Thinking about the Question 1)
Question 2) - EMI can occur and can be attributed to several causes - poor or degraded screening of cabling in the audio integrating system; poor electrical bonding or degraded connections of/in electrical consumer equipment - particularly reactive devices like electric motors and tacho-generators. Also poor static discharging can also cause problems. I've had to deal with the latter on light aircraft but never on a big one. I've dealt with the other defects on 757s and 737-200s.
Poor comms can also be attributed to problems with antenna feeders and actual antenna installations.
Last edited by Bus429; 22nd March 2004 at 15:51.