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Hazard of excessive cooling agent in a tailpipe

Aviation Mechanic Powerplant (AMP) practice question 1 of 7 on Engine Fire Protection Systems. ACS element AM.III.E.R1 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Powerplant (AMP) practice mode.

Question bank updated 2026-09-22

QUESTIONWhy must the amount of CO2 or other cooling extinguishing agent directed into a turbine engine tailpipe be limited?

  1. AThe agent can ignite when it contacts hot metal
  2. BThe turbine housing can shrink onto the turbine
  3. CThe agent leaves a corrosive residue in the tailpipe
Show the answer and explanation

Correct answer: B. The turbine housing can shrink onto the turbine

  • A — incorrect These agents do not support combustion; CO2 is noncombustible and does not react with most substances.
  • B — correct Excessive use of CO2, or other agents that have a cooling effect, can shrink the turbine housing on the turbine and cause the engine to disintegrate.
  • C — incorrect Corrosion is not the stated hazard; Halon 1301 is noncorrosive and CO2 does not react with most substances.

BACKGROUND

Internal tailpipe fires during engine shutdown or false starts can often be blown out by motoring the engine with the starter, and a running engine can be accelerated to rated speed to achieve the same result. If the fire persists, a fire extinguishing agent can be directed into the tailpipe. Carbon dioxide is an effective agent and is widely available on the ramp for fires on the exterior of an aircraft, such as engine or auxiliary power unit fires. However, CO2 absorbs a great deal of heat as it vaporizes, and excessive use of CO2 or other cooling agents can shrink the turbine housing onto the turbine and cause the engine to disintegrate. Many aircraft also provide spring-loaded or pop-out access doors for rapid access to the compressor, tailpipe, or burner compartments.

STUDY TIP

Learn the ground fire sequence in order: motor the engine first, and use agent only if the fire persists. The danger of over-applying a cooling agent is mechanical, not chemical.

KEY POINTS

  • A tailpipe fire during shutdown or a false start is first attacked by motoring the engine with the starter.
  • Agent is directed into the tailpipe only if the fire persists.
  • Excessive cooling agent can shrink the turbine housing onto the turbine and cause the engine to disintegrate.

SOURCES

  • sources/amp-powerplant/ch09.txt "Turbine Engine Ground Fire Protection"
Practice the Aviation Mechanic Powerplant (AMP) test →Timed 100-question exam, by ACS area, or review your misses. Free.
MORE ON ENGINE FIRE PROTECTION SYSTEMS

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.