In the UK, as a GENERAL rule (there are many rules!), rest must be a minimum of 11 hours (in exceptional circumstances it can be reduced to 10 hours) or as long as the previous duty. A duty will start from when the crew check in at the crew centre, until (normally) 30 mins after chocks on. Normally there is an allowance of around an hour to travel to / from hotels, so we would require a minimum of 10 hours in the hotel (which starts once we are in our rooms), or as long as the previous duty less an hour. If for example I operate LHR
, which is a duty of around 13.5 hours, I would need 13.5 hours between getting back to LHR
, and checking in for my next flight. Some airlines have scheduling agreements which provide more generous rest, but these are the legal minimums. We can do what is called a split duty, where for example, we will operate the last flight of a day to an out station, and then take a short rest (maybe 6 hours), and the operate the first flight of the morning back to base, but this would be counted as just one duty, and the rest period would extend the total available duty period by 1/2 the rest period. For example, if we were able to do a 12 hour duty, and within that we were taking 6 hours rest in a hotel room, the duty could be extended by 6 x 0.5 = 3 hours, making a total of 15 hours. Again total allowable duties are a dark art, and are based on a huge number of factors, some of which are the time that the duty started (duties starting before 6am are shorter), how many sectors are being flown, how many early/late duties have been carried out before, how many time zones you're flying through and whether you have adjusted to local time. It gets even more confusing when the rest of the crew aren't operating the same trip as you, so you have to keep a very close eye on what hours you are working as ultimately the CAA hold you, not the company responsible for complying with flight time limitations.