FAA Aviation Mechanic General (AMG)Ground Operations and ServicingHard
A technician is washing an aircraft that has magnesium alloy wheels and aluminum skin panels. Which type of cleaning solution should be avoided to prevent accelerated corrosion of these materials?
- AMild pH-neutral aircraft wash soap
- BAircraft-approved corrosion-inhibiting compound
- CStrong alkaline (caustic) cleaning solutions
- DClean water rinse
Show answer & explanationAnswer & explanation
Correct answer: C. Strong alkaline (caustic) cleaning solutions
Strong alkaline or caustic cleaners aggressively attack magnesium and aluminum alloys, accelerating corrosion and pitting; only mild, pH-neutral, manufacturer-approved cleaning agents should be used on these metals.
Why the other options are wrong
- A. Mild pH-neutral soap is the correct, safe choice for general washing.
- B. Approved corrosion inhibitors are applied to protect, not damage, these metals.
- D. A clean water rinse is a normal and necessary final step, not a hazard.
Corrosion-Safe Aircraft Cleaning
Guidelines for selecting cleaning agents that will not chemically attack aircraft metals such as magnesium and aluminum.
- Avoid alkaline/caustic cleaners on Mg/Al alloys
- Use mild pH-neutral soap for general washing
- Apply corrosion inhibitor after drying bare metal areas
Memory trick: Alkaline + Magnesium = angry metal that corrodes fast.