We know now that aircraft wiring is split up into sections and that we use disconnect areas to be able to seperate parts of wiring.
These disconnects are seperable by a connector and a receptacle. The wires leading into these connectors and receptacles obviously need contacts to connect one wire to the other and to hold them into the connector or the receptacle.
The contacts that we use are pins and sockets, the pins slide into the sockets creating the connection.
The one on the left is obviously a socket and the one on the right a pin.
The contacts have a engaging end (the end that mates with the other contact) and a crimp barrel (the end that is crimped onto the conductor of a wire).
The crimp barrel has a inspection hole through wich the conductor must be visible, the crimp is made between the inspection hole and the end of the crimp barrel so the hole is used to check if the conductor is inserted deep enough into the crimp barrel.
There are two main types of pins and sockets, there are the front release and the rear release, the front release contacts are removed from a connector by using a extracting tool wich is inserted into the connector from the front and 'push' the pin or socket out the back of the connector.
The other type is the rear release, to remove this type we insert a removal tool in the back of the connector and pull the contact out.
The pin and socket in the above picture are both 'front release' type, the extractor is pushed in from the front, releasing the locks that hold the contact in place and then a push out rod pushes the contact out the back of the connector/receptacle.
Here's a view of a front release extractor tool.
To insert the contact back into a connector or receptacle we use a insert tool, for the red front release type contacts we use this tool.
The rear release contacts are removed by inserting a rear release extractor tool from the back of the connector/receptacle and pulling the contact out the back.
As u can see, these are the two main different types of contacts and the connector and receptacle have to be either front or rear release to hold them.
The left socket is a rear release and the right is a front release.
When the locks are disengaged u can push the 'push out' rod to get the contact out.
There are a lot of different pins and sockets available, they come in all kinds of diffent shapes, lengths, thicknesses, wire gauge sizes, materials, etc. etc.
The contacts have a certain diameter size to fit in the holes of the connector/receptacle, these diameter sizes are standard and follow the same thickness measurement as wires do, 'american wire gauge' (AWG), this size is usually referred to as the 'engaging end' of the contact. The other end of the contact is referred to as the 'crimp barrel'.
Obviously, the size of the contact (and therefore the size of the holes in the connector/receptacle) decides wich contact removal and insert tool we must use for that contact. The removal and insert tools are color coded for size.
for AWG 12 we use a yellow tool
for AWG 16 we use a blue tool
for AWG 20 we use a red tool
For more information about wire sizes and contact and crimptool partnumbers see pins and sockets
Here's a view of removing a 'red' size rear release contact. The white part is the removal tool and the color coded part the insert tool (in this case 'size red')
By pushing the rear release tool over the back of the contact, the locks are disengaged.
When the locks are disengaged u can pull the contact out.
To insert this contact back into a connector or receptacle we use the red insert tool.
The insert tool is color coded for size and type.
Different color codes are for different sizes and types.
The front release insert and extracts are also color coded.
For unwired front release contacts (unwired contacts are installed to seal the empty holes but have no wire crimped to it) we can use the front release tool to simply push the contacts out but in the case of a unwired rear release contact removing the contact can be difficult.
In the case of a disconnected connector we can push the rear release removal tool in the back, unlocking the contact and then push on the other side with a needle or a small pin to get the contact out but in the case of a terminal block or a connector with no access we can use a unwired contact removal tool.
Pins and sockets come in many shapes and sizes and are a big part of the avionics profession.