AIRCRAFT POWERPLANT SYSTEMS TEST
BANK EXAM 2025/2026
Description:
This exam covers the systems that support and operate aircraft engines —
including fuel, ignition, lubrication, cooling, exhaust, propeller control, starting,
and fire protection systems. It tests your understanding of how each subsystem
contributes to safe and efficient powerplant operation.
QUESTIONS
If the intake valve is opened too early in the cycle of operation of a four-stroke
cycle engine, it may result in
A – improper scavenging of exhaust gases.
B - engine kickback.
C - backfiring into the induction system.
D - improper ignition after compression.
Full-floating piston pins are those which allow movement between the pin and
E - the piston.
F - both the piston and the large end of the connecting rod.
, AIRCRAFT POWERPLANT SYSTEMS TEST
BANK EXAM 2025/2026
G- both the piston and the small end of the connecting rod. D - the
connecting rod.
In engine identification GTSIR 450-L, what is the type of engine?
H - In-line engine
I - Opposed engine
J - Radial engine
K - V-type engine
Its primary purpose is to allow fuel/air charge to enter the cylinder as early as
possible to increase engine efficiency and aid in cylinder cooling.
A - Valve lead
B - Valve lag
C - Valve overlap
D - Valve seat
Given the following data on valve position:
100 BTDC – intake valve opens
500 BBDC – intake valve closes
250 BTDC – Ignition occurs
, AIRCRAFT POWERPLANT SYSTEMS TEST
BANK EXAM 2025/2026
550 BBDC – exhuast valve opens
150 ATDC – exhaust valve
closes How long is the valve
overlap?
A - 25 degrees
B - 20 degreesC - 30 degrees
D - 15 degress
Among the given data, which are not causing detonation?
a. Using a fuel grade lower than recommended and allowing the engine to
overheat.
b. Wrong ignition timing
c. Sharp bends on induction system
d. Heavy engine load at low rpm
e. Fuel air mixture to lean
f. Incomplete scavenging
g. Compression ratios of 12:1 or higher
C - B and D
, AIRCRAFT POWERPLANT SYSTEMS TEST
BANK EXAM 2025/2026
D - E and G
E - C and F
F - A and E
During overhaul, the disassembled parts of an engine are usually degreased with
some form of mineral spirits solvents rather than water-mixed degreasers
primarily because
G – solvent degreasers are much more effective.
H – water-mixed degreaser residues may cause engine oil contamination in the
engine.
I – water-mixed degreaser cause corrosion.D – solvent degreaser are expensive.
Which one among the following blade have the highest aspect ratio?
J - A long blade with a narrow chord
K - A short blade with a wide chord
L - A long blade with a long chord
M - A short blade with a short chord
A diffuser design in such a way that it slows down the compressor discharge while
at the same time increase the pressure to its maximum value inside the engine.
BANK EXAM 2025/2026
Description:
This exam covers the systems that support and operate aircraft engines —
including fuel, ignition, lubrication, cooling, exhaust, propeller control, starting,
and fire protection systems. It tests your understanding of how each subsystem
contributes to safe and efficient powerplant operation.
QUESTIONS
If the intake valve is opened too early in the cycle of operation of a four-stroke
cycle engine, it may result in
A – improper scavenging of exhaust gases.
B - engine kickback.
C - backfiring into the induction system.
D - improper ignition after compression.
Full-floating piston pins are those which allow movement between the pin and
E - the piston.
F - both the piston and the large end of the connecting rod.
, AIRCRAFT POWERPLANT SYSTEMS TEST
BANK EXAM 2025/2026
G- both the piston and the small end of the connecting rod. D - the
connecting rod.
In engine identification GTSIR 450-L, what is the type of engine?
H - In-line engine
I - Opposed engine
J - Radial engine
K - V-type engine
Its primary purpose is to allow fuel/air charge to enter the cylinder as early as
possible to increase engine efficiency and aid in cylinder cooling.
A - Valve lead
B - Valve lag
C - Valve overlap
D - Valve seat
Given the following data on valve position:
100 BTDC – intake valve opens
500 BBDC – intake valve closes
250 BTDC – Ignition occurs
, AIRCRAFT POWERPLANT SYSTEMS TEST
BANK EXAM 2025/2026
550 BBDC – exhuast valve opens
150 ATDC – exhaust valve
closes How long is the valve
overlap?
A - 25 degrees
B - 20 degreesC - 30 degrees
D - 15 degress
Among the given data, which are not causing detonation?
a. Using a fuel grade lower than recommended and allowing the engine to
overheat.
b. Wrong ignition timing
c. Sharp bends on induction system
d. Heavy engine load at low rpm
e. Fuel air mixture to lean
f. Incomplete scavenging
g. Compression ratios of 12:1 or higher
C - B and D
, AIRCRAFT POWERPLANT SYSTEMS TEST
BANK EXAM 2025/2026
D - E and G
E - C and F
F - A and E
During overhaul, the disassembled parts of an engine are usually degreased with
some form of mineral spirits solvents rather than water-mixed degreasers
primarily because
G – solvent degreasers are much more effective.
H – water-mixed degreaser residues may cause engine oil contamination in the
engine.
I – water-mixed degreaser cause corrosion.D – solvent degreaser are expensive.
Which one among the following blade have the highest aspect ratio?
J - A long blade with a narrow chord
K - A short blade with a wide chord
L - A long blade with a long chord
M - A short blade with a short chord
A diffuser design in such a way that it slows down the compressor discharge while
at the same time increase the pressure to its maximum value inside the engine.
