12.24.4(b) . starting an over-primed engine;
Over Primed engine
– turn the engine over through a few revolutions using the starter motor with the mixture control to IDLE CUT-OFF and throttle fully open.
– then select FULL RICH position close the throttle then “crack” it open to the normal starting position and try starting again but without priming
– if the engine fires during the clearing procedure immediately put mixture to FULL RICH and retard the throttle to normal starting position
12.24.4(a) . staring the engine in cold temperatures;
Cold engine / cold air
– requires maximum amount of priming
– in really cold conditions it can help to turn the primed engine over by hand (magnetos off) 2-3 revolutions to free it up and draw mixture into the cylinders. ( follow hand starting procedures)
12.24.4. In general terms, explain the procedures for:
12.24.2. State the safety precautions to be taken before starting the engine.
Area
– operational area of airfield with restricted access to public
– position aircraft facing into wind
– clear hardstanding area or firm grass area
– no loose objects or material which may cause damage if caught in slipstream
– areas to the front and rear should be cleared
Brakes
– park brake should be ON
– or chocks in place ahead of the main wheels
Fire Extinguisher
– awareness of the position of the nearest fire fighting equipment in case of fire at start up
Propellor Awareness
– make sure area is clear / warn bystanders re engine start up
– if someone in danger zone move mixture to idle cut-off
12.22. Ignition systems Solid State
12.22.8. Describe the operation and correct handling of ignition/starter switch systems.Sub Topic Syllabus Item
– Starter motor system draw large electrical currents and therefore create significant heat. For this reason there should be a rest between bursts of use and long duration engagement or continuous use of the starter is not recommended.
12.22.6. Explain the purpose and a typical procedure for conducting ignition integrity checks.
– Ignition integrety checks are conducted to ensure that the ignition systems are working correctly before a flight.
– typically each system is checked individually to ensure that it is performing within the parameters given in the aircraft flight manual.
12.22.4. Explain the advantages/disadvantages of solid state ignition systems.
Features
– advantage is the automatic adjustment of timing of the ignition spark during engine operation
– the microprocessor triggers the spark through a solid state switching device, the breaker points and the distributor of the magneto system are dispensed with
– disavantage is that the system requires a power supply to function. Back/redundant alternators provide power in the event of battery power loss during flight, but starting an engine with stand alone solid state system requires battery power.
– Improved ignition timing and longer stark duration results in cleaner fuel burn and improved economy over magneto ignition.
12.22.2. Describe the principal features and components of a typical solid state ignitionsystem.
Features
– advantage is the automatic adjustment of timing of the ignition spark during engine operation
-2 coils are used to generate the sparks – one to the cylinder nearing the end of the compression stroke and the other to its comnpanion cylinder on the exhausted stroke
– the microprocessor triggers the spark through a solid state switching device, the breaker points and the distributor of the magneto system are dispensed with.
12.20. Ignition Systems Magneto Ignition