AMTStandards.orgAviation maintenance

Quick reference

Terms on this page 6

Dotted in the text; open one for its entry, or see the glossary.

Readings in the sources

6 short readings for GEN-D, a topic at a time: what the test asks, and the sections that cover it. Sign in to tick them off as you read.

  1. Aluminum, steel and flexible hose types; AN, MS and AS designations; size by sixteenths; color codes K1, K2, S6

    For the test: Tubing and hose materials, applications, sizes and fittings; material identification

    • FAA-H-8083-30B Ch. 9: Tubing Materials · Aluminum Alloy Tubing · Sizes · Hose Materials & Construction · Fluid Line End Fittings · AN Flared Fittings · MS Flareless Fittings

  2. Cutting, deburring, bending, flaring, flareless connections K3, S1, S2, S8

    For the test: Rigid line fabrication, installation and inspection

    • FAA-H-8083-30B Ch. 9: Rigid Fluid Lines · Tube Cutting · Tube Bending · Tube Flaring · Double Flaring · Flareless Tube Installation · Rigid Tubing Installation and Inspection · Rigid Tubing Inspection & Repair

  3. Hose construction, end fittings, assembly K4, S3, S7

    For the test: Flexible hose fabrication, installation and inspection

    • FAA-H-8083-30B Ch. 9: Flexible Hose Fluid Lines · Hose Fittings · Fabrication & Replacement of Flexible Hose · Installation of Flexible Hose Assemblies · Flexible Hose Inspection · Flexible Hose Testing

  4. Torque values and marking practice K5, K6, R7

    For the test: Torque wrench use on fittings; torque seal and witness techniques

    • FAA-H-8083-30B Ch. 9: Connection & Torque

  5. Clamping, routing, support, minimum bend radius, chafe S4, S5

    For the test: Line and hose inspection; installation and security requirements

    • FAA-H-8083-30B Ch. 9: Clamps · Hose Clamps · Bending

  6. Safety practice, briefly R1–R7

    For the test: System configuration; safety equipment; hazardous fluids; high-pressure systems; a twisted hose; a loosened fitting or displaced hose; tool use while torquing

    • FAA-H-8083-30B Ch. 9: Fluid Line Identification
    • FAA-H-8083-30B Ch. 1: Safety Around Hazardous Materials · Shop Safety

Source: FAA-H-8083-30B, fluid lines and fittings chapter. Public domain. Pointers only.

Chapter and section verified against FAA-H-8083-30B, 2023 edition, on 28 August 2026. Page numbers are deliberately not cited: they move between printings, and a citation that rots silently is worse than a coarser one that stays true. Checked by our handbook citation check against our index of the handbook's chapters and sections.

Element The ACS asks for In the handbook Where in FAA-H-8083-30B What it does not give you
K1, K2, S6 Tubing and hose materials, applications, sizes and fittings; material identification Aluminum, steel and flexible hose types; AN, MS and AS designations; size by sixteenths; color codes Ch. 9 — Tubing Materials; Aluminum Alloy Tubing; Sizes; Hose Materials & Construction; Fluid Line End Fittings; AN Flared Fittings; MS Flareless Fittings —
K3, S1, S2, S8 Rigid line fabrication, installation and inspection Cutting, deburring, bending, flaring, flareless connections Ch. 9 — Rigid Fluid Lines; Tube Cutting; Tube Bending; Tube Flaring; Double Flaring; Flareless Tube Installation; Rigid Tubing Installation and Inspection; Rigid Tubing Inspection & Repair Why a flare seals. GEN-D Concepts §2
K4, S3, S7 Flexible hose fabrication, installation and inspection Hose construction, end fittings, assembly Ch. 9 — Flexible Hose Fluid Lines; Hose Materials & Construction; Hose Fittings; Fabrication & Replacement of Flexible Hose; Installation of Flexible Hose Assemblies; Flexible Hose Inspection; Flexible Hose Testing The lay line, and what it is for. GEN-D Concepts §3
K5, K6, R7 Torque wrench use on fittings; torque seal and witness techniques Torque values and marking practice Ch. 9 — Connection & Torque Why a witness mark exists. GEN-D Concepts §4
S4, S5 Line and hose inspection; installation and security requirements Clamping, routing, support, minimum bend radius, chafe Ch. 9 — Clamps; Hose Clamps; Bending; Rigid Tubing Installation and Inspection —
R1–R7 System configuration; safety equipment; hazardous fluids; high-pressure systems; a twisted hose; a loosened fitting or displaced hose; tool use while torquing Safety practice, briefly Ch. 9 — Fluid Line Identification · Ch. 1 — Safety Around Hazardous Materials; Shop Safety GEN-D Concepts §1 — the risks are the content of this unit

The operative sources

  • The system's maintenance manual for torque values, bend radii, hose part numbers and routing. The handbook's figures are generic; the aircraft's are approved data (GEN-I).
  • The safety data sheet for every fluid in the system — R3.
  • The hose manufacturer's assembly instructions for S7, including cut length, insertion depth and any proof-test requirement.

Two things worth committing to memory
Aviation flares are 37° Automotive and general-industry flares are 45°. They look similar and will not seal against each other
Tube size is the outside diameter in sixteenths of an inch A "dash 6" line is 6/16, or 3/8 in OD

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