Brassplate... grow up ! Wow, there is a A320 aircraft grounded with corrosion in an engine pylon.... !! please supply more information...
Ok I do not know the details behind this story but would love to find out more... but from what I know about the A320 engine pylons they are made mostly made from stainless steel and titanium alloys which are very resistant to corrosion but the aft fixed fairing and moveable fairings are made from 2024 aluminium that in this area suffer from corrosion and hydrogen embrittlement due the hot enviroment. If this is the case the corrosion is common for all A320 series aircraft and is not primary structure and your engineer that grounded the aircraft is probably being very cautious and observant and you should thank him.
I have seen VERY serious corrosion in this area that had been overlooked by engineers for many months/years but still on total failure would not have affected the satety of the flight.
If you have so little confidence in your maintenance staff why do you still fly the aircraft??