Aircraft Electricals

Question 1

For structural protection what must be done reguarding lightning protection?

Answer 1

All necessary and know types of lightning protection must be used

Question 2

What is the basic protection on the aircraft’s structure provided by?

Answer 2

External metal structure

Question 3

What types of protection are typically used for the aircraft structure?

Answer 3

Metallic paint,conductive mesh,coating used

Question 4

What must be done in the event of an aircraft being hit by lightning?

Answer 4

-general walk around dome to find areas of strike and discharge
-find signs of damage through detailed inspection
-severity assessment done

Question 5

What are the two types of damage after a lightning strike?

Answer 5

Direct and indirect

Question 6

Define direct and indirect damage after a lightning strike?

Answer 6

Direct dmg=surface burns,melts,metallic distortion

Indirect dmg=damage to electrical system & equipment caused by large electrical transients on the wiring

Question 7

What must be done if a lightning strike causes a system malfunction?

Answer 7

Full inspection of defective system is necessary

Question 8

What must be done if a lightning strike causes a system malfunction?

Answer 8

Full inspection of defective system is necessary

Question 9

What is the avg lightning strike diameter?

Answer 9

3mm

Question 10

What is the diameter of a high intensity lightning strike?

Answer 10

6mm or above

Question 11

Name 3 areas examined during lightning strike?

Answer 11

-external surfaces
-static discharges
-fuel system valves
-IDG & related wires
-radio systems
-navigation systems

Question 12

What are the 3 common areas hit during a lightning strike?

Answer 12

-fuselage nose section
-trailing edges
-extremities of wings & stabilisers

Question 13

What can happen to components after lightning strike?

Answer 13

They may become lightning strikes

Question 14

What areas may experience internal damage following a lightning strike?

Answer 14

-electrical power systems
-external light wiring
-fuel valves
-generators
-power feeders
-electrical distribution systems

Question 15

Define bonding?

Answer 15

Act of joining g 2 electrical conductors together

Question 16

Define grounding?

Answer 16

Connecting objects to conductive structure or other conductive parts to safely complete either a normal or fault circuit

Question 17

What does bonding allow for?

Answer 17

Equals electrical potentials

Question 18

Name 2 reasons for bonding?

Answer 18

-minimise radio & radar interface
-eliminates fire hazards by preventing sparks between metallic components
-minimises damage to aircraft and passengers from lightning strikes
-provides a low resistance return path for single wire electrical systems
-aids shielding effectiveness

Question 19

What is used as a conductor for current returns and for single wire electrical systems?

Answer 19

The aircraft’s metallic structure

Question 20

What are the 3 grounding conditions?

Answer 20

-grounding must be seperated (AC,DC & shields)
-no more than 4 terminals on 1 stud
-dual grounds must be installed in fuel vapour areas

Question 21

How do you ground composites?

Answer 21

Ground plate integrated into airframe by bonding aluminium wire mesh into composite structure

Question 22

Do composites have high or low electrical resistance?

Answer 22

Composites

Question 23

Name the two bonding types and what they are?

Answer 23

Direct = done by exposing mesh(ground plate) & mounting the equipment directly on conductive path

Indirect = exposing mesh & installing a bonding wire & connector