Connect your adapter to the tank(s) to be filled, and
connect the filler hose to the adapter. Check for leaks
by opening a tank valve l/4-turn. Better to find the
leak when it is small than after the main supply valve
is open and/or the fuel pump is on.
If there are no leaks, open the tank valve full, then
back 1/4-turn. Open the liquid level indicator valve
(also called the 10 percent, 15 percent, 20 percent,
or spit valve) 1/4-turn. There is no need to open the
liquid level indicator valve any more than
1/4-turn if a pump is being used; it is only an indicator
and the less it is opened, the easier and faster it will
be to close. If fuel is going to be transferred by
pressure differential (often called decanting), you
should open the 10 percent valve to its full flow (about
one complete turn) because you are trying to lower
the pressure in the receiving tank so the propane will
flow from high pressure (the filling tank) to low
pressure (the receiving tank). Now the filler hose
valve may be opened and the fuel pump turned on.
There are only two ways to determine legally when a
propane tank is full, (1) from the liquid level indicator
valve spitting, or (2) from the weight of the fuel. Even
if the tank has a full-scale fuel gauge (0-100 percent),
it is not a legal measure.
As soon as the indicator valve spits, close the supply
valve and shut off the pump. Close the tank valve and
then close the indicator valve. There is a common
tendency to shut off the indicator valve first, but to
avoid overfilling the tank, the supply valve should be
Be careful draining the hoses, even if the system has
a bleed valve, as the propane drained from the filler
hose is cold and may burn bare skin.
Disconnect all filler hoses, reconnect the balloon fuel
lines, and check for leaks. Do not leave your hoses
open for nesting insects or dirt, and do not wait until
later to discover a leak. Put your system back together
and check it now.
Never overfill propane tanks. Propane expands with
heat and adequate head space must be allowed in the
tank. When the spit valve spits, shut off the fuel supply.
The hose coming off most propane suppliers' storage
tanks does not fit into most balloon tank's liquid valve;
therefore, an adapter is necessary. It is good practice
to carry and use your own adapter, as most propane
company adapters are worn and dirty and may damage
your fuel system.
Prolonging Hose Life
Some people fuel through the balloon's fuel lines
because it takes less time. This is not a good idea.
Fittings from fuel lines to the burners are not designed
to be used over and over. Fittings become rusted
because the cadmium plating is worn off by wrenches.
Fittings, possibly hoses, may then have to be replaced,
depending upon their serviceability. If you insist on
fueling through the lines, you should use two wrenches
so you do not disturb the burner fitting.
Another reason to have special fueling hose adapters,
and not to use the balloon fuel system, is that foreign
matter (dirt, rust, pieces of rubber, etc.) may become
lodged in your fuel hose. It is much better, and safer,
if such matter lodges in an adapter, or falls to the
bottom of the tank.
Hoses wear out by rubbing against things. When you
are fueling, make sure the fuel hoses are not abraded
in the process. During preventive maintenance, check
the position and security of hoses.
Propane is an appropriate and safe fuel for hot air
balloons, providing proper handling techniques and
safety precautions are followed.
Fuel systems are not standardized among
manufacturers. Certificated balloons vary from a
simple one-burner/one-tank system to complex
systems with three burners and eight tanks. Some tanks
are connected individually, some in series. Some systems have more tanks than hoses requiring the pilot
to disconnect and connect hoses in flight. It is very
easy to figure out a fuel management program for a
one-burner, one-tank balloon, but what is the best
fuel management system for a more complex system?
Most balloon fuel tank gauges are inaccurate. Vertical
tanks do not have room for the fuel gauge float arm to
read on a full-scale dial, and usually have dials that
read from 5 to 35 percent. Horizontal tanks allow
adequate room for the float arm and usually read from
0 to 100 percent. Tank gauge floats often stick and do
Through experience and good record keeping, a pilot
can develop the expertise to know approximately how
much fuel is required per hour. A wristwatch can be
a very dependable fuel gauge.
The best way to learn the fuel consumption of a
balloon is to check the time required to use the fuel
from one tank. To find out, you can make a flight,
running on one tank exclusively, timing how long it
takes to exhaust the fuel in that tank. (This should be
done only to establish your benchmark time. In
practice, a tank should never be emptied; 20 to 30
percent should be saved as a reserve.)
If you have two identical tanks, you will establish
how long it takes to use half your fuel. To establish
actual time you could fly on a tank, allowing the
amount of reserve you prefer, deduct 20 to 30 percent
from the time expended to exhaust the tank.
A simple time management plan follows. If you have
a two-tank system and like to land with 20 percent
reserve, you would inflate the balloon on one tank,
fly on that tank until the gauge reads 20 percent, note
the time it took to use the first tank, switch to the next
tank and be on the ground either when the second tank
gauge reads 20 percent or when the allotted time is
Once you have established your benchmark times,
you may wish to consider other fuel management plans.
Some pilots, with two-burner, two-tank systems, like
to switch back and forth between burners, making
constant affirmation that both systems are working.
You still land at either 20 percent or within your
An emergency plan for low fuel with a two-tank
system, if a landing site is not found before both tanks
are at 20 percent, would be to continue to fly on the
last 20 percent of one tank and save the second tank
for the actual landing. As the last quarts of propane in
a tank are used, the tank pressure decreases. Try to
save some normally pressurized fuel for the landing.
Which tank should be saved for the landing? This
decision should be made before the flight. Part of
your low-fuel plan should take into consideration any
differences between tanks. If only one of your tanks
supplies fuel to the pilot light and backup system, use
that tank last.
The important consideration for pilots to remember
is to pay attention, keep records, and always have a