Aircraft Electrical Systems

Question 1

1. What is the purpose of a circuit breaker?

Answer 1

To protect the circuits & wires from fire.

Question 2

2. What re the two principles on which circuit breaker operates?

Answer 2

Thermal & magnetic

Question 3

3. What tool is used to measure the size of unmarked electrical wire?

Answer 3

Wire gauge

Question 4

4. What are the colors of aircraft position lights and where are they mounted?

Answer 4

Green light - right wingtip
Red light - left wingtip
White light - visible from rear of aircraft

Question 5

5. What are the factors to be considered when selecting wire size for electrical power?

Answer 5

Allowable power loss
Permissible voltage drop
Current carrying ability of the conductor

Question 6

6. When is a circuit breaker or fuse designed to open the circuit?

Answer 6

Before conductor emits smoke

Question 7

7. What type of breakers are not acceptable for use in aircraft?

Answer 7

Auto reset

Question 8

8. What is a slow-blow fuse?

Answer 8

A fuse that compensates for surges & high inrush current by delaying by a few milliseconds

Question 9

9. What are the three most common faults that occur in an electrical circuit?

Answer 9

Open circuits
Shorted circuits
Low power

Question 10

10. What size electrical conduit should be used for a specific cable bundle?

Answer 10

25% larger than maximum wire bundle

Question 11

11. What color insulator on a solderless connector is proper for a 10 gauge wire?

Answer 11

Yellow

Question 12

12. How should electrical switches typically be oriented in the on position?

Answer 12

Up or forward

Question 13

13. When should electrical switches be de-rated from their normal current rating?

Answer 13

High rush-in circuits
Inductive circuits
DC motor circuits

Question 14

14. When do DC electric motors draw several times their rated current?

Answer 14

During starting

Question 15

15. What would cause an AC electrical motor to run too fast?

Answer 15

Excessive supply of voltage or motor field windings shortened

Question 16

16. What would cause an AC electrical motor to run too slow?

Answer 16

Low voltage
Defective wiring
No lubrication

Question 17

17. How is the output voltage of an alternator controlled?

Answer 17

Voltage regulator

Question 18

18. What should be checked before any aircraft electrical load is increased?

Answer 18

Associated wires
Conductors
Circuit protection devices

Question 19

19. What is the main advantage of using AC for aircraft electrical power systems?

Answer 19

Easily changed using transformers

Question 20

20. In AC power systems, how is DC obtained for battery charging?

Answer 20

Using rectifiers

Question 21

21. What warns pilots of overheating batteries?

Answer 21

Thermal sensor in the battery & light in cockpit

Question 22

22. How long should bonding jumper wires be made?

Answer 22

Large enough to handle return current but short enough to prevent increase in resistance

Question 23

23. How are the two items that wear on start generators?

Answer 23

Commutator & brushes

Question 24

24. What power the ELT?

Answer 24

ELT Battery

Question 25

25. What is the purpose of a static wick?

Answer 25

Dissipates static energy from aircraft to avoid damaging electrical systems