If you are looking at the ContractAir contract, then the basic take home after tax works out at about £5000. There are per diems that are paid direct from JetAirFly. Tend to be around the £500 a month. You are PAYE in the UK with Contractair. There is a local tax of about 9%, but that is paid by JAF.
You will offered a service apartment in the Verac Flats. These are about a 10 minute walk from the crew room. They are 'ok' and in the summer are full of crew or engineers from a number of airlines. Personally, I hated the place as it felt like a prison after a while. I would take the allowance they offer instead and find my own apartment for the summer. JAF will give you €1000 a month in lieu of the Verac flats. This can get you something very nice. Especially if you want to live away from Brussels. Mechelen and Leuven would be my choice.
Commuting. No forget it. You will work a full roster through the summer. Typical shifts of 6/3 or 5/2. Finish on a late and start on an early. You have the option of taking your holiday allowance at the end of a 3 day off to make it 4, but this generally only happens about once a month. It is the biggest downside to this contract is that you can't get home easily. If you have a family, consider taking the housing allowance and finding a nice place to live.
The standby system is very 'unique'. You are basically on standby from 6am till 10pm. Early shifts start at 4am, Late shifts can finish past 2am. Its not unknown that you will have a late shift, followed by and day off, then onto an early. How they expect you to get proper sleep is anyones guess.
It's hard graft for the summer, expect 100 hours every 28 days.
- Is it just a summer contract or any chance that it can be full time?
Depends on one very important question. What fleet are you applying for. They are desperately short of E190 drivers and everyone on this fleet was asked to stay on for the winter and next season. The B737 fleet has a much larger pool of pilots, so don't expect to continue during the winter on this fleet.
Good luck, it's actually a nice contract. The crews are all fantastic and the crew food is awesome (if lacking in variety).