Abnormal Engine Instrument Indication - Airplane Emergency Procedure

The AFM/POH for the specific airplane contains information that should be followed in the event of any abnormal engine instrument indications. The table shown in Figure 1 offers generic information on some of the more commonly experienced in-flight abnormal engine instrument indications, their possible causes, and corrective actions.

Malfunction
Probable Cause
Corrective Action
Loss of rpm during cruise flight (non-altitude engines)
Carburetor or induction icing or air filter clogging
Apply carburetor heat. If dirty filter is suspected and non-filtered air is available, switch selector to unfiltered position
Loss of manifold pressure during cruise flight
Same as above
Same as above
Turbocharger failure
Possible exhaust leak. Shut down engine or use lowest practicable power setting. Land as soon as possible
Gain of manifold pressure during cruise flight
Throttle has opened, propeller control has decreased rpm, or improper method of power reduction
Readjust throttle and tighten friction lock. Reduce manifold pressure prior to reducing rpm
High oil temperature
Oil congealed in cooler
Reduce power. Land. Preheat engine
Inadequate engine cooling
Reduce power. Increase airspeed
Detonation or preignition
Observe cylinder head temperatures for high reading. Reduce manifold pressure. Enrich mixture
Forthcoming internal engine failure
Land as soon as possible or feather propeller and stop engine
Defective thermostatic oil cooler control
Land as soon as possible. Consult maintenance personnel
Low oil temperature
Engine not warmed up to operating temperature
Warm engine in prescribed manner
High oil pressure
Cold oil
Same as above
Possible internal plugging
Reduce power. Land as soon as possible
Low oil pressure
Broken pressure relief valve
Land as soon as possible or feather propeller and stop engine
Insufficient oil
Same as above
Burned out bearings
Same as above
Fluctuating oil pressure
Low oil supply, loose oil lines, defective pressure relief valve
Same as above
High cylinder head temperature
Improper cowl flap adjustment
Adjust cowl flaps
Insufficient airspeed for cooling
Increase airspeed
Improper mixture adjustment
Adjust mixture
Detonation or preignition
Reduce power, enrich mixture, increase cooling airflow
Low cylinder head temperature
Excessive cowl flap opening
Adjust cowl flaps
Excessively rich mixture
Adjust mixture control
Extended glides without clearing engine
Clear engine long enough to keep temperatures at minimum range
Ammeter indicating discharge
Alternator or generator failure
Shed unnecessary electrical load. Land as soon as practicable
Load meter indicating zero
Same as above
Same as above
Surging rpm and overspeeding
Defective propeller
Adjust propeller rpm
Defective engine
Consult maintenance
Defective propeller governor
Adjust propeller control. Attempt to restore normal operation
Defective tachometer
Consult maintenance
Improper mixture setting
Readjust mixture for smooth operation
Loss of airspeed in cruise flight with manifold pressure and rpm constant
Possible loss of one or more cylinders
Land as soon as possible
Rough running engine
Improper mixture control setting
Adjust mixture for smooth operation
Defective ignition or valves
Consult maintenance personnel
Detonation or preignition
Reduce power, enrich mixture, open cowl flaps to reduce cylinder head temp. Land as soon as practicable
Induction air leak
Reduce power. Consult maintenance
Plugged fuel nozzle (fuel injection)
Same as above
Excessive fuel pressure or fuel flow
Lean mixture control
Loss of fuel pressure
Engine-driven pump failure
No fuel
Turn on boost pumps.
Switch tanks, turn on fuel
Figure 1. Commonly experienced in-flight abnormal engine instrument indications, their possible causes, and corrective actions

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