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Extinguisher container pressure outside graph limits

Aviation Mechanic Powerplant (AMP) practice question 7 of 7 on Engine Fire Protection Systems. ACS element AM.III.E.K5 · difficulty: standard. Want to answer it in a timed quiz? Use the Aviation Mechanic Powerplant (AMP) practice mode.

Question bank updated 2026-09-22

QUESTIONA fire extinguisher container's gauge pressure, read at the existing ambient temperature, does not fall within the limits of the pressure-temperature graph. What action is required?

  1. AReplace the extinguisher container
  2. BRecharge the container with nitrogen to the gauge maximum
  3. CDischarge the container and reinstall it after a leak check
Show the answer and explanation

Correct answer: A. Replace the extinguisher container

  • A — correct If the pressure does not fall within the graph limits, the extinguisher container is replaced.
  • B — incorrect Field topping-off is not the prescribed action; the container is replaced when its pressure is outside the published limits.
  • C — incorrect Deliberately discharging and reinstalling the container is not the prescribed corrective action for an out-of-limits pressure reading.

BACKGROUND

Regular maintenance of fire extinguisher systems includes inspecting and servicing the containers, removing and reinstalling cartridges and discharge valves, testing discharge tubing for leakage, and checking electrical wiring continuity. Containers are checked periodically to confirm that pressure is between the prescribed minimum and maximum limits. Because the pressure of the stored agent and its nitrogen charge varies with ambient temperature, changes of pressure with temperature must also fall within prescribed limits, which are published as a pressure-temperature curve showing maximum and minimum gauge readings. If the reading does not fall within those graph limits, the container is replaced. Each container also has a temperature/pressure sensitive safety relief diaphragm that prevents pressure from exceeding container test pressure if the container is exposed to excessive heat.

STUDY TIP

Never read a bottle gauge without also reading the ambient temperature; the pass/fail band moves with temperature. An out-of-band reading means replacement, not servicing in place.

KEY POINTS

  • Container pressure must fall between prescribed minimum and maximum limits for the current temperature.
  • The limits are published as a pressure-temperature graph of maximum and minimum gauge readings.
  • A container whose pressure is outside the graph limits is replaced.

SOURCES

  • sources/amp-powerplant/ch09.txt "Fire Extinguisher System Maintenance Practices"
  • sources/amp-powerplant/ch09.txt "Containers"
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SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-32B Aviation Maintenance Technician Handbook – Powerplant, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.