Yak 18T Flight Operations Manual
Page 60 of 82
Disclaimer: This manual is to be used as a reference only, it is based on translated Yak 18T Flight Operations
Manuals and has not been approved by the Yakovlev Design Bureau or any other authority.
•
If the fuel pressure is good, then it is a reasonable assumption that fuel is getting to
the carburettor, and if you are ruling out total mechanical failure or failure of both
magnetos, then the fault must be the carburettor
•
In this case if the throttle is
SET
about half open, and then the engine primed on
‘cylinder’, but using frequent but short strokes, the engine will run reasonably well.
Clearly long strokes will alternately drown and then starve the engine (I have not
done this myself, but according to those who have, it is not too difficult to establish a
position that keeps the engine running reasonably)
So remember what the primer does – on the ‘system’ side it is filling and pressuring the
carburettor, and it doesn’t matter how much is pumped in this way, since the excess will
always return to the main fuel tank, but on the ‘cylinder’ side it is priming into the super-
charger – i.e. effectively directly into the cylinders, and an excess on the ground will of
course wash oil off the cylinder bores, or indeed cause a fire as excess fuel comes down
through the carburettor or even out through the exhausts, while in the air the ‘cylinder’
primer can be a life saver with its ability to keep the engine going!
11.2.2. Pilot Actions in case of drop in Engine Oil Pressure
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If a drop in the oil pressure in the engine is detected, check the oil temperature. If the oil
temperature rises, then land immediately in the terminal area and shutdown the engine
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If flying beyond the terminal area, land at an alternate airfield or select an appropriate
landing field, and then after informing ATC, perform the landing
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In the case of a forced landing, adhere to the instructions given in the section on forced
landing in this operations manual and if possible, any assistance offered by ATC
11.3. Pilot Actions in case of drop in Fuel Pressure and Non-
Uniform Fuel Consumption
1.
Signs of fuel pressure drop can be -
•
irregularities in engine operations, followed by a drop in engine rpm, some boost
reduction and/or engine vibration or shaking
•
drop in fuel pressure as read on the fuel pressure gauge
2.
In case of a fuel pressure drop, the pilot is obliged to -
•
inform ATC
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turn the primer handle MOTOR PRIMING counter clockwise to the LINE position and
start pumping petrol into the fuel system, checking the fuel pressure with the help of
the pressure gauge
•
stop fulfilment of the mission and land the aircraft at the nearest alternate airfield or
landing field
•
if the fuel pressure on the instrument is not recovered and the engine continues to
run rough, move the primer to the CYLINDER position and start manual pumping, to
achieve the best possible engine conditions
•
If fuel readings are low and differ significantly, bank 5°-7° towards the tank
containing the least amount of fuel and continue flying until it is equal
11.4. Pilot Actions in case of Engine Vibration
If the pilot detects unusual aircraft vibration or shaking, proceed as follows –
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