Power Plant Reciprocating Engines Exam
UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
Some cylinder barrels are hardened by - CORRECT ANSWER nitriding
Which of the following engine servicing operations generally requires engine pre-oiling prior
to starting the engine? - CORRECT ANSWER Engine installation.
One cause of afterfiring in an aircraft engine is - CORRECT ANSWER an excessively
rich mixture.
What does valve overlap promote? - CORRECT ANSWER Better scavenging and
cooling characteristics.
Which statement pertaining to fuel/air ratios is true? - CORRECT ANSWER The
mixture ratio which gives the best power is richer than the mixture ratio which gives
maximum economy.
Engine operating flexibility is the ability of the engine to - CORRECT ANSWER run
smoothly and give the desired performance at all speeds.
What is the best indication of worn valve guides? - CORRECT ANSWER High oil
consumption.
Direct mechanical push-pull carburetor heat control linkages should normally be adjusted so
that the stop located on the diverter valve will be contacted - CORRECT
ANSWER before the stop at the control lever is reached in both HOT and COLD
positions.
, Compression ratio is the ratio between the - CORRECT ANSWER cylinder volume
with piston at bottom dead center and at top dead center.
Which statement is correct regarding a four-stroke cycle aircraft engine? - CORRECT
ANSWER The intake valve closes on the compression stroke.
To reduce the power output of an engine equipped with a constant-speed propeller and
operating near maximum BMEP, the - CORRECT ANSWER manifold pressure is
reduced with the throttle control before the RPM is reduced with the propeller control.
What will be the likely result if the piston ring gaps happen to be aligned when performing a
differential-pressure compression check on a cylinder? - CORRECT ANSWER A worn
or defective ring(s) indication.
What is the principal advantage of using propeller reduction gears? - CORRECT
ANSWER To enable the engine RPM to be increased with an accompanying increase
in power and allow the propeller to remain at a lower, more efficient RPM.
The primary concern in establishing the firing order for an opposed engine is to - CORRECT
ANSWER provide for balance and eliminate vibration to the greatest extent possible.
Which of the following is most likely to occur if an overhead valve engine is operated with
inadequate valve clearances? - CORRECT ANSWER The valves will not seat
positively during start and engine warmup.
Which fuel/air mixture will result in the highest engine temperature (all other factors
remaining constant)? - CORRECT ANSWER A mixture leaner than a manual lean
mixture of .060.
Which of the following conditions would most likely lead to detonation? - CORRECT
ANSWER Use of fuel with too low an octane rating.
UPDATED ACTUAL QUESTIONS AND
CORRECT ANSWERS
Some cylinder barrels are hardened by - CORRECT ANSWER nitriding
Which of the following engine servicing operations generally requires engine pre-oiling prior
to starting the engine? - CORRECT ANSWER Engine installation.
One cause of afterfiring in an aircraft engine is - CORRECT ANSWER an excessively
rich mixture.
What does valve overlap promote? - CORRECT ANSWER Better scavenging and
cooling characteristics.
Which statement pertaining to fuel/air ratios is true? - CORRECT ANSWER The
mixture ratio which gives the best power is richer than the mixture ratio which gives
maximum economy.
Engine operating flexibility is the ability of the engine to - CORRECT ANSWER run
smoothly and give the desired performance at all speeds.
What is the best indication of worn valve guides? - CORRECT ANSWER High oil
consumption.
Direct mechanical push-pull carburetor heat control linkages should normally be adjusted so
that the stop located on the diverter valve will be contacted - CORRECT
ANSWER before the stop at the control lever is reached in both HOT and COLD
positions.
, Compression ratio is the ratio between the - CORRECT ANSWER cylinder volume
with piston at bottom dead center and at top dead center.
Which statement is correct regarding a four-stroke cycle aircraft engine? - CORRECT
ANSWER The intake valve closes on the compression stroke.
To reduce the power output of an engine equipped with a constant-speed propeller and
operating near maximum BMEP, the - CORRECT ANSWER manifold pressure is
reduced with the throttle control before the RPM is reduced with the propeller control.
What will be the likely result if the piston ring gaps happen to be aligned when performing a
differential-pressure compression check on a cylinder? - CORRECT ANSWER A worn
or defective ring(s) indication.
What is the principal advantage of using propeller reduction gears? - CORRECT
ANSWER To enable the engine RPM to be increased with an accompanying increase
in power and allow the propeller to remain at a lower, more efficient RPM.
The primary concern in establishing the firing order for an opposed engine is to - CORRECT
ANSWER provide for balance and eliminate vibration to the greatest extent possible.
Which of the following is most likely to occur if an overhead valve engine is operated with
inadequate valve clearances? - CORRECT ANSWER The valves will not seat
positively during start and engine warmup.
Which fuel/air mixture will result in the highest engine temperature (all other factors
remaining constant)? - CORRECT ANSWER A mixture leaner than a manual lean
mixture of .060.
Which of the following conditions would most likely lead to detonation? - CORRECT
ANSWER Use of fuel with too low an octane rating.
