Any advice on this one.

Have a problem with loud squeal on VHF transmission – happens with both VHF sets, but only from the left side. Right side doesn’t happen.

Have done all the suggested things from onlookers, cleaning terminals, etc etc., and it only occurs after engine start.

Use Lightspeed ANR 20G headsets.

Changed the SPA 400 intercom with another identical unit – no avail.

Can’t quite recall when it started. Wondered if the installation of Infinity grips in March might have introduced it with a wiring problem – this was done by a avionics technician.

Switching off the intercom and it goes away.

It is quite loud.

Any final suggestions?

Dom Crain

VH-CZJ