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Applying corrosion-preventive mixture before storage

Aviation Mechanic Powerplant (AMP) practice question 9 of 13 on Reciprocating Engines. ACS element AM.III.A.K6 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Powerplant (AMP) practice mode.

Question bank updated 2026-09-22

QUESTIONDuring the final run-in of an engine that will be shipped or stored, how is corrosion-preventive mixture applied to the induction passages and combustion chambers?

  1. AIt is brushed onto the cylinder walls by hand
  2. BIt is drawn into the engine by aspiration
  3. CIt is packed in as a grease at assembly
Show the answer and explanation

Correct answer: B. It is drawn into the engine by aspiration

  • A — incorrect Hand application is not the method described; the mixture is breathed in through the induction system while the engine runs.
  • B — correct The handbook states that the induction passages and combustion chambers are treated with corrosion-preventive mixture by an aspiration method, in which the mixture is drawn or breathed into the engine.
  • C — incorrect The preservative is a mixture of corrosion-preventive compound and engine oil applied at final run-in, not a grease packed in during assembly.

BACKGROUND

After an engine successfully completes its test requirements, it is specially treated to prevent corrosion if it will be shipped or stored before installation in an aircraft. During the final run-in the oil system is serviced with a mixture of corrosion-preventive compound and engine oil, and the temperature of that mixture is maintained at 105 degrees Celsius to 121 degrees Celsius. Near the end of final run-in, corrosion-preventive mixture is used as the engine lubricant. The induction passages and combustion chambers are treated with the same mixture by an aspiration method, meaning the mixture is drawn or breathed into the engine.

STUDY TIP

Remember that preservation happens while the engine is running at the end of run-in, which is why the internal surfaces are reached by aspiration rather than by hand.

KEY POINTS

  • Engines shipped or stored are treated against corrosion after successful testing.
  • Corrosion-preventive mixture is held at 105 to 121 degrees Celsius in the oil system.
  • Induction passages and combustion chambers are treated by aspirating the mixture into the engine.

SOURCES

  • FAA-H-8083-32B ch10 "Testing Reciprocating Engines"
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MORE ON RECIPROCATING ENGINES

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.