ACS codes · Airframe · Water and Waste Systems
AM.II.O.K3 · Knowledge
Inspection and servicing requirements for water and waste systems
Updated October 25, 2026 · element text from the FAA Aviation Mechanic ACS (FAA-S-ACS-1)
Practice AM.II.O.K3 out loud, free
What the ACS says
Inspection and servicing requirements for water and waste systems.
A related practice question from DMEReady
“How does a closed lavatory waste water system differ from an open system?”
Study source: FAA Advisory Circular AC 25.1455-1, chapter n/a — single advisory circular excerpt, page 1
If this code is on your test report
Your Airman Knowledge Test Report (AKTR) lists an ACS code for every knowledge area you missed on the written test. On the A&P oral, each of those codes adds one question to that section, on top of a minimum of four random questions (FAA Mechanic Test Generator FAQ). So if AM.II.O.K3 is on your AKTR, expect the examiner to ask about it. More on how codes turn into oral questions: A&P ACS codes: know your codes before the oral.
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