Some things were not meant to fly.
Had a B767 F/O (who had obtained his cpl in a western country) the other day doing his first annual proficency check in the simulator after being checked out.
He was asked to do the take off performance calculations.
Runway 18 in use, wind 240degrees at 10knots.
Calculations were done, but he based them on a 5knot tailwind.
It took 10 minutes to convince him the wind blew "from" and not "to"
Needless to say extra training was recommended.