Soldering And EWIS Installation Flashcards
(48 cards)
What are the two types of solder?
Tin lead alloy
Silver
When would silver solder be used?
Where stronger joins are required
What would tin lead alloy solder be used for?
Lower soldering temperatures, usually for electrical or electronic joints
What is a flux and is it always needed in addition to the solder when soldering?
A flux is used to remove oxide from the contact surfaces and to promote good solder flow.
No, in most cases a flux is built into the solder itself
What are the recommendations for soldering concerning the contacts?
Arrange contacts so solder bucket is facing upwards
Clean contacts with spirit, let them dry
Place tip of iron below contact and place conductor into the bucket
What are the soldering recommendations concerning dry joints?
Hold conductor in place- movement causes dry joints
Check for a shiny appearance- dull is dry joint
What are some other misc. recommendations for soldering?
Flow solder into bucket until level is correct
Check as possible that solder has flowed into conductor
Ensure no strands are outside the bucket
Ensure no excess solder is on outside of bucket
What should be done if a dry joint occurs and why?
Remake it
Dry joints have a high resistance and are fragile
What is a solder sleeve pigtail a common method for?
Attaching a shield ground wire to a shielded cable
What is included on the sleeve of a pigtail?
Two Sealing rings on either end and a band of solder in the middle
What preparation is required for solder sleeve pigtails?
Ground wire and cable shield are stripped to the correct length
How is the pigtail installed?
Positioned with the solder band over the stripped areas of the wire and cable
Heat gun is used to shrink, seal and flow the solder in the pigtail to create the electrical join and a good pigtail.
What should be looked for when inspecting pigtails?
Discolouration- only acceptable if solder can be inspected and if sleeve has not split
Seal rings created an environmental seal
Solder band has fully melted around wire and shield braid
What range does a wire failures impact have
Minor inconveniences to major catastrophes
Why has wiring been made a critical safety of flight system?
Increasing complexity
High density
Critical interference between electrical and electronic systems
What changes the question of if a wire will fail to when it will fail?
Effects of aeging
What approach is required for dealing with wires?
A proactive approach to mitigate the problems caused by faulty wiring, and detecting the issues before they occur.
What could indicate wiring problems?
Un-commanded inputs
Transient or intermittent failures
CND write ups
Ticking faults
What could be the cause of wires failing?
Age
Poor maintenance
Material properties
Exposure (elements, dangerous solutions, etc.)
What are the main conductors in wires?
Copper
Copper alloy
Aluminium
What plate coatings are typically used for wires?
Silver or nickel
What type of material is used for insulation?
Dielectric
How could polyvinyl chloride insulation be identified and what are its issues?
Identified by being thick and heavy
Easily chafes, highly flammable, produces dangerous amounts of smoke when burnt
Why was Kapton better than polyvinyl chloride?
Lighter, thinner, better dielectric properties?
