AME Reciprocating Engine Theory and Operation

Question 1

What is the correct firing order of the Lycoming O-320 four-cylinder horizontally-opposed aircraft engine?

Accepted Answer

1-3-2-4

Answer

The Lycoming O-320 uses a 1-3-2-4 firing order to evenly distribute power strokes across the crankshaft and minimize vibration.

Question 2

What does TDC stand for as used in reciprocating engine terminology?

Accepted Answer

Top Dead Center

Answer

TDC (Top Dead Center) is the piston position at its highest point in the cylinder bore, marking the boundary between the compression and power strokes.

Question 3

At what point in the 4-stroke operating cycle does ignition typically occur?

Accepted Answer

Near the end of the compression stroke slightly before TDC

Answer

Ignition is timed to occur slightly before TDC on the compression stroke so that maximum combustion pressure develops just after TDC for optimal power output.

Question 4

What is the primary safety advantage of a dual independent magneto ignition system in a reciprocating aircraft engine?

Accepted Answer

It provides redundancy so the engine continues running if one magneto fails

Answer

Dual magnetos are self-contained and independent of each other, so a failure of one magneto in flight does not stop the engine since the other continues to provide ignition.

Question 5

What type of lubrication system is standard on most horizontally-opposed aircraft reciprocating engines?

Accepted Answer

Wet sump with oil stored in the engine crankcase

Answer

Most horizontally-opposed aircraft engines use a wet sump system where oil is stored in the engine crankcase sump and circulated by an engine-driven gear pump.

AME - Aircraft Maintenance Engineer Practice Test

AME - Aircraft Maintenance Engineer Practice Test

AME Reciprocating Engine Theory and Operation