long call is 12 hrs yeah, CDO is a highspeed. ie fly somewhere at 9:15pm, land 10pm, you go to the hotel and have a 5:15am van or something for a 5:30am show for a 6:15am flight that gets you back home at 7am. Basically you don't get the 10 hours of minimum 117 rest, so you never go "off duty", they keep you on duty overnight. They aren't super fun but they have their upsides. Especially if you're good at naps. You are also limited in how many you can do in a row. They also vary greatly in quality, some of them aren't so bad, some I feel are pretty ugly. The april CDO line there was MOT turns out of MSP but it can change month to month in the bid packet. Sometimes people will continue to sit reserve instead of bidding for CDOs if it doesn't work for their situation, so they can go very junior.