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Proof test pressure for a repaired flexible hose

Aviation Mechanic General (AMG) practice question 4 of 17 on Fluid Lines and Fittings. ACS element AM.I.D.K3 · difficulty: applied. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONA flexible hose has been repaired using its existing end fittings and new hose material. Before it is installed on an aircraft whose system pressure is 3,000 psi, the handbook recommends testing the hose to at least what pressure?

  1. A3,000 psi, the normal system pressure
  2. B4,500 psi
  3. C6,000 psi
Show the answer and explanation

Correct answer: B. 4,500 psi

  • A — incorrect System pressure is used only for the operational check of a new hose after it is installed in the aircraft; the pre-installation test is at least 1.5 times system pressure.
  • B — correct The handbook recommends testing a hose repaired with existing hardware and new hose material to at least 1.5 times system pressure; 1.5 x 3,000 psi = 4,500 psi.
  • C — incorrect Twice system pressure is not the figure given; the recommendation is at least 1.5 times system pressure, or 4,500 psi here.

BACKGROUND

All flexible hose must be proof-tested after assembly by applying pressure inside the hose assembly. The test medium may be a liquid or gas: hydraulic, fuel and oil lines are generally tested with hydraulic oil or water, while air or instrument lines are tested with dry, oil-free air or nitrogen. When testing with liquid, all trapped air is bled before the cap or plug is tightened, and gas tests are conducted underwater. When a hose has been repaired or overhauled using existing hardware and new hose material, the handbook recommends testing it to at least 1.5 times system pressure before installation, typically on a hydraulic hose burst test stand. A new hose can be operationally checked after installation using system pressure. The hose manufacturer's instructions govern the proof-test pressure and fluid for a specific assembly.

STUDY TIP

Multiply the system pressure by 1.5 for a repaired hose; keep this separate from the manufacturer's proof-pressure figures in the hose specification tables.

KEY POINTS

  • A hose repaired with existing hardware and new hose material is tested to at least 1.5 times system pressure.
  • Liquid lines are tested with oil or water; air lines with dry, oil-free air or nitrogen, underwater.
  • A new hose can be operationally checked at system pressure after installation.

SOURCES

  • FAA-H-8083-30B ch09 "Flexible Hose Testing"
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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.