15.8 MCQ

Question 1

1. Main bearing oil seals used with turbine engines are usually what type(s)?.

Option A. Teflon and synthetic rubber.
Option B. Labyrinth and/or carbon rubbing.
Option C. Labyrinth and/or silicone rubber.

Answer 1

Option B. Labyrinth and/or carbon rubbing.

Question 2

2. If, during inspection at engine overhaul, ball or roller bearings are found to have magnetism but otherwise have no defects, they.

Option A. are in an acceptable service condition.
Option B. cannot be used again.
Option C. must be degaussed before use.

Answer 2

Option C. must be degaussed before use.

Question 3

3. A carbon seal has which type of sealing arrangement?.

Option A. Full contact with race.
Option B. Full contact with casing.
Option C. Full contact with labyrinth.

Answer 3

Option A. Full contact with race.

Question 4

4. The highest turbine bearing temperature takes place.

Option A. all the time.
Option B. at start-up.
Option C. at shut-down.

Answer 4

Option C. at shut-down.

Question 5

5. Indentations on bearing races caused by high static loads are known as.

Option A. fretting.
Option B. galling.
Option C. brinelling.

Answer 5

Option C. brinelling.

Question 6

6. The function of a labyrinth seal is to create.

Option A. a restricted leakage of air between fixed and rotating components.
Option B. an airtight seal between fixed and rotation components.
Option C. an airtight seal between fixed adjacent casing surfaces.

Answer 6

Option A. a restricted leakage of air between fixed and rotating components.

Question 7

7. The bearings of a compressor rotor are usually.

Option A. ball and roller.
Option B. plain.
Option C. sintered.
Correct Answer is. ball and roller.

Answer 7

Option A. ball and roller.

Question 8

8. Bearing seal failure would most probably cause.

Option A. high oil temperature.
Option B. high oil consumption.
Option C. low oil pressure.

Answer 8

Option B. high oil consumption

Question 9

9. Why are oil seals pressurised?.

Option A. To ensure minimum oil loss.
Option B. To ensure oil is forced into the bearings.
Option C. To ensure that the oil is prevented from leaving the bearing housing.

Answer 9

Option A. To ensure minimum oil loss.

Question 10

10. What bearing is used to take axial loads on a main rotation shaft of a gas turbine engine?

Option A. Plain bearing.
Option B. Roller bearing.
Option C. Ball bearing.

Answer 10

Option C. Ball bearing.

Question 11

11. Seals on a gas turbine engine restrict leakage of oil by.

Option A. spring pressure.
Option B. closely tolerated contacting components.
Option C. air pressure.

Answer 11

Option C. air pressure.

Question 12

12. An abradable lining in the fan case.

Option A. prevents fan blade tip rub.
Option B. produces less leakage at tips for anti-ice.
Option C. provides acoustic medium.

Answer 12

Option C. provides acoustic medium.

Question 13

13. Squeeze film bearings are usually found on.

Option A. H.P compressor section.
Option B. the turbine section.
Option C. LP compressor section.

Answer 13

Option C. LP compressor section

Question 14

14. Taper roller bearings accept loads in which direction?.

Option A. Axial loads only.
Option B. Radial and axial in both directions.
Option C. Radial and axial in one direction only.

Answer 14

Option C. Radial and axial in one direction only

Question 15

15. Some labyrinth seals.

Option A. control the outflow of air at the turbine.
Option B. are self lubricating.
Option C. are spring loaded.

Answer 15

Option A. control the outflow of air at the turbine.

Question 16

16. The purpose of ‘squeeze film’ type bearing is to.

Option A. increase the flow of oil to the rolling element.
Option B. minimise the effect of vibration.
Option C. improve outer race cooling.

Answer 16

Option B. minimise the effect of vibration.

Question 17

17. In a jet engine the rotating assembly oil seals are maintained oil tight by means of.

Option A. a garter seal.
Option B. an annular expander ring.
Option C. air pressure.

Answer 17

Option C. air pressure.