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

12.20.10. Describe the procedures and the precautions to be taken when hand-swinging apropeller to start an engine. 

Procedure
– Pilot at controls.
– Competent person to swing the propellor.
– Swing in a manner that allows the prop swinger to step back as they pull the prop through.

Precautions
– treat the ignition as live even if switched off.
– clear area of obsticles which could possibly trip the swinger.
– no loose clothing etc for swinger.

12.20.8. Explain the purpose and the typical procedure for conducting magneto checks.

Purpose
– to check that both magneto systems are operating correctly
Procedure (before flight)
– Dead cut check at low power. BOTH- L – R – BOTH
Checks that both systems are working before hi-power runup check.
– Magneto check at RPM given in Flight Manual. BOTH – L – Both – R – BOTH. Check RPM drop similar(within limits) for each system.
Procedure (after flight)
– (at idle RPM) BOTH – L – R – OFF – BOTH
to check the the system is dead when turned off.

– dead cut check at low power – 800 – 1000 rpm
– switxh briefly from BOTH – L – R – BOTH
– the engine should not cut as L or R is selected

12.20.6(including . the starter warning light). 

Starter Warning Light (if fitted)
– the starter warning light in the cockpit will glow while the starter is engaged
– should extinguish the moment the pilot releases the starter
– it will remain on if the starter relay “sticks”
– if this happens stop the engine (mixture to IDLE CUT-OFF)

12.20.6. Describe the operation and correct handling of typical ignition/starter switches

– There are two common types of starter switch:
– Rotary key operated in which the key when turned activates the magnetos and then when turned further activated the starter motor.
– Separate magneto switches with a push button starter engagement. This type is normally started with the left (impulse) mag on and the other mag switched on after start.
Starter motors should not be engaged continuously for long periods of time because of heat build up.

12.20.4. State the purpose and principle of an impulse coupling.

Impulse Coupling
– incorporated into one magneto usually the left mag.
– generates a high energy spark and delays or retards the spark timing during initial engine start
– makes it easier initially for the engine to fire and gain rpm

12.20.2. Describe the principal features of a typical magneto ignition system (dual,independent, engine-driven magneto systems with two spark plugs per cylinder). 

Magneto Ignition System
– Magneto is self contained electrical generator which provides high tension electrical current for the spark plugs
– sparks generated by the magnetos are distributed at the pre-determined time through high tension electrical leads to the appropriate spark plugs by the distributor which is built into each magneto
– high tension leads are often bound together to form an Ignition Harness