Mystery aircraft

I have googled and searched the FAA for this tail number, but it does not seem to exist.

Can anyone of the experts here enlighten me please?

Country: Portugal
Call Sign: Fraction

Assuming it is a Portuguese registered aircraft, this flight could be either CS-DSB or CS-TLY

Sources: … /3-1-N.htm

Thanks Damiross

I got as far as finding out it was Netjets Europe, but drew a blank after that.

I wonder why they did not use the tail ident of the aircraft?

In the USA they use the digits in the registration. European registrations. for the most part are all letters. (One exception is test registrations used in the UK.) You don’t usually see all letters call signs.

Proving run? Those JAR-OPS are a real PIA for new types