powering the control and
power systems in our models. This is true because of their very high energy
density (amp-hrs/wt. ratio) compared to NiCads or other batteries. With high
energy comes increased risk in their use. The, principal, risk is FIRE which can
result from improper charging, crash damage, or shorting the batteries. All
vendors of these batteries warn their customers of these dangers and recommend
extreme caution in their use. In spite of this, many fires have occurred as a
result of the use of Lithium Polymer batteries, resulting in loss of models,
automobiles, and other property. Homes and garages and workshops have also
burned. A lithium battery fire is very hot (several thousand degrees) and is an
excellent initiator for ancillary (resulting) fires. Fire occurs due to contact
between lithium and oxygen in the air. It does not need any other source of
ignition, or fuel to start, and burns explosively.
These batteries must be used in a manner that precludes ancillary fire. The
following is recommended:
1. Store, and charge, in a fireproof container; never in your model.
These batteries CANNOT be handled and charged casually such as has been the
practice for years with other types of batteries. The consequence of this
practice can be very serious resulting in major property damage and/or personal
harm.
Safety Committee
T-H-I-N-K
# 8 - 4/09/2004 - Announce Your Intentions
My zagi was flying great! I had just made my turn to land on the runway
when I saw out of the corner of my eye that someone had stepped out onto the
runway, un-announced. I reacted by making a quick turn away from the pits, but
did not expect the sudden change in momentum to cause the large, one-pound,
battery pack to be catapulted from the plane! It did not escape, however, as the
one-foot-long power lead held fast and the battery pack became a pendulum
hanging below the zagi. Needless to say, all control was lost as I frantically
attempted to get the plane down. It circled over the pit and made a vertical
plunge to the ground between Mark Humphries and his plane which was sitting in
the pits.
Fourtunately no one was hit and no airplane was damaged, but only by luck.
LESSON LEARNED: Make sure you loudly announce your intention to step onto, or
cross, the runway. Failure to do so could cause injury to you or an innocent
bystander. Or it could cause loss of an expensive airplane.
(submitted by James Talley, member of Tyler Modelers Club)
T-H-I-N-K
# 7 - 4/06/2004 - Routing Wiring
When I was in serious training, the following incident happened that could have
resulted in injury or loss of property:
I was trained by my instructor to always do a quick check of the controls before
making the first flight at the field. Everything checked OK, so we proceeded to
attempt a takeoff.
Oddly, as soon as the LT-40 trainer rotated and lifted into the air, it
proceeded to do a very slow roll to the left which could not be corrected by
applying right aileron. The flight ended quickly as the trainer cart-wheeled
through the high grass to the left of the runway.
Fortunately, no damage was done to the trainer, but when we checked the aileron
servo, we found it was not plugged in! Strange, since we had just checked the
operation of the ailerons, and found them to work normally.
Upon closer scrutiny, we concluded that the lead to the aileron servo had
gotten looped around the horn of the elevator servo. When we applied 'up'
elevator to take off, the aileron servo lead was pulled loose by the elevator
servo!
LESSON LEARNED: Make sure to properly cable your servo leads so they are always
free from being entangled with other servos and linkages.
(submitted by James Talley, member of Tyler Modelers Club)
T-H-I-N-K
# 6 - 3/02/2004 - Using a Spotter
If more than one pilot is flying, we ask each pilot to be accompanied by a
'spotter'. A spotter has one job: he/she is there, not to watch his pilot's
plane, but to watch everyone else's planes. Each spotter should stand close to,
and slightly behind the pilot being helped.
A good pilot should be able to keep up with his/her own plane, but will not be
able to keep track of all the other planes in the air, at least not very
effectively. The spotter is there to help his/her pilot avoid being involved in
any kind of accident by telling him/her if another plane is landing, taking off,
veering off the runway, or approaching in a dangerous manner.
The spotter may have to take over the radio if the pilot is unable to continue.
This might be due to being unable to see, being attacked by insects, etc.
