If on reserve at home, you may be required to report to the airport to remain on standby for possible flight assignment. At Mainline you will not be assigned airport standby duty more than twice in one month unless all other reserves at your base have been required to report for standby duty twice as well (see Article B8.20.02 of the Collective Agreement). If you are assigned a third airport standby while still at home, speak with the crew scheduler and inquire as to whether or not all reserve members at your base have been assigned two airport standby periods in the month. If not, advise them of the above article and clarify that you should not be working a third until all reserve members at your base have been assigned two for the month.
Rouge has different language which states:
L55.14.10.02 An Employee will not be required to report for airport standby more than three (3) times in any block month. An employee may exceed this limitation on a voluntary basis.
In contrast, if you are already at the airport because you are assigned to operate a pairing and are then placed on airport standby because you are no longer required for that pairing (i.e. cancellation), that airport standby does NOT count towards your two per month.
In the case that the crew scheduler is not receptive when you speak to them, accept the assignment, and contact your Local Union office immediately. Inform them of the situation, that you brought Article B8.20.02 or L55.14.10.02 (Rouge) to their attention, and they still did not remove the third airport standby assignment.