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FAA Flight Engineer Reciprocating Engine (Basic) Knowledge Test Practice Test

The FEP practice material focuses on reciprocating-engine principles relevant to flight-engineer knowledge, including fuel-air mixture, ignition, lubrication, engine structure, and propeller control. Its sample questions examine how components function and how operating conditions such as high power affect engine behavior. The bank also includes concepts such as preignition, carburetor heat, and oil-pressure indications.

Exam overview

Exam providerFederal Aviation Administration
Exam codeFEP
CategoryAviation

About the FAA Flight Engineer Reciprocating Engine (Basic) Knowledge Test Exam

Useful preparation involves connecting engine-system components to their effects on operation. For fuel and ignition, distinguish mixture-related power or temperature effects from the magneto’s role in producing spark, and recognize how preignition differs from normal combustion. For lubrication, relate wet-sump oil storage to pressure circulation, pressure indication, and relief-valve function. Engine-structure questions call for understanding how the crankcase supports and encloses moving parts, while valve-lifter questions involve maintaining valve-train clearance. Propeller-governor items test the relationship between governor action and selected engine speed on a constant-speed propeller. These connections support practical interpretation of engine indications and control behavior rather than isolated memorization of component names.

Sample Practice Questions

Review a selection from this exam's published US Practice Tests practice bank.

Question 1

What is a likely effect of an excessively lean fuel-air mixture at high engine power?

  1. AReduced combustion temperature in every operating condition
  2. BIncreased risk of overheating or detonation
  3. CAutomatic increase in cylinder displacement
  4. DLower exhaust temperature under all conditions
Show answerCorrect answer: B

At high power, an excessively lean mixture can raise combustion temperatures and increase the risk of detonation or overheating, depending on engine design and conditions. Mixture operation should follow the applicable engine and aircraft instructions.

Question 2

In a magneto ignition system, what is the magneto's basic role?

  1. ATo generate electrical energy for the ignition spark independently of the aircraft battery
  2. BTo control the engine's oil temperature
  3. CTo regulate the fuel-air ratio in each cylinder
  4. DTo drive the propeller governor directly
Show answerCorrect answer: A

An engine-driven magneto generates the high-voltage electrical energy needed for ignition. This allows the ignition system to operate independently of the aircraft battery during normal engine operation.

Question 3

In a reciprocating engine, what is preignition?

  1. AThe fuel-air charge ignites before the scheduled spark because of a hot spot or other ignition source
  2. BThe mixture fails to ignite because the spark plug gap is too small
  3. CThe exhaust charge ignites after leaving the cylinder
  4. DThe mixture ignites only after the piston begins its power stroke
Show answerCorrect answer: A

Preignition is ignition of the charge before the normal timed spark, often caused by an overheated surface or deposit. It can create severe thermal and mechanical stress.

Question 4

In an engine with a wet-sump lubrication system, where is most of the engine oil stored during operation?

  1. AIn a sump or reservoir associated with the engine
  2. BIn the propeller hub only
  3. CIn the intake manifold
  4. DIn the exhaust collector
Show answerCorrect answer: A

A wet-sump system stores the bulk of its oil in a sump or reservoir that is part of or attached to the engine. The oil pump circulates oil from this supply through the lubrication system.

Question 5

What is the main purpose of an engine oil pressure indication?

  1. ATo show the amount of fuel delivered to the cylinders
  2. BTo indicate the pressure of oil circulating through the lubrication system
  3. CTo measure the temperature of the cylinder heads
  4. DTo show the crankshaft's rotational speed
Show answerCorrect answer: B

The oil pressure indication reports the pressure of oil in the engine lubrication system. It helps the operator assess whether oil is being circulated under suitable pressure.

Question 6

What is the purpose of an engine oil pressure-relief valve in a pressure-lubrication system?

  1. ATo limit excessive oil pressure by regulating or bypassing flow when pressure exceeds its intended range
  2. BTo remove combustion gases from the exhaust manifold
  3. CTo increase fuel pressure whenever the throttle is opened
  4. DTo keep the propeller from overspeeding
Show answerCorrect answer: A

A pressure-relief valve helps prevent excessive oil-system pressure by controlling oil flow once pressure reaches the valve's regulating range. It does not serve as an exhaust, fuel, or propeller control.

Question 7

What is the primary purpose of a propeller governor on an engine equipped with a constant-speed propeller?

  1. ATo vary blade angle to maintain the selected engine speed
  2. BTo control the engine's ignition timing
  3. CTo adjust the carburetor float level
  4. DTo open the engine's cowl flaps automatically in all conditions
Show answerCorrect answer: A

A constant-speed propeller governor changes blade angle in response to engine-speed changes, helping maintain the selected RPM as engine load or flight conditions vary.

How to use this practice test

The free practice bank contains 50 published questions. Each session presents up to 20 questions selected at random, allowing repeated practice across engine-system concepts. Results appear after the session; use any missed items to identify whether the gap concerns component purpose, system operation, or an engine condition such as an excessively lean mixture.

Preparation tips

  • Sketch the wet-sump lubrication path and label where oil is stored, how pressure is regulated, and what the pressure indication tells the operator.
  • Compare normal ignition, magneto function, preignition, and excessively lean mixture effects; focus on causes and operating consequences rather than similar-sounding terms.
  • Trace how a constant-speed propeller governor responds to the selected speed, and distinguish its control role from the engine’s internal valve-lifter function.
  • For each engine component in the question bank, state its primary function and one operational indication or condition related to it.
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