Instrumentation may indicate your power setting, but cross-reference the available information to ensure your instruments are accurate.

by Ken Ibold

Tucked into a pocket in nearly every airplane is a book claimed to hold the secrets of what that airplane can do – and what’s beyond its capabilities. From engine start to shutdown, the pilot’s operating handbook (or aircraft flight manual) promises to give true and accurate indications of the airplane’s speed, fuel burn, takeoff/landing performance, load-handling ability and operating procedures.

Most pilots, however, take the book numbers with a grain of salt. Cruise speeds, for example, are notorious for being optimistically presented in the book – if they’re even presented at all. Fuel burn figures may apply only to a well-instrumented engine being flown at mixture settings that…