FAA A&P Mechanic Powerplant Oral & Practical
Exam
Practice Questions & Verified Answers |
Comprehensive Aviation Maintenance Technician
Exam Review | 2026–2027
, w are conventional reciprocating engines classified? THey are classified according to cylinder arrangment with respect to the crankshaft
(in-line, V-type, radial and opposed), or according to method of cooling (liquid
cooled or air cooled)
What are the different types of piston rings? Compression rings, oil control rings, and scraper rings
What is the purpose of the oil control rings? They are used to control the thickness of the oil film on the cylinder walls
What may be the result of installing piston rings Excessive oil consumption
incorrectly?
What type of piston rods are commonly found in radial A master and articulating rod assembly
engines?
What type bearings are in general use in reciprocating Plain bearings, which are generally used for crankshaft, cam ring, camshaft,
engines? connecting rods, and accessory drive shaft bearings. Roller bearings, which are
used primarily as crankshaft main bearings, but have other applications as well. Ball
bearings, which are used for supercharger impeller shaft bearings, rocker arm
bearings in some engines, and as propeller thrust bearings
What is the indication of valve blowzy? Valve blowby is indicated by a hissing or whistle when pulling the propeller through
prior to starting the engine. A cylinder compression check should be made to
identify the faulty cylinder
What is the purpose of using more than one spring for If only one spring is used to close the valve, it will vibrate or surge at certain speeds.
valve closing? To eliminate this diffuctly, two or more springs, one inside the other are installed on
each valve. Each spring will vibrate at a different engine speed, and the spring
surge vibrations will be dampened. Two or more springs also reduce the danger of
weakness and possible failure by breakage due to heat and metal fatigue
What is the purpose of valve overlap? Valve overlap permits better volumetric efficiency and lowers the cylinder operating
temperatures
Describe the inspection you would give the valve springs They should be cleaned thoroughly, and then visually inspected for evidence of
during engine overhaul overheating, cracks, broken ends, and for compression strength
What is the purpose of using valves with sodium filled Some intake and exhaust valve stems are hollow and partially filled with metallic
stems? sodium. Sodium is used because it is an excellent heat conductor. The sodium
melts at about 208 degrees F, and the movement of the valves circulates the liquid
sodium which enables it to carry the heat from the valve head to the stem, where it
is dissipated through the valve guide to the cylinder head and cooling fins
What causes engine sudden stoppage? Striking an object or engine seizure due to internal damage
What type inspection must be made after sudden The propeller drive shaft must be checked for misalignment, and the propeller
stoppage of an engine due to striking an object? checked for track
What is the purpose of crankshaft dynamic dampers used Dampers are used to overcome forces which cause deflection of the crankshaft and
in aircraft engines? torsional vibration. These forces are generated by the power impulses of the
pistons. Crankshaft vibrations are reduced by placing floating dampers (weights) in
the counterweight assembly, particularly in a single throw type crankshaft
Exam
Practice Questions & Verified Answers |
Comprehensive Aviation Maintenance Technician
Exam Review | 2026–2027
, w are conventional reciprocating engines classified? THey are classified according to cylinder arrangment with respect to the crankshaft
(in-line, V-type, radial and opposed), or according to method of cooling (liquid
cooled or air cooled)
What are the different types of piston rings? Compression rings, oil control rings, and scraper rings
What is the purpose of the oil control rings? They are used to control the thickness of the oil film on the cylinder walls
What may be the result of installing piston rings Excessive oil consumption
incorrectly?
What type of piston rods are commonly found in radial A master and articulating rod assembly
engines?
What type bearings are in general use in reciprocating Plain bearings, which are generally used for crankshaft, cam ring, camshaft,
engines? connecting rods, and accessory drive shaft bearings. Roller bearings, which are
used primarily as crankshaft main bearings, but have other applications as well. Ball
bearings, which are used for supercharger impeller shaft bearings, rocker arm
bearings in some engines, and as propeller thrust bearings
What is the indication of valve blowzy? Valve blowby is indicated by a hissing or whistle when pulling the propeller through
prior to starting the engine. A cylinder compression check should be made to
identify the faulty cylinder
What is the purpose of using more than one spring for If only one spring is used to close the valve, it will vibrate or surge at certain speeds.
valve closing? To eliminate this diffuctly, two or more springs, one inside the other are installed on
each valve. Each spring will vibrate at a different engine speed, and the spring
surge vibrations will be dampened. Two or more springs also reduce the danger of
weakness and possible failure by breakage due to heat and metal fatigue
What is the purpose of valve overlap? Valve overlap permits better volumetric efficiency and lowers the cylinder operating
temperatures
Describe the inspection you would give the valve springs They should be cleaned thoroughly, and then visually inspected for evidence of
during engine overhaul overheating, cracks, broken ends, and for compression strength
What is the purpose of using valves with sodium filled Some intake and exhaust valve stems are hollow and partially filled with metallic
stems? sodium. Sodium is used because it is an excellent heat conductor. The sodium
melts at about 208 degrees F, and the movement of the valves circulates the liquid
sodium which enables it to carry the heat from the valve head to the stem, where it
is dissipated through the valve guide to the cylinder head and cooling fins
What causes engine sudden stoppage? Striking an object or engine seizure due to internal damage
What type inspection must be made after sudden The propeller drive shaft must be checked for misalignment, and the propeller
stoppage of an engine due to striking an object? checked for track
What is the purpose of crankshaft dynamic dampers used Dampers are used to overcome forces which cause deflection of the crankshaft and
in aircraft engines? torsional vibration. These forces are generated by the power impulses of the
pistons. Crankshaft vibrations are reduced by placing floating dampers (weights) in
the counterweight assembly, particularly in a single throw type crankshaft
