A link, not a login.
The crew get a link. No account, no password, no IT ticket, no licence. It opens the schedule, the rundown, the chat and the production details on the phone already in their pocket, and installs to the home screen without an app store. Designed at 390 px first, not shrunk to it afterwards.
The link is the credential. It can be revoked for one person or a whole department the moment somebody leaves, and it expires on its own thirty days after the production wraps.
Their own call,
not the department’s.
A rigger reads their own arrival and departure times and the blocks of the day around them. When their own dates differ from the department’s, the screen says so rather than quietly showing one of the two. A change to a call time arrives as a push notification, at the lead time the producer set for that production.
A private layer for every department.
A team leader writes notes straight onto the rundown segments — lighting snapshots, audio scene recalls, vision config, what the floor has to have ready for the next item. Their crew reads them. The producer, the show directors and the other departments read nothing, and that is enforced in the database rather than in the interface.
A note belongs to the segment, not to its position, so it travels when the order changes. On air the crew sees three at once: what is on, what is next, and what follows — the lighting operator reads the next snapshot while the current one is still up.

Channels that already know who belongs in them.
Nobody creates a channel. A department gets one the moment it exists, the producer gets a ring with every team lead in it, and membership follows the roster. There is no parallel set of groups to keep in step with reality.
Department channels are private from the producer and the show directors, deliberately: what a department says to itself belongs to that department. Announcements run the other way — the producer posts once and it lands in every channel, the private ones included, one-way, so replies stay where they belong.

One tap to the person who knows.
Venue, producer and team lead on one screen, each with a call and an e-mail button. A runner who needs an answer in the dark does not go looking for a phone number in a message thread from three weeks ago.