Service Instruction No. 1132 B

Magneto Drop-Off

  • Publications

Supersedes Service Instruction No. 1132A

June 18, 2010


All Lycoming Opposed Series Aircraft Engines with Magnetos.


During Pre-Flight Inspection

A basic magneto drop-off check based on engine speed is typically done during the pre-flight inspection to determine the loss of engine speed that occurs when magnetos are switched from BOTH magnetos to one (LEFT or RIGHT) magneto. The maximum drop-off limit is specified in most Lycoming publications as Revolutions Per Minute (RPM) from a stated engine speed.

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