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The switches operate in the "normally open" mode, so they have to close the circuit to kill
the engine. In the unlikely event of a switch failure, kill the engine using the choke. If this
fails, turn off the fuel. With the fuel turned off, the engine may take some minutes to stop, as
all the fuel in the carburetters must be used up.
Ensure the contact switches are off whenever you leave the aircraft. Failure to do so could
result in injury or death when the propellor is handled during the next pre-flight check
procedure.
Mixture control
The optional mixture control system works by applying
chambers, so reducing the fuel flow through the carburettor jets. The mixture leaning control is a valve on the
instrument panel which applies either ambient pressure (rich) or partial carburettor venturi pressure (lean) to
the float chambers. The pressure can be monitored by a gauge. Maximum leaning is limited by the size of
the air vent jet.
The mixture should be set fully rich at all times except when cruising at a steady altitude, speed and throttle
setting. The exhaust gas temperature (EGT) must be monitored when leaning the mixture, it must not
exceed 800C. Observe all other engine limitations before and after leaning.
Starter - Electric start
The starter is operated by start button on the instrument panel. The key switch must be in the ON position
for the starter button to function.
NOTE
The key switch only switches the power to the intruments, comms & starter. Remember to switch on the
•
ignition switches before start-up!
The hand throttle cutout switch option makes it necessary for the hand throttle to be CLOSED in order for
•
the starter circuit to operate.
4.8 SECONDARY STRUCTURES AND SYSTEMS - BRAKING SYSTEM
The compensated rear wheel brakes are operated by a foot pedal on the left side of the front fork steering
bar. Brakes may be cable operated drum or hydraulic disc type according to aircraft specification. A brake
locking device is provided for parking. To lock, press the brake pedal and, with the left hand, lift the adjacent
locking lever and engage one of its slots with the hoop on the side of the steering assembly. Release occurs
automatically when the brake pedal is pressed.
NOTE
Do not press on the end of the locking ratchet to engage parking brake. There is a risk it could bend.
•
The travel of the hydraulic brake pedal will be such that the locking lever will engage only in the first or
•
second notches. This is normal.
•
Use Dot 4 brake fluid e.g. Bendix Universal Dot 4 from a sealed container.
4.9 SECONDARY STRUCTURES AND SYSTEMS - FUEL SYSTEM
Fuel is pumped from the single tank below the seat by the engine pump via the fuel filter. The 912S
installation features a recirculation system which returns excess fuel to the tank. The tank is vented via a
pipe to discharge clear of the aircraft. A sump with water drain is provided. The tank may be 49L or 65L, the
65L tank has a third mounting point at the centre of the tank. Fuel is supplied to the carburettors via the main
shutoff cock.
Rotax 912/912S
T
he preferred fuel is 95 RON minimum octane rating unleaded petrol. 4 star leaded fuel (super) can also be
used. 100LL AVGAS can be used, but the high lead content causes more plug fouling, so use only when
necessary. Plugs should be checked at least every 25 hours if using AVGAS. If AVGAS is used more than
just occasionally, use only semi-synthetic motorcycle oil.
Whichever type of fuel is used, use a reputable source of supply and during your daily inspection, use the
water drain facility provided in the fuel tank.
Quik & Quik GT450 Maintenance Manual
th
29
March 2007
Issue 1
WARNING
!
reduced air pressure to the carburettor float
Push the drain mushroom upwards and sample the fuel in a
Page 30 of 54
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