Originally Posted by
yyz_atc_qq
For what it's worth, there are only 2 routes where the crews work through to Europe, therefore only 2 routes that have this potential with a delay at origin. YYZ-YYT-LHR, and YYZ-YHZ-LHR.
No pilot crew base in YYC, my home airport. They usually deadhead in from YVR (YVR-YYC-LHR / YVR-YYC-FRA).
Also YYZ/YUL-YOW-FRA and YYZ/YUL-YOW-LHR.