ELH

Question 1

What type of wire is prohibited for manned aerospace applications?

Answer 1

Polyvinyl chloride (PVC) insulated wire and cable

PVC is not suitable due to safety and performance concerns in aerospace environments.

Question 2

What are aircraft (ELH) electrical looms and harnesses?

Answer 2

Physical means of connecting (electrically) various aircraft systems

They facilitate the integration of electrical components within the aircraft.

Question 3

Why do we use different types of electrical wiring?

Answer 3

Examples of different types of electrical wiring used in aircraft are:
* unshielded multi-conductor cable
* shielded single conductor cable
* shielded multi-conductor cable
* twisted pair cable
* coaxial cable.

All of which have their own multiple various specifications designed to meet the different
performance requirements and needs of the aircraft/components it is fitted to.

Question 4

What may interconnecting wires be used for?

Answer 4

Passing data from the radar to a weapon system or applying power to aircraft lighting

Interconnecting wires play a crucial role in connecting different systems within aircraft.

Question 5

What is a tie?

Answer 5

A modified clove hitch (square knot) used individually, where required.

Question 6

What is the maximum diameter for wire bundles according to wiring specifications?

Answer 6

2 inches (5 cm)

This specification ensures proper handling and installation of wire bundles.

Question 7

What is the primary function of Slack?

Answer 7

To allow replacement of terminals at least twice

Other functions include

• to permit ease of maintenance
• to prevent mechanical strain on the wires, cables, junctions and supports
• to permit free movement of shock-and-vibration mounted equipment
• to permit shifting of equipment, for purposes of maintenance, while installed on aircraft.

Question 8

What is the minimum bend radius for individual wires?

Answer 8

Ten times the outside diameter of the wire

This ensures that the wire maintains its structural integrity and electrical performance.

Question 9

What is the minimum bend radius for wire bundles?

Answer 9

Ten times the outside diameter of the largest wire in the bundle

This is to prevent damage to the wires within the bundle.

Question 10

What is the minimum bend radius for coaxial cable?

Answer 10

Six times the outside diameter

Bending coaxial cable beyond this radius can lead to signal loss or damage.

Question 11

True or False: It is acceptable to bend coaxial cable to a radius smaller than six times the outside diameter.

Answer 11

False

Bending coaxial cable beyond the specified radius can damage its structure and performance.

Question 12

What is the guideline regarding routing wires in relation to a battery?

Answer 12

Never route any wires below a battery.

Question 13

What should a technician consider regarding the structure an item may be mounted to?

Answer 13

The structure’s material and the requirement for specific attaching hardware.

The material of the structure can influence the choice of hardware to ensure compatibility and safety.

Question 14

Why is the material of the structure important for attaching hardware?

Answer 14

It may determine the requirement for the attaching hardware to be manufactured from a specific material.

Different materials have varying properties that can affect the durability and safety of the mounted item.

Question 15

What is the primary function of terminal boards?

Answer 15

To connect individual electrical wires without a splice or physically joining the ends.

Terminal boards are commonly used in electrical installations for ease of connection and organization.

Question 16

What do terminal boards provide?

Answer 16

Junction points of good electrical conductivity for circuits that are not frequently disconnected

Question 17

What connects electrical wires to terminal boards?

Answer 17

Terminal lugs

Terminal lugs provide a secure connection point for wires to be attached to terminal boards.

Question 18

What is the primary function of terminal lugs?

Answer 18

To terminate electrical wires of different sizes for easy connection and disconnection

Question 19

Extra Question

What is the primary aim of electrical earthing (Grounding) in an aircraft?

Answer 19

To protect the aircraft and personnel from hazards associated with static electricity discharged

Static electricity can cause sparks that may ignite fuel or damage sensitive electronic equipment.

Question 20

What is Static Ground?

Answer 20

An approved ground point with an impedance of less than 10,000 ohms referenced to earth.

Static ground is used to provide a reference point for electrical systems to ensure safety and proper function.

Question 21

What is Power Ground?

Answer 21

An approved ground point with an impedance of less than 10 ohms to the power system neutral.

Power ground is critical for maintaining the stability and safety of electrical systems.

Question 22

What is electrical bonding?

Answer 22

Electrical bonding is used to connect aircraft components to a common point.

The common point places the aircraft components at the same electrical potential.

Question 23

Extra Question

What is the purpose of bonding and grounding components in an aircraft?

Answer 23

To ensure a majority of the aircraft remains at the same potential difference

This is critical for preventing electrical interference and enhancing safety.

Question 24

What is the maximum resistance required across a bonding point or grounding jumper?

Answer 24

0.1 ohms or less

100 Milli Ohms

Question 25

What is the maximum bonding resistance for RF components?

Answer 25

0.0025 ohms | (2.5 Milli ohms) ## Footnote This specification ensures optimal performance and signal integrity for RF applications.

Question 26

Why do we use different types of electrical wiring?

Answer 26

To meet the different performance requirements and needs of the aircraft/components it is fitted to ## Footnote Each type of wiring has multiple specifications tailored for specific functions.

