Jabiru J450, Руководство конструктора, Страница: 307 / 343

Jabiru J450 Constructors Manual
Testing>Calibrate fuel gauges
Tuesday, April 6, 2010 307 of 343
Calibrate the fuel gauges
Fit the fuel gauge calibration decal around each wing tank gauge opening in the wing root
with the Zero indication on the decal placed against the fuel gauge needle – at this point there
is no usable fuel in either wing tank.
The process now is to add 10 litres of fuel at a time to each tank in turn and mark carefully
what each gauge needle indicates on each decal (use a pencil initially), and at the same time
dip your fuel dipstick into each tank and mark carefully where the fuel level is on the dipstick.
If you have installed an engine management EFIS please refer to the documentation supplied
with the unit for details of how to calibrate the equipment during this task.
If any fuel runs out of the temporary line from the firewall it indicates that there is not enough
clamping pressure on a fuel line, so check carefully for any dribbling when the first fuel is
added to each wing tank and make sure that it is corrected before proceeding.
Continue adding fuel in 10 litre increments until each tank is full, noting at each stage the
gauge needle position for each tank each and marking the appropriate end and side of the fuel
dipstick. Each wing tank will hold approximately 60 litres of fuel.
Once both tanks are full and each decal and each end of the dipstick have all been marked,
remove the clamps from the fuel lines and check
very carefully for any sign of weeping or
leaking from the part of the fuel lines where the clamps were applied.
Any sign of a leak will require that the fuel be drained from both tanks (otherwise it will cross
feed from the full tank to the empty tank) and complete replacement of the leaking fuel line.
Note that fracturing of the fuel lines after clamping is a rare occurrence that is only likely to
happen if the fuel lines are very old, for example in a long-delayed build that has sat for many
years. If this is the case we strongly recommend that
all fuel lines be replaced before flight –
if one fuel line is weak then the others are very probably in a similar state.
Even if your fuel lines are new you must check each line carefully for leaks after clamping.
Once all of the fuel lines have been checked and there are no leaks the protective sheathing
can be refitted and lock wired back into place.
Flush all of the quick drains thoroughly – drain at least 500ml of fuel out of each one, more if
there is any sign of dirt or debris: flush until the fuel runs clean from each drain.
Now you must drain all but 20 litres from each wing tank in preparation for test flying: use
the temporary line from the firewall fitting and let both tank drain down to the 20 litre mark –
you can use your new calibrated fuel dipstick to check the fuel level.
If you are using ramp space at the refuellers you may wish to push the aircraft back out of the
way for the draining process, which can take some time. You may use the electric fuel pump
to speed the draining process up. Record the time taken to fill a 1-litre container both with and
without the use of the electric fuel pump and save the result for the
Final inspection checklist .
Once the draining process is complete, reattach the fuel line from the carburettor to the
firewall fitting and tighten the hose clamp and then refit and lock wire the fireproof sheath.
Mark the fuel gauge decals in a permanent manner. Keep your calibrated fuel dipstick in a
handy location such as a door pocket and consider making a spare copy, just in case.
This completes the Testing>Calibrate fuel gauges task.