A precaution for the operation of an engine equipped with a constant-speed propeller is to

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If a pilot suspects that the engine (with a fixed-pitch propeller) is detonating during climb-out after takeoff, the initial corrective action to take would be to

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What type fuel can be substituted for an aircraft if the recommended octane is not available?

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During the run-up at a high-elevation airport, a pilot notes a slight engine roughness that is not affected by the magneto check but grows worse during the carburetor heat check. Under these circumstances, what would be the most logical initial action?

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