Question 27

What type of cord is used when tying bundles? ## Footnote And why is round cord not used for tying bundles?

Answer 27

A narrow flat-type cord is used ## Footnote Round cord is not used because it can cut into the wire insulation.

Question 28

What does the pre-waxed flat cord provide resistance to?

Answer 28

Moisture and fungus

Question 29

What is the M22520/1-01 **Type 1** crimp tool used for?

Answer 29

Type 1 crimp tools are used to produce an indent crimp ## Footnote Indent crimping creates a mechanical connection between wires and terminals.

Question 30

What should happen when the ‘GO’ end of the gauge is tested? What should happen when the ‘NO GO’ gauge is tested?

Answer 30

The ‘GO’ end of the gauge **should** freely pass through indenters when the tool is in the fully closed position. The ‘NO GO’ gauge **should not** pass through indenters when the tool is in the fully closed position.

Question 31

What action should be taken if gauging fails?

Answer 31

Reject the tool and have it sent for repair or calibration.

Question 32

# Lightning Protection What role does **careful shielding**, **bonding**, the **application of surge supression devices** and the **methods to discharge the static charge** play with regards to **lightning protection** in cables?

Answer 32

Averts problems caused by indirect effects in cables and equipment

Question 33

What are the three methods of discharging static electricity?

Answer 33

* earthing leads * static discharge wicks * null field dischargers

Question 34

What is the M22520/5-01 **Type 2** crimp tool used for?

Answer 34

It is used to produce a formed crimp ## Footnote The crimping process is essential in creating reliable electrical connections.

Question 35

What is the maximum number of splices allowed in a wire segment between two connectors?

Answer 35

There should not be more than one splice in any wire segment between any two connectors ## Footnote This is a guideline to ensure reliability and reduce potential points of failure in electrical connections.

Question 36

With regards to Splicing, what are two main expamples of when splicing is not an applicable option?

Answer 36

* Splices are not to be used **within 12 inches of a termination device** * Splices shall not be used **on firing or control circuits associated with ordinance or explosives**

Question 37

What must be done if there is damage to looms and harnesses associated with the **aircraft's ignition system** or **fire warning system?**

Answer 37

Repair by replacement ## Footnote This indicates that direct repairs are not permitted for these components.

Question 38

What should you not do to the braid, dielectric, and centre conductor when attaching BNC crimp connectors? | Coaxial Cables

Answer 38

Do not nick braid, dielectric and centre conductor ## Footnote Nicking can damage the cable and affect performance.

Question 39

What are three uses of a solder sleeve?

Answer 39

* **connect a cable shield to a ground lead** * terminate a cable * repair or replace the cable shield.

Question 40

What is the primary function of electrical plugs or connectors in aircraft systems? And where are electrical plugs or connectors typically installed?

Answer 40

* The primary function of electrial plugs or connnectors it to **form a link between the component and the aircraft system** * Electrical plugs or connectors are **typically installed on wiring that is frequently disconnected**

Question 41

What does the Test Button on a Megger Meter do?

Answer 41

Applies voltage for measurements ## Footnote The Test Button is typically used in insulation resistance testing.

Question 42

How do you do a Serviceability test of a Megger Meter?

Answer 42

Serviceability of the megger meter is to be carried out by * placing the 2 leads together * placing the dial on the 50 V position * pressing the test button * and ensuring 0.00 ohms is displayed.

Question 43

What is the range we can test circuits do on a Megger Meter?

Answer 43

50V, 100V, 250V, 500V, 1000V

Question 44

What is soldering primarily used for?

Answer 44

Soldering provides a convenient method for making a conductive electrical/electronic connection. This is also easily reversible ## Footnote Soldering is valued for its versatility and reliability in creating connections.

Question 45

What is the most commonly used alloy in the soldering of electronic terminations?

Answer 45

A tin/lead alloy of 60/40 composition That is 60% tin and 40% lead

Question 46

What is wetting action in soldering?

Answer 46

The free flow and spreading of solder to form a uniform, smooth, unbroken and adherent film of solder on a base metal.

Question 47

When is wetting action considered complete?

Answer 47

When all of the desired surface area is covered by solder.

Question 48

How can wetting action be measured?

Answer 48

By the tangent angle at which the solder meets the surfaces of the metals being soldered.

Question 49

What document refers to procedures applicable to wire marking?

Answer 49

AAP 7045.002-1 Sect 2 Ch. 2 ADF Aircraft Wiring and Bonding Manual ## Footnote This manual outlines specific guidelines and standards for marking wires in aircraft applications.

Question 50

How are terminals lugs fitted?

Answer 50

Via "tend to tighten" ## Footnote This characteristic helps ensure a stable connection over time.

Question 51

What is the purpose of bonding and grounding connections in aircraft?

Answer 51

To protect the aircraft and personnel from **electrical hazards** such as **earth leakage** (electric shock) and **lightning protection.**

Question 52

What is bonding?

Answer 52

The **electrical connecting of two or more conducting objects** not otherwise adequately connected.