An aircraft needs two kinds of work: scheduled checks by flight hours and repairs of defects that appear after flights. Both cost money and downtime, and an overdue check grounds the aircraft.
Scheduled checks
Checks count flight hours: an aircraft sitting on the ground gets no closer to them. A heavier check includes the lighter one’s work, so the lighter one starts its interval over afterwards. A used aircraft keeps counting from the hours it came to you with.
The mass-market families (A320, 737, 777, A350 and others) have their own programme of three checks, L, M and H, due on hours or landings, whichever comes first; the aircraft card shows when each falls due.
For these families the H check is also due by the calendar, at least once every six months, even if the aircraft stands idle. The date is in the Resource to maintenance block, and missed months add up to just one H.
Ordering and cost
“Schedule” puts the job in the aircraft’s queue: a free aircraft at the maintenance airport goes in at once, a busy one after its flight. If the aircraft flies to that airport on its route, the queue waits for it; otherwise it is ferried empty at the airline’s expense, and the window shows the ferry price up front. Money is charged when work starts, so cancelling before that costs nothing.
An L, M or H check can be ordered once it has used 90% of any of its limits. An H check that came due by the calendar cannot be completed early.
The aircraft’s maintenance fund pays: it builds up from every flight as the “Maintenance reserve” line and is spent on that aircraft only. Whatever it lacks comes from the airline account, and when the aircraft leaves the fleet the rest of the fund returns to the account.
If a job won’t start, the aircraft card’s Dispatcher tab says why.
What each job restores
Any scheduled check also clears the small defects that have piled up. Hard-landing damage is not fixed by a check, only by a targeted repair.
Overdue checks
While the interval has life