Settings

Day

Day runs —

Worked out from the positions — earliest start to latest finish.

Time granularity

15 minutes lets the solver find quarter-hour handovers. It doubles the model, so expect double the waiting time.

Positions

Required vs optional, and what the ticks do

A required position must have someone on it for every minute of its hours. If that cannot be done you get INFEASIBLE.

An optional position is filled only from genuine slack, and never at the cost of any priority above it. It can never make a roster impossible. This is what Trg/IC is for: it fills as the strength rises and quietly disappears when you are short.

The hot seat is always ADC. It gets its own daily cap and its own fairness pass so nobody carries more than their share.

Bandbox means two seats worked by one person. Only pairs that can physically be banded are offered — ADC and Ground. Anything else is greyed out, because it is impossible rather than merely undesirable.

Note that the ATCO IC being held alongside a position is a different thing and is not bandboxing: the IC is a role layered on top of a seat, not two seats merged into one. That is why the IC can be alongside any position, including one that is itself bandboxed.

It is set per block, not per position, because it is only appropriate over the quiet periods. Each block of a position may name one other position it can be bandboxed with during that block — ADC and Ground bandboxed over the middle of the day, manned separately either side of it. Split a position into blocks with + block and set the dropdown on just the quiet one.

Bandboxing is permitted, never forced. The solver doubles up only when it needs to, and "Avoid bandboxing" in the priorities sets how reluctant it is.

Held alongside a position marks a role that sits on top of a seat rather than instead of one. ATCO IC is the supervisor: they can be IC while also working Talkdown, or IC while working ADC bandboxed with Ground — three at once. The would rather work box sets which seat they take first if they have to take one at all.

No relief needed exempts a position from the max stint and min break limits, so one person can sit on it all day. A run that mixes it with any other position is still capped, so nobody can chain ADC → ATCO IC → ADC into a five hour stretch. ATCO IC ships with this on.

Max changeovers caps how many times the seat changes hands over the day. Leave it blank for no limit. Useful on ATCO IC, where continuity matters more than sharing it about — set it to 1 and one person holds it all morning and another all afternoon. Set it too low and the roster goes infeasible, and the error will name this as the cause.

Min hold is how long someone must stay on that seat before handing over, which stops people churning through it. Careful here — setting 60 on GRD forces GRD onto its own handover phase and cascades into 90 minute stints across the whole day.

The four standard positions cannot be renamed or removed. Their hours, blocks, optional and hot seat settings are all still yours to change, and any position you add yourself is fully editable.

Staff

Untick the box by someone's name to stand them down. Blank times mean the full day — fill either to bring someone in late or release them early. Times are 24 hr, four digits, e.g. 1015. Untick a position under a name if they are not qualified on it yet.

Training / endorsement checks

How these work

A trainee sits on a position alongside a qualified person, so that position needs two bodies for the duration. The trainee does not need the position ticked under their name — being under instruction is the exception to that.

A supervisor needs both the trainer's course (TOC, ticked under their name) and the position itself. Neither on its own is enough.

Name a supervisor and only they will do it, for the whole thing. Leave it as Any and the solver picks whoever holds TOC, holds the position and is free.

A session is never handed over halfway through — the supervisor is fixed for the length of each unbroken block. If it cannot keep the same person for an hour it shortens the session instead. A separate block later in the day may have a different supervisor, which is allowed but discouraged.

Time is given in blocks of at least an hour, never scattered half hours.

Ideally between sets a preferred window, for a check that needs particular traffic off the flying programme. It is a want, not a limit: getting the training done at all comes first, and it will run outside the window rather than not run. Leave both boxes empty for no preference.

Essential means it happens or the day comes back INFEASIBLE. Unticked it is a want: the solver fits it if there is room. Rows higher in the list are fitted first when there is not room for all.

Where it sits in the Priorities list decides how much else gives way for it.

Hard limits (minutes)

What these do

Never broken. If they cannot all be met you get INFEASIBLE rather than a roster that quietly breaches one.

Leave any box empty for no limit at all. Values snap down to the time granularity above, so at 30 minutes an entry of 45 behaves as 30.

Min time on position is a floor, not a ceiling: anyone rostered works at least this much. Even with it blank nobody is left unused.

Max time on position without a break Min length of a break Max ADC per person per day Min time on position per person

Targets (minutes)

What these do

What good looks like, as opposed to what is allowed. The solver aims for these and reports how close it got. Missing a target never makes a roster impossible.

Ideal time on position Ideal break length

Priorities — what gives way first

How this works — read before changing

Every one of these is a preference, never a rule. Nothing here is ever guaranteed. The hard rules live under Hard limits and are the only things that are never broken.

The solver does not balance these against each other. It works down the list in order: it gets the top one as good as it can possibly be, locks that result in, then does its best on the next within whatever room is left, and so on down. Anything near the bottom may get no say at all, because the day is already decided by the time it is reached.

Press the ? on any row to see exactly what it does.

The order is locked by default, because changing it changes every roster the unit works to. Press Unlock and enter the password to move anything. It is a guard against an idle click rather than real security — anybody who opens the browser developer tools can get past it.

A higher number means higher priority. The numbers themselves mean nothing — only their order matters. Zero switches one off.

This matters most when short-handed, because there is not enough slack to have everything. With five in you cannot have both 1 hour stints and 1 hour breaks. Whichever sits higher is the one you keep:

• Stints on top → everyone gets 1 hour on position, but some breaks drop to 30 minutes.
• Breaks on top → everyone keeps a full hour off, but some people work a 2 hour double block.

Neither is wrong. It is a judgement about your people. The table under the roster shows what each priority actually achieved, in order, so you can see exactly what gave way.

Locked

Use the arrows to reorder. The top one is protected at everything else's expense; the bottom one gives way first. Untick to switch one off entirely.

Day watch roster

Results