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Lubrication Systems: Powerplant practice questions

Five original questions on lubrication systems, each with the answer, an explanation and an FAA-H-8083-32B page reference.

1. An oil that flows freely is said to have what?
  1. Low viscosity
  2. High viscosity
  3. High volatility
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A. Low viscosity Oil that flows slowly is viscous, or has high viscosity; viscosity changes with temperature.

Reference: FAA-H-8083-32B, Ch. 6, p. 6-2

2. Where does a wet-sump system store its oil?
  1. In a separate external tank
  2. In a reservoir inside the engine
  3. In the propeller hub
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B. In a reservoir inside the engine A dry-sump engine pumps oil out to a separate tank.

Reference: FAA-H-8083-32B, Ch. 6, p. 6-4

3. In a turbine oil system, which component separates oil from the breather air?
  1. Deoiler
  2. Magnetic chip detector
  3. Fuel-oil cooler
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A. Deoiler An impeller throws the oil outward by centrifugal force; the lighter air passes through the center and is vented overboard.

Reference: FAA-H-8083-32B, Ch. 6, p. 6-28

4. On aircraft with oil-controlled propellers, why may the oil tank outlet be a standpipe?
  1. To keep a reserve oil supply for propeller feathering
  2. To increase oil pressure
  3. To cool the oil
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A. To keep a reserve oil supply for propeller feathering If the engine fails, oil is still available to feather the propeller.

Reference: FAA-H-8083-32B, Ch. 6, p. 6-6

5. On dry-sump radial engines, the check valve that prevents oil draining into the engine when stopped is spring loaded to about what?
  1. 1 to 3 psi
  2. 10 to 15 psi
  3. 50 psi
Show answer

A. 1 to 3 psi It keeps gravity-fed oil from settling in the lower cylinders.

Reference: FAA-H-8083-32B, Ch. 6, p. 6-7

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What does the Powerplant test cover on lubrication systems?

The Aviation Mechanic Powerplant ACS lists lubrication systems as one of its areas. The FAA reference for this material is FAA-H-8083-32B.