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Cooling air for electronics equipment bays

Aviation Mechanic Airframe (AMA) practice question 3 of 15 on Environmental Systems. ACS element AM.II.G.K3 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Airframe (AMA) practice mode.

Question bank updated 2026-09-22

QUESTIONOn most pressurized aircraft, where does the cooling air circulated through the electronics equipment bays come from?

  1. ADrawn directly from the bleed air manifold
  2. BSupplied by the cabin outflow valve
  3. CDucted from the air distribution system
Show the answer and explanation

Correct answer: C. Ducted from the air distribution system

  • A — incorrect The pneumatic manifold supplies the air conditioning packs; equipment bay cooling air is taken from the conditioned air distribution ducting instead.
  • B — incorrect Outflow valves near the aft pressure bulkhead are where cabin air leaves the pressure vessel, so they are an exit rather than a source of cooling air.
  • C — correct The air distribution system makes provisions for ducting and circulating cooling air to the electronics equipment bays.

BACKGROUND

Cabin air on a pressurized aircraft is managed by ducts leading from the pressurization source into and throughout the cabin. Air is usually released from ceiling vents, flows out floor-level vents, passes aft through baggage compartments and under the floor, and leaves through outflow valves near the aft pressure bulkhead. The air distribution system on most aircraft also makes provisions for ducting and circulating cooling air to electronics equipment bays. The same system contains the gasper air system, which takes air from the cold air manifold or duct to an adjustable overhead nozzle at each passenger station. In line fans, jet pumps, temperature sensors, overheat switches and check valves are all parts of the distribution system.

STUDY TIP

Group equipment bay cooling and gasper air together in your mind: both are branches taken off the aircraft's conditioned air distribution ducting. Knowing where a duct draws from makes distribution system questions straightforward.

KEY POINTS

  • Electronics equipment bay cooling air is ducted from the air distribution system.
  • Gasper air is taken from the cold air manifold to overhead nozzles.
  • In line fans and jet pumps boost flow in selected areas of the distribution system.

SOURCES

  • sources/ama-airframe/ch16.txt "Air Distribution"
Practice the Aviation Mechanic Airframe (AMA) test →Timed 100-question exam, by ACS area, or review your misses. Free.
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SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-31B Aviation Maintenance Technician Handbook – Airframe, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.