Combination of a few factors but last I heard it's not a lottery like AC. Your seniority number used to be a number of points.
Chief pilot for some company used to be the highest ranking, you get a certain amount of points for each 1000h jet time, for each 1000h mpic turbine turbine, for your TT. There might be a few other things you could grab some points from. Basically the idea is to reward the most experienced pilots coming in by awarding them the highest seniority spots for each GS. Hope it helps.
Any TS folks on here please weigh in to confirm.

This is to sort out the seniority within a group of pilots hired on the same class. They use a table that attribute points according to :
Jet or Turboprop time under 12.5
Jet or Turboprop time over 12.5 but under 44.0000
Then other points for jets or turboprop over 44,000lbs but under 100,000 lbs
Then again the same for jet or turboprop over 100,000 lbs
Within each of the above groups, some extra points for Captains, less for SIC.
Finally extra points for Chief pilot or Supervisor experience.

Sorry for DC-3, C-46, DC-4 or DC-6 captains and F/Os. That seems to be as good as Cessna 172 time to AT for attributing seniority when you are hired.....

So when do Transat decide your seniority number? On day 1? Do they assign your type also that day?

B07

Your type is assigned before you even show up, your seniority number is assigned a week or two after you start.

What has been course bid so far? B737/A310 only or has there been some B737/A330 also?

B07

Both

Does anybody know what is the course bid for April? Is there any dual type or only B737? Is it only B737/A310 or is there any A330?

B07

Is there any update to the hiring situation with Transat? Are all the ground school classes finished?