Pilots with WestJet Encore are gearing up to bargain their second collective agreement.

The Air Line Pilots Association says it's filed notice to open contract negotiations with the regional carrier for WestJet. 

The association says WestJet Encore needs to give its nearly 400 pilots drastic improvements on wages, career progression and more to keep them.

It says management has been unwilling to address pilots' main concerns despite what it calls a mass exodus from their ranks so far this year. 

Earlier this year, WestJet acquired Sunwing Airlines, announced it would be shuttering its discount subsidiary Swoop, and then announced it was merging Sunwing with its mainline business. 

In May, WestJet narrowly avoided a long-weekend pilots strike after it reached a last-minute deal with its mainline and Swoop pilots.