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Class I low flash point solvents

Aviation Mechanic General (AMG) practice question 23 of 31 on Cleaning and Corrosion Control. ACS element AM.I.G.R4 · difficulty: standard. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONA mechanic proposes to clean aircraft cabin upholstery with a solvent that has a flash point of 90 °F. How does the handbook classify this solvent?

  1. AA high flash point solvent that is acceptable when adequate ventilation is provided
  2. BA Class I flammable liquid that is not to be used for aircraft cleaning
  3. CA nonflammable agent, since the flash point is above room temperature
Show the answer and explanation

Correct answer: B. A Class I flammable liquid that is not to be used for aircraft cleaning

  • A — incorrect High flash point solvents are those with flash points from 100 °F to 140 °F; 90 °F is below that range and ventilation does not change the classification.
  • B — correct Class I flammable liquids, those with a flash point below 100 °F, are not to be used for aircraft cleaning or refurbishing; a 90 °F flash point falls in that class.
  • C — incorrect A liquid with a flash point of 90 °F is flammable; nonflammable cabin cleaning agents are water-based products or chlorinated dry cleaning agents, not low flash point solvents.

BACKGROUND

The handbook separates cabin cleaning agents into nonflammable types (detergents, alkaline cleaners, acid solutions, deodorizers, mild abrasives, and chlorinated dry cleaning agents) and flammable or combustible types. High flash point solvents such as Stoddard solvent have flash points from 100 °F to 140 °F and fire hazard properties similar to kerosene. Low flash point solvents, Class I flammable liquids with flash points below 100 °F, are not to be used for aircraft cleaning or refurbishing; examples include acetone, aviation gasoline, methyl ethyl ketone, naphtha, and toluol. Where a flammable liquid is absolutely necessary, a high flash point liquid of 100 °F or more is used, and flammable liquids are handled only in approved, labeled containers or safety cans.

STUDY TIP

Fix the 100 °F dividing line in memory and know a few examples on each side of it, such as acetone and MEK (below) versus Stoddard solvent (above).

KEY POINTS

  • Class I flammable liquids: flash point below 100 °F, not used for aircraft cleaning
  • High flash point solvents: 100 °F to 140 °F, fire hazard similar to kerosene
  • Acetone, AVGAS, MEK, naphtha, and toluol are Class I examples

SOURCES

  • FAA-H-8083-30B ch08 "Flammable & Combustible Agents"
Practice the Aviation Mechanic General (AMG) test →Timed 60-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-8083-30B Aviation Maintenance Technician Handbook – General, 14 CFR part 43 and part 65. Regulations and handbooks are revised; confirm details against the current edition.