Yes talking about the aviation arm only
Well what makes WHAT THE or anyone else think that it is for sale? Advent International may want the WHOLE of Cobham as it is or indeed they may sell off parts but that is unknown as yet. In fact the deal has not even gone through yet and has a few hurdles to overcome. Not least that the UK government may want a defence contractor to remain with a large UK ownership.
Throw in the Regional operation in order to get out of the B717 contract?
That makes no sense at all. A little history for you. National Jet and Cobham bid for the surveillance contract years ago and NJS won. Cobham then bought NJS to gain that contract and as a side issue gained what became the airline and regional services divisions, which were one originally. Buying a company you have a contract with does not immediately invalidate the contract. Anyway, QF obviously likes having cheap cabin crew and pilots available to fly their 717 aircraft.