Dublin is place where you need one, and where there are limited alternate routes due to the mountains and restricted airspace to the South and the airport to the North.
I found this out one day in a borrowed 152 from which the owner had removed the xpndr for some tlc. Dublin let me in anyway but I wouldn't recommend being half way across the sea before you get clearance!
Presumably special permission could be obtained in advance by phone, but I wonder if they would allow a direct routeing.
Last edited by david viewing; 22nd Oct 2004 at 12:47.