LESSON LEARNED:
Be a good member. If you see a second or third, or more pilot taking off without
a spotter, step in and help. It could save an accident from happening.
(submitted by James Talley, member of Tyler Modelers Club)
T-H-I-N-K
# 5 - 2/06/2004 - Restrain Your Model Safely
The following is from the "SAFETY COMES FIRST" column on page 54 of Model
Aviation, April 1998, by Gary A. Shaw:
"It Would Never Happen to Me: Throughout the years I've passed on stories sent
in by people who have been seriously chewed up by propellors. The intent is to
keep readers aware that propellors can be dangerous; provide information that
helps prevent an injury; and keep you aware that pain and suffering is just
around the corner if you get careless. Following is a story sent in by a modeler
whose unrestrained model got away from him as he started it at the field:"
"I was on the flightline adjusting the mixture on my unrestrained Sig LT-40 with
a pro .46. I was in front of the airplane holding it with one hand while making
carburetor adjustments with the other. After much tweaking, I hit the sweet spot
and got the Thunder Tiger so that it would idle smoothly and accelerate from
idle to full power in about two nanoseconds.
Being happy with the engine, I pulled it back to idle, let go of the now
completely unrestrained model, and bent over to pick up the transmitter with my
caster oil-soaked hand. You guessed it, my oily hand slipped and hit the
throttle lever full up. Having just received a thorough tuneup, the engine
instantly went to full power (remember the two nanoseconds) and lurched into my
leg.
The emergency room doctor said it looked like someone hit me with a hatchet. The
cut was so deep he had to use two layers of stiches. After God knows how many
stiches and $1,200 worth of medical bills, I now have three nice scars on my
left leg.
I still can't believe I did such an incredibly stupid thing. There are plenty of
simple and easy-to-make restraint devices available, but I thought it would
never happen to me. It did! All that damage from just a little ol' .46. I hate
to think what a big engine would have done."
T-H-I-N-K
# 4 - 1/24/2004 - Flying Toward Spectators
The following is from the SAFETY CORNER, page 6, of the Texarkana R/C Flyer,
September 2003, by Harold Poindexter:
"I had the opportunity one day to watch a program on TV about airshows. They
were talking about the safety factors and what can occur if these factors are
not taken into consideration. One of the topics that I found interesting is that
in the United States no aircraft involved in an airshow is allowed to fly
directly toward the spectators. The reason for this is because if anything
should happen to the aircraft it's momentum would carry it (or its pieces) into
the crowd. By flying either away [from] or parallel to the crowd, the plane, or
its wreckage, will be carried away from the spectators.
This safety factor should also carry into our flying. I have seen many pilots
make their turn directly toward the pits. This is a big NO NO! How many times
have you seen unexpected things happen to a plane that causes the pilot to lose
complete control? No matter what speed you are flying, chances are that when
something on your plane swarms it will continue to travel in the same directions
it was traveling when it broke. If it is traveling toward the pit area, then
guess where it is going! Even if it hits the ground before it reaches the pit,
some pieces could possibly leave the plane and enter the pit area. This could
cause serious damage to planes or pilots and would surely mess up your weekend!
When making your turn, be sure that you are past the pit area. Also keep into
consideration where the pit area is if it is extended such as it is when we have
our Big Bird or SMALL events. The people at the end of the pit area can be
injured just as well as someone in the center of the pits.
Just remember that big or small, fast or slow, an RC airplane can really injure
someone. Let's keep our hobby as safe as possible."
T-H-I-N-K
# 3 - 1/17/2004 - Transmitter Impound
The best way found yet to control transmitter (TX) usage at the field is to use
the TX impound. To the right of the Frequency Control Board (FCB) are mounted
modified drain tubes that are for impound of inactive TXs at the field.
Your TX should always be in the impound unless you are either (1) flying, (2)
starting your engine to fly, or (3) testing your radio system, such as range
testing.
When you arrive at the field, you should immediately place your TX in the
impound. When you get ready to use it, you should obtain the frequency tag from
the FCB. When you complete using your TX, you should place it in the impound and
put the frequency tag back in the proper slot in the FCB.
