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Exhaust leaking into the induction system

Aviation Mechanic Powerplant (AMP) practice question 1 of 8 on Engine Exhaust and Reverser Systems. ACS element AM.III.L.R2 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Powerplant (AMP) practice mode.

Question bank updated 2026-09-22

QUESTIONExhaust gases escaping from a failed heat exchanger surface are drawn into the engine induction system. Besides the carbon monoxide hazard, what does this cause?

  1. AA rise in engine oil pressure
  2. BLoss of cabin pressurization and heat
  3. CEngine overheating and power loss
Show the answer and explanation

Correct answer: C. Engine overheating and power loss

  • A — incorrect The stated consequences of exhaust gas reaching the induction system are engine overheating and power loss; an effect on oil pressure is not among them.
  • B — incorrect A heat exchanger surface failure lets exhaust gas escape into the cabin heat system rather than taking heat away, and pressurization is not part of this failure.
  • C — correct Failure of heat exchanger surfaces can permit exhaust gases to be drawn into the engine induction system, causing engine overheating and power loss.

BACKGROUND

Approximately half of all muffler and heat exchanger failures can be traced to cracks or ruptures in the heat exchanger surfaces used for cabin and carburetor heat sources. Failures in the heat exchanger surface, usually in the outer wall, allow exhaust gases to escape directly into the cabin heat system, and in most cases these failures come from thermal and vibration fatigue cracking in areas of stress concentration. Failure of the spot-welds that attach the heat transfer pins can also result in exhaust gas leakage. In addition to the carbon monoxide hazard, failed heat exchanger surfaces can permit exhaust gases to be drawn into the engine induction system, causing engine overheating and power loss. Any exhaust system failure should be regarded as a severe hazard.

STUDY TIP

Learn the two-part consequence of a heat exchanger leak: carbon monoxide into the cabin and exhaust gas into the induction system, which overheats the engine and costs power. Black soot around an exhaust gasket is an early warning.

KEY POINTS

  • Roughly half of muffler and heat exchanger failures are cracks in heat exchanger surfaces.
  • Such a failure sends exhaust into the cabin heat system, creating a carbon monoxide hazard.
  • Exhaust drawn into the induction system causes engine overheating and power loss.

SOURCES

  • sources/amp-powerplant/ch03.txt "Muffler & Heat Exchanger Failures"
Practice the Aviation Mechanic Powerplant (AMP) test →Timed 100-question exam, by ACS area, or review your misses. Free.
MORE ON ENGINE EXHAUST AND REVERSER 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.