A complete engine fire protection system on a turbine-powered aircraft consists of which two basic subsystems?
ACS code: AM.III.E
Correct answer: A fire detection system and a fire extinguishing system
Rationale: A fire protection system is divided into two functional parts: a detection system that warns the crew of a fire or overheat condition, and an extinguishing system that delivers an agent to put the fire out. The other choices name individual components but not the two-part division of the overall protection system.
Which type of fire detector senses fire by responding to the rate at which a monitored area's temperature increases?
ACS code: AM.III.E
Correct answer: Rate-of-rise (thermal switch) detector
Rationale: A rate-of-rise detector uses thermocouples or bimetallic elements arranged so that a rapid temperature increase, faster than normal engine warm-up, triggers the warning. Optical detectors sense radiant energy, and CO detectors sense a gas, not a rate of temperature change.
What is the principal advantage of a continuous-loop fire detection system over a series of individual spot detectors?
ACS code: AM.III.E
Correct answer: It provides more complete coverage of the fire hazard area
Rationale: A continuous loop runs as an unbroken sensing element around the entire hazard zone, so a fire anywhere along its length is detected, giving better area coverage than discrete spot units. Loop systems still require power and, like any system, can give false warnings, so those statements are incorrect.
A pneumatic (gas-filled tube) continuous-element detector triggers a fire warning when heating causes what to occur inside the sensing tube?
ACS code: AM.III.E
Correct answer: Gas pressure rises and closes the diaphragm switch
Rationale: In pneumatic detectors the sealed tube is charged with a gas; localized or average heating raises the internal pressure, which acts on a diaphragm that closes the alarm switch contacts. A drop in pressure instead indicates a leak (integrity fault), and the core-short mechanism describes a resistance-type loop, not a pneumatic one.
A fire detection system that gives a warning when actually heated but does not signal a fault when the loop is broken would most likely fail to indicate which condition?
ACS code: AM.III.E
Correct answer: An open (broken) sensing element
Rationale: Modern detection systems include integrity (fault) monitoring that flags an open in the loop so a broken element is not mistaken for a no-fire condition. A system lacking that feature would still alarm on real heat or certain shorts but would silently fail to reveal an open element, leaving the area unprotected.
What method is commonly used to determine whether an engine fire extinguisher container holds its required charge of agent?
ACS code: AM.III.E
Correct answer: Weigh the container and compare it to the specified charged weight
Rationale: The standard check of an installed extinguisher charge is to weigh the bottle and compare the result against the placarded full charge weight, since the agent quantity correlates directly to weight. Shaking is unreliable, and cartridge resistance verifies the firing circuit, not the agent quantity.
From where does an aircraft auxiliary power unit (APU) receive its fire-warning signal?
ACS code: AM.III.E
Correct answer: Its own dedicated fire-detection system.
Rationale: The APU is protected by its own dedicated fire-detection system because it must operate safely and unattended when the main engines are shut down. It does not rely on the engine fire-detection loops or share a common airframe system for its fire warning.