Preflight smart fuel warning on the dispatch board.
Dispatch now estimates fuel at return before every flight: usable fuel on board (current level minus unusable) minus the aircraft's estimated burn rate times the planned duration. If less than an hour of burn would remain at return, the dispatch shows a yellow 'refuel before engine start' banner; if the planned flight would run the tanks past usable, it shows a red insufficient-fuel banner with a PIC acknowledgment button. Advisory only — the pilot in command always retains go/no-go authority — and the check stays silently off until an aircraft has a burn rate and current fuel level configured.