11.2 Electrical Bonding

Question 1

What is bonding?

Answer 1

Joining two electrical conductors together

Question 2

What is grounding?

Answer 2

Grounding is the process of electrically connecting conductive objects to either a conductive structure or some other conductive return path to safely complete either a normal or fault circuit

Question 3

How do you ensure the same electrical potential is kept on an aircraft when in flight?

Answer 3

By bonding aircraft components together using conductive pathways to ensure they maintain the same electrical potential

Question 4

What does bonding also provide for single wire electrical systems?

Answer 4

A low resistance return path

Question 5

What are some reasons for bonding?

Answer 5

To minimise radio and radar interference, To eliminate fire hazards by preventing a spark between two metallic components at different potentials, To minimise the damage to the aircraft and its passengers from lightning strikes, To provide a low-resistance return path for single-wire electrical systems, To aid in the effectiveness of the shielding

Question 6

What is the aircraft’s metallic structure used as for single wire electrical systems?

Answer 6

Conductor for current

Question 7

Grounding or earthing is the process of connecting these systems and the shields of shielded cables to the aircraft’s metallic structure at pre-designated points, what are these points used for?

Answer 7

These points can often be used to provide a path to earth or to maintain a common electrical potential between the aircraft and ground equipment and service vehicles

Question 8

What must grounding points be?

Answer 8

Grounds must be separated (AC, DC, and shields), There must be no more than four terminals on one stud, Dual grounds must be installed in fuel-vapour areas

Question 9

Do composites on aircraft have high or low electrical resistance?

Answer 9

High

Question 10

What are composite materials unsuitable for?

Answer 10

Bonding, earth returns and lightning strike dissipation

Question 11

What is direct bonding?

Answer 11

Direct bonding is achieved by exposing the mesh (ground plate) and mounting the equipment directly onto the conductive path

Question 12

What is indirect bonding?

Answer 12

Indirect bonding is achieved by exposing the mesh and installing a bonding wire and connector

Question 13

Must must you do to ensure a low resistance connection when bonding?

Answer 13

Remove non conducting paint and anodising films

Question 14

What is the highest the resistance value can go if resistance bonding is done correctly?

Answer 14

0.025 ohms