AME Reciprocating Engine Theory and Operation 3

Question 1

What is the purpose of dynamic counterweights installed on an aircraft reciprocating engine crankshaft?

Accepted Answer

To dampen torsional vibration at critical resonant RPM ranges

Answer

To add rotational inertia for smoother idling at low RPM

Answer

To balance oil distribution through the crankshaft passages

Answer

To compensate for minor propeller blade track differences

Question 2

What type of bearing is used for crankshaft main and connecting rod journals in most aircraft reciprocating engines?

Accepted Answer

Precision plain (sleeve) insert bearings

Answer

Tapered roller bearings

Answer

Deep-groove ball bearings

Answer

Needle roller cage bearings

Question 3

What is the primary objective of an engine break-in procedure after overhaul or cylinder replacement?

Accepted Answer

To seat new piston rings against the cylinder walls to establish proper compression and oil sealing

Answer

To verify that maximum power output meets the engine's type certificate specifications

Answer

To flush manufacturing residue and metal particles from the oil system

Answer

To calibrate the fuel injection system to the correct fuel flow schedule

Question 4

What is the function of the power enrichment (economizer) circuit in an aircraft float carburetor?

Accepted Answer

To enrich the mixture at high power settings to prevent detonation and provide cylinder cooling

Answer

To automatically lean the mixture during steady cruise for fuel economy

Answer

To provide additional fuel flow during cold-start primer operation

Answer

To prevent fuel starvation during sustained inverted flight maneuvers

Question 5

What does TBO (Time Between Overhaul) specify for a certificated reciprocating aircraft engine?

Accepted Answer

The manufacturer-recommended operating interval after which the engine should be completely overhauled

Answer

The mandatory interval between required 100-hour inspections

Answer

The maximum continuous run time before a mandatory oil change is required

Answer

The calendar-time limit before the aircraft must undergo a heavy maintenance check

Question 6

What does a differential compression test measure on a reciprocating engine cylinder?

Accepted Answer

The leakage of compressed air past piston rings and valves to assess internal cylinder condition

Answer

The engine's overall power output at a standardized RPM setting

Answer

The pressure differential between fuel injection and induction air at the injector nozzle

Answer

The ratio of intake-to-exhaust gas pressures during normal operation

Question 7

What does an excessive RPM drop on one magneto during the pre-takeoff magneto check most likely indicate?

Accepted Answer

A defect in that magneto's circuit such as a fouled spark plug, faulty ignition lead, or internal magneto fault

Answer

The engine has not yet reached proper operating temperature

Answer

The engine is operating normally and within limits on that magneto

Answer

Carburetor heat is inadvertently still applied during the run-up