Not too complicated! But it will assure that you are the only one on your
frequency when you are ready to fly.
(submitted by James Talley, member of Tyler Modelers Club)
T-H-I-N-K
#2 - 1/14/2004 - Frequency Tag
A near-incident at the field last weekend should remind us that it is a club
rule, to always get the frequency tag for your channel before you turn on your
transmitter. A transmitter was accidentally turned on while a pilot using the
same channel was flying. A crash was narrowly averted. The pilot flying had the
frequency tag; the other pilot did not. A similar incident late last year
resulted in the loss of an airplane and severe damage to a vehicle in the
parking area.
(submitted by James Talley, member of Tyler Modelers Club)
T-H-I-N-K
#1 - 1/7/2004 - New AMA Safety Rule
Did you know it is against AMA rules for a pilot to allow any part of his
aircraft touch the ground intentionally except the landing gear?
Check the AMA Safety Code for 2004, above; RC Models, Rule 9.
This rule is intended to help prevent loss of control. It means that the AMA
does not approve of (1) touching the tail of your airplane while in a 3D hover,
and (2) touching the rudder of your airplane when making a low, inverted pass!
Don Tabor and Jerry Gill, co-editors
Prescott AZ
* Always keep a fire extinguisher or a large bucket of dry sand close by to use
if there is a fire.
* Use a charger made specifically for lipos. They require special charging
procedures. Do not charge using a charger designed for nicads or nickel metal
hydride batteries.
* Make absolutely sure the voltage and current settings you use to charge your
lipo pack is correct.
* Charge on a fireproof surface, such as brick or concrete.
* Do not charge near anything flammable.
* Do not ever charge in the house or automobile.
* Never leave your lipo batteries unattended while charging.
* Do not carry loose cells or packs in a pocket, bag or drawer where they can
short-circuit to any items. Transport packs and cells in a closed metal
container.
* Do not place cells or packs on any conductive circuit such as a metal table if
there is any chance of a short circuit.
* Always keep cells or packs out of reach of children and pets.
* Take special precautions to be sure that cells are not punctured, especially
by metal objects such as hobby knives.
* If a cell leaks electrolyte on your skin, immediately wash your skin
thoroughly with soap and water.
* Spill of electrolyte can be cleaned from models or work areas with methonal or
detertent-water solution.
* Lipos can be disposed of safely by fully discharging them before disposal. Use
a resistor or lamp of suitable size to accomplish the discharge.
* For long-term storage, charge packs or cells fully, then discharge to 50% or
60% of rated capacity.
http://www.fancyfoam.com/liposafe.asp
2. Charge in a protected area devoid of combustibles. Always stand watch over
the charging process. Never leave the charging process unattended.
3. In the event of damage from crashes, etc, carefully remove to a safe place
for at least a half hour to observe. Physically damaged cells could erupt into
flame, and, after sufficient time to ensure safety, should be discarded in
accordance with the instructions which came with the batteries. Never attempt
to charge a cell with physical damage, regardless of how slight.
4. Always use chargers designed for the specific purpose, preferably having a
fixed setting for your particular pack. Many fires occur in using
selectable/adjustable chargers improperly set. Never attempt to charge Lithium
cells with a charger which is not, specifically, designed for charging Lithium
cells. Never use chargers designed for Nickel Cadmium batteries.
5. Use charging systems that monitor and control the charge state of each cell
in the pack. Unbalanced cells can lead to disaster if it permits overcharge of
a single cell in the pack. If the batteries show any sign of swelling,
discontinue charging, and remove them to a safe place outside as they could
erupt into flames.
6. Most important: NEVER PLUG IN A BATTERY AND LEAVE IT TO CHARGE UNATTENDED
OVERNIGHT. Serious fires have resulted from this practice.
7. Do not attempt to make your own battery packs from individual cells.
Academy of Model Aeronautics
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Muncie, IN 47302
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