Bouraq (RIP) used to have Stdby & Res... Stdby would get notice the day before for morning, or in the morning for afternoon duty. They're also on call to replace reserves should the Res get called up. Res isn't a good thing to do, 6hrs sitting at the airport and you get paid the equivalent of 1hr return flight. Duty limitations apply but to the max limit, not normal limit (14hrs + crew elect + after 3hrs res, max was IIRC 4 cycles and 6hrs + crew elect) instead of (12hrs planned, 14 max then crew elect and 6 cycles and 9hrs and crew elect). Though Ops was known to have been lost in the calculations that the crew just didn't bother except for applying normal duty and duty extensions.
This allows the crew to make very late calls on getting sick (useful for morning rosters)
Sriwijaya had Stdby, OFF
and D/O but no RES... stdby is on call, OFF
is scheduled day off subject to revision (and the 7 day limit and resched to keep those limits), and D/O is total day off (normally due to 7 day limits). The problem was in the end, D/O and OFF
was merged and OFF
revisions have to be made before end of business day the day before. This doesn't give much leeway on the timing of crew calling sick for morning rosters.
But this is better than Lion Air at the moment, which is currently on "pepetual standby" for some strange reasons. The CEO's receiving a lot of letters and emails from the wives of pilots regarding this! *grin*