...re. Airserv's own pilots, just ask yourself what calibre of pilot would be doing this work for half the salary they can get back home unless there was some reason why they can't get such a decent job back home ?
(And no, it's not because of 'the calling'; they bitch worse than anyone if they think they aren't getting the S&T that so-and-so is getting on a similar contract.)
Also, check out the reality of AirServ's apparently perfect safety record (yeah, right) and see the type of pilot - AirServ or Contractor - who was flying in the vast majority of cases....
As for :
'Doesn't it take some time to get a new pilot up to speed for that type (of) work ?'
for SA pilots it's business as usual: dirt strips and incomprehensible ATC, negligible navaids and the worst weather in the world, but for the generally North American or European AirServ pilots, oh yes, as they wet their pants when they can't get radar vectors and an ILS approach.