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AMA · 7% of the exam

Hydraulic and Pneumatic Systems practice questions

10 free Hydraulic and Pneumatic Systems questions for the Aviation Mechanic Airframe (AMA) Knowledge Test exam, each with the correct answer and an explanation for every option.

Start the questionsFree 10-question AMA quiz

What this domain covers

Hydraulic and pneumatic power systems.

Exam weight
7%
On a real exam
≈ 7 questions
In our bank
40 questions

Topics that come up most

  • Hydraulic fluids
  • Pumps, valves and actuators
  • Accumulators
  • Seals and filters
  • Pneumatic systems

How to study it

Follow fluid through a system diagram; component-function questions become straightforward.

Sample Hydraulic and Pneumatic Systems questions

Try each one before opening the answer. Original questions written to the official exam objectives.

  1. Question 1

    What does a hydraulic actuating cylinder do?

    • AStores fluid
    • BLinear force
    • CFilters fluid
    • DMeasures pressure
    Show answer and explanation

    Answer: B) Linear force

    • AIncorrect. That is a reservoir.
    • BCorrect. It converts fluid pressure into straight-line mechanical force.
    • CIncorrect. That is a filter.
    • DIncorrect. That is a gauge.

  2. Question 2

    Why is MIL-PRF-83282 hydraulic fluid used in some systems designed for MIL-PRF-5606?

    • AIt is a phosphate ester fluid with much better fire resistance
    • BIt is more fire resistant and works with the same seals
    • CIt is a vegetable-based fluid
    • DIt is used only in brakes
    Show answer and explanation

    Answer: B) It is more fire resistant and works with the same seals

    • AIncorrect. Phosphate esters need different seals.
    • BCorrect. It offers better fire resistance with similar seals.
    • CIncorrect. It is synthetic hydrocarbon based.
    • DIncorrect. It is used in whole systems.

  3. Question 3

    What is the main purpose of a hydraulic accumulator?

    • AMeasure fluid quantity
    • BFilter the fluid
    • CCool the fluid
    • DStore pressure
    Show answer and explanation

    Answer: D) Store pressure

    • AIncorrect. Sight gauges do that.
    • BIncorrect. Filters do that.
    • CIncorrect. Heat exchangers do that.
    • DCorrect. Accumulators store pressurized fluid and dampen pressure surges.

  4. Question 4

    A technician is replacing O-rings in a system serviced with phosphate ester (Skydrol-type) hydraulic fluid. Which seal material is compatible with this fluid?

    • ABuna-N (nitrile) synthetic rubber
    • BNeoprene synthetic rubber
    • CNatural gum rubber
    • DButyl or ethylene propylene rubber
    Show answer and explanation

    Answer: D) Butyl or ethylene propylene rubber

    Each hydraulic fluid type needs its own seal material. Phosphate ester fluids use butyl, ethylene propylene or Teflon seals, while petroleum-base MIL-H-5606 uses Buna-N.

    • AIncorrect. Buna-N is the usual seal material for petroleum-base MIL-H-5606 fluid. Phosphate ester fluid attacks it and makes it deteriorate.
    • BIncorrect. Neoprene is used with petroleum-base fluids and is not compatible with phosphate ester fluid.
    • CIncorrect. Natural rubber seals were used with older vegetable-base fluids. They do not hold up in phosphate ester fluid.
    • DCorrect. Butyl rubber, ethylene propylene (EPR) and Teflon seals are specified for phosphate ester fluids such as Skydrol.

  5. Question 5

    Which are common types of hydraulic accumulators?

    • APiston, bladder and diaphragm
    • BGear, vane and piston pumps
    • CCheck, relief and selector types
    • DOnly open reservoirs
    Show answer and explanation

    Answer: A) Piston, bladder and diaphragm

    • ACorrect. All separate gas and fluid.
    • BIncorrect. Those are pump types.
    • CIncorrect. Those are hydraulic valve types, not accumulator types.
    • DIncorrect. Accumulators are pressurized.

  6. Question 6

    What does a variable-displacement hydraulic pump do?

