We need to verify that our engine is functioning accordingly. This test is generally done at runway holding point.
Depending on the aircraft, RPM values may differ but the goal is always the same:
ﾠ1. Push the engine at high RPM
ﾠ2. Check magnetos at moderate RPM
ﾠ3. Set suddenly throttle to idle RPM
System check must include the assessment of oil pressure and temperature, exhaust gas temperature and engine manifold pressure.
Definition of Magneto:
An ignition magneto is a magneto that provides current for the ignition system of a spark-ignition engine, such as a petrol engine. It produces pulses of high voltage for the spark plugs.
The use of ignition magnetos is now confined mainly to engines where there is no other available electrical supply. It is also widely used in aviation piston engines even though an electrical supply is usually available.
As this is one of the most critical system, it must be then thoroughly checked.
Contrary to after-start check, at moderate or high RPM, magnetos should never be switched off. The risk is to damage the engine, and in particular, the exhaust line.
Before performing an engine run-up, make sure to apply brakes!
ﾠ1. To perform the engine run-up, proceed as follows:
ﾠ2. Increase throttle to match 2,000 RPM. Check oil temperature and pressure are in the green range.
ﾠ3. Slow down to 1,800 RPM. Perform magneto check on positions Left – Both -- Right - Both.
ﾠ4. Do not switch the ignition key to the "OFF" position!
ﾠ5. Suddenly close the throttle. Engine must not stall, nor drop below 500 RPM.
ﾠ6. Establish back 900 RPM.