50,000 euros, jesus h christ!
There is no type rating on earth that costs 50,000 euro - so if it is actually a bond you've signed (as opposed to a bank guarantee or loan or whatever) then I suspect it's not worth the paper it's written on.
Employment courts do not look kindly on contracts with built-in punitive costs to the employee to ensure they don't attempt to leave. Back in medieval times they called that kind of thing 'indentured slavery'.
First thing I'd do, is ask your so called employer for an itemized breakdown of how they spent 50,000 on your type rating qualification. When they fail to provide it (which they will, because the actual cost of jet type ratings to airline customers is more like 12-15,000 euro) then give them the phone number of your lawyer and walk away laughing.
If they admit that the 50,000 is just a figure they made up to try and make money off wannabe pilots, and try and get you for 10,000 euro instead, then give them a few choice newspaper cuttings about how those chinese and eastern european people smuggling gang masters are now spending time in prison in first world countries for signing up prostitutes on exactly the same legal basis as the contract you signed with this 'airline'.
If, on the other hand, you've signed a deal with some dubious loan providers or posted some kind of bank guarantee or something in order to get the job, then you may have a bigger problem on your hands.
To answer your original question, no I've never heard of employers in this country buying out bonds, especially not for low time FO's. Why should they, when people are queueing up to give THEM money