    • AIt is a manual hand pump
    • BIt always delivers the same flow at any system pressure
    • CIt works only on the ground
    • DIt adjusts its output to match system demand
    Show answer and explanation

    Answer: D) It adjusts its output to match system demand

    • AIncorrect. It is engine or motor driven.
    • BIncorrect. That describes a constant-displacement pump.
    • CIncorrect. It works in flight.
    • DCorrect. It reduces flow when demand is low.

  7. Question 7

    Which gas is used to precharge a hydraulic accumulator?

    • AShop air with moisture
    • BOxygen
    • CHydrogen
    • DDry nitrogen
    Show answer and explanation

    Answer: D) Dry nitrogen

    • AIncorrect. Moisture causes corrosion.
    • BIncorrect. Oxygen with hydraulic fluid is a fire hazard.
    • CIncorrect. Hydrogen is flammable.
    • DCorrect. Nitrogen is inert and dry.

  8. Question 8

    Why do some hydraulic systems include a heat exchanger?

    • ATo filter the fluid
    • BTo heat the cabin
    • CTo store fluid
    • DTo cool the fluid
    Show answer and explanation

    Answer: D) To cool the fluid

    • AIncorrect. Filters do that.
    • BIncorrect. This is not the purpose.
    • CIncorrect. Reservoirs do that.
    • DCorrect. Heat exchangers keep fluid within temperature limits.

  9. Question 9

    What is the function of a snubber installed in the line to a hydraulic system pressure gauge?

    • AIt damps pressure surges and pulsations so the gauge needle stays steady and is not damaged
    • BIt keeps fluid in the gauge line from flowing back toward the reservoir when the pump stops
    • CIt opens to relieve excess pressure in the gauge line when system pressure exceeds a set limit
    • DIt shuts off flow to the gauge line automatically if the line ruptures and fluid is lost
    Show answer and explanation

    Answer: A) It damps pressure surges and pulsations so the gauge needle stays steady and is not damaged

    A pressure gauge snubber is a restrictor that damps pressure surges. It keeps the gauge reading steady and protects the gauge mechanism.

    • ACorrect. A snubber is a restrictor that slows pressure changes reaching the gauge. This smooths out pump pulsations and pressure spikes, so the reading is steady and the gauge is protected.
    • BIncorrect. That describes a check valve, which allows flow in only one direction. A snubber restricts flow but does not block reverse flow.
    • CIncorrect. That describes a relief valve, which limits maximum system pressure. A snubber has no pressure setting and does not vent fluid.
    • DIncorrect. That describes a hydraulic fuse, which closes when it senses excessive flow or volume. A snubber only damps fluctuations.

  10. Question 10

    What does a sequence valve do in a hydraulic system?

    • AIt makes one action finish before the next one starts
    • BIt limits the maximum pressure in the system by venting fluid
    • CIt filters the fluid
    • DIt stores fluid under pressure
    Show answer and explanation

    Answer: A) It makes one action finish before the next one starts

    • ACorrect. Sequence valves control the order of actuation.
    • BIncorrect. That is a relief valve.
    • CIncorrect. Filters remove contaminants.
    • DIncorrect. Accumulators store pressure.

Hydraulic and Pneumatic Systems: FAQs

How much of the AMA exam is Hydraulic and Pneumatic Systems?

Hydraulic and Pneumatic Systems is 7% of the AMA exam by the official exam guide's weighting, which on a 100-question form works out to roughly 7 questions. The real exam's exact split varies by form.

What does the Hydraulic and Pneumatic Systems domain cover?

Hydraulic and pneumatic power systems.

How should I study Hydraulic and Pneumatic Systems for AMA?

Follow fluid through a system diagram; component-function questions become straightforward.

Where can I practise more Hydraulic and Pneumatic Systems questions?

This page has 10 free Hydraulic and Pneumatic Systems questions with answers. The ExamWize AMA question bank has 40 questions in this domain. Every practice exam result breaks your score down by domain, and Review Mode re-drills the questions you missed.

Other AMA topics

Also: 15 free questions across all topics, the AMA cheat sheet and the study guide.

Get Hydraulic and Pneumatic Systems exam-ready

The full AMA bank has 40 Hydraulic and Pneumatic Systems questions. Timed practice exams match the real exam's length and domain weights, every result shows your score per domain, and Review Mode re-drills the questions you missed.

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Not affiliated with FAA; questions are original, written from the official exam outline, and never copied from the real exam.