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Magneto Checks

What you’re checking, and why, and doing them while airborne and when running lean of peak EGT.  

Gemini Sparkle

Key Takeaways:

  • Aircraft spark-ignition engines utilize dual magnetos for ignition redundancy and enhanced power, generating electricity from engine operation without external power.
  • Pilots conduct routine magneto checks during engine run-ups, monitoring RPM drops on the tachometer to verify ignition system health against specified parameters.
  • Anomalies during mag checks, such as engine quitting or a lack of RPM drop, indicate significant issues like P-lead failures or fouled spark plugs, requiring specific pilot actions or mechanic intervention.
  • Magneto checks can also be performed airborne, and multi-probe engine monitors (EGT/CHT) offer advanced diagnostic capabilities to pinpoint specific cylinder or spark plug problems.
See a mistake? Contact us.

A typical aircraft spark-ignition engine isn’t at all like the one powering the vehicle your drove to the airport. Unless, maybe, you drove a vintage tractor or motorcycle. There are so many differences, listing them here would take up lots of space, and we really only want to focus on what pilots can do and learn about their magnetos from the cockpit.

As we should know from ground school, the magnetos use energy from the operating engine to create electricity. By rotating an armature near a magnet and then sending the resulting energy into a secondary coil, high-voltage electricity is created. The mags, in turn, are connected by a wiring harness to the spark plugs, usually two of which are in each cylinder.

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