With inhibiting fluid fed to the fuel inlet, the fuel system of an installed engine is inhibited
- by running it at idle.
- by dry motoring the engine.
- by pumping it in statically.
Explanation from PART66Online
An installed engine has its aircraft services, so the starter turns it with the ignition off and inhibited while the fluid is fed in, and the engine's own fuel pump carries it through the filter, control unit, flow divider and manifold. The run is dry: nothing reaches the burners to ignite, and the fluid is drained or collected at the burner feed. The engine is not run on it, and no stationary process reaches those passages.
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alectaylorob asked · 28 Sep 2026
not sure this question makes sense are you trying to prime it or discard fuel after a wet start or what?
Community Comments (3)
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svenj88
28 Sep 2026
Actually, it is neither priming nor clearing a wet start, it is storage preservation: inhibiting oil is connected to the fuel inlet and the engine is dry motored on the starter with ignition off, so the engine-driven pump circulates the oil through the fuel control unit, lines and nozzles. Pumping oil in with the engine stationary is incorrect, because the engine-driven pump must turn to carry the oil through the whole system. The question stem is worth rewording slightly, to state that the inhibiting oil is supplied during motoring.
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alectaylorob
28 Sep 2026
Ahhh of course legend thanks for clearing that up! yeah definitely could be reworded slightly. Appreciate you getting back to me mate!
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PART66Online
28 Sep 2026
Thanks for raising this, you were right that the wording was unclear. The question has now been reworded to:
To inhibit the fuel system of an installed engine for storage, with inhibiting oil supplied to the fuel inlet, you should...
The correct answer is unchanged (dry motor the engine), but the stem now makes it clear that this is about preserving the fuel system for storage, not priming it or clearing a wet start. Thanks again for reporting it.
To inhibit the fuel system of an installed engine for storage, with inhibiting oil supplied to the fuel inlet, you should...
The correct answer is unchanged (dry motor the engine), but the stem now makes it clear that this is about preserving the fuel system for storage, not priming it or clearing a wet start. Thanks again for reporting it.
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