How a flight goes from a line on a network plan to an aircraft at a gate — network planning, scheduling, fleet assignment, slots, publication, and day-of-ops — and where schedule data ties it all together.
A flight doesn’t appear fully formed. It travels a long road — from a strategic bet about a market, through months of refinement, to an aircraft pushing back from a gate. Understanding that road, and where schedule data flows along it, makes it obvious why the humble SSIM file sits at the centre of so much.
The path from strategy to operation runs roughly like this:
It’s genuinely a cycle: what happens on the day, and how the last season performed, informs the next round of network planning.
| Stage | Owned by | Key output |
|---|---|---|
| Network planning | Network / commercial | Route network + capacity plan |
| Schedule development | Scheduling | The timetable + rotations |
| Fleet assignment | Scheduling / fleet | Aircraft-to-flight assignment |
| Slot coordination | Slot team | Held slots reconciled to schedule |
| Publication | Scheduling / IT | Published SSIM feed |
| Maintenance | Scheduling / ops | SSM / ASM change stream |
| Day of operations | OCC | The operated schedule |
Notice the connective tissue running down the right-hand column: nearly every stage produces, consumes, or modifies schedule data. The network plan becomes a timetable becomes a published file becomes a stream of changes becomes the operated day — and each hand-off is a place the data has to stay faithful.
Because the cycle spans so many teams and systems, the failures tend to happen at the seams:
Every one of these is a schedule-data problem: reading a feed correctly, comparing two versions, checking one dataset against another.
The planning cycle is a relay race, and schedule data is the baton. Drop it at a hand-off and the whole leg has to be re-run.
The teams that run this cycle smoothly share a trait: they can read, compare, and check schedule data quickly at every seam — not just at publication. Open the feed fast, validate against the standard, analyse the whole network, and check it against slot pressure. That’s the foundation SSIM Toolkit is built to provide: one fast, local, deterministic place to work with the schedule at every stage of its life, so the baton never gets dropped.
Next, the failure mode that hides at the seams: deconfliction.
A schedule is a list of flights; an operation is a set of aircraft each flying a connected sequence. Turning one into the other — building rotations and checking they're physically possible — is where the schedule meets reality.
A carrier's network philosophy is written into its schedule — in the banks at its airports, the degree of its stations, and the shape of its route graph. Here's how to read it.
An origin–destination matrix turns a wall of flight legs into a picture of where a network flows. Here's how to read one built from a schedule — and, just as importantly, what it can and can't tell you.
