Namely, how does the INT/RAD switch work? If one wants to speak to the engineer through the interphone, I don't see why you would need the interphone switch. Surely you would just press the MECH transmission button and then select the MECH reception knob.
Well, by keeping the switch in INT position it is a hot mike and the mechanic can hear everything that you say on the intercom. Whereas, by keeping it in neutral position and selecting the INT switch, you can decide what mechanic gets to hear.
What does the INT/RAD button do? How does it work?
On INT mode it is a hot mike and works just like a normal intercom, in the middle is neutral position where neither is selected, when RAD is selected it act as a PTT button, the transmission takes place depending on what you have selected on the ACP.
Also, when one is forced to shut the port engine on the A319 down (so materials on stand aren't sucked into the engine), what is the procedure for the hydraulics? I have heard you have to turn the YELLOW ELEC pump ON, then OFF after Engine 2 shutdown.
If you are
forced to shut down one engine I am sure you'd have more problems than materials being sucked into the engine!! The normal procedure for engine start is to start #2 first and for shutdown is to shutdown #1 first. That way Yellow HYD system is available and that is what powers the parking brakes. If on the triple indicator the ACCUM pressure is low, you can turn the YELLOW ELEC pump ON but with mechanics consent, incase they are working on something down under.