Can't give you exact figures, but in general wages are comparatively low in Ireland.
Wages are high in Scandinavia, Germany, UK (Southeast and London only). UK has much lower tax than the rest of Europe, although it is also a very expensive place to live in.
My guess would be that if you were to be a line maint Engineer in the UK for a major at LHR or LGW you would be looking at around £17,000 ($USD 25,000). Remember, airlines generally pay quite low compared to other industries, but you would get all the associated benefits (free travel etc).
I used to think the brain is the most fascinating part of my body. But, hey, who is telling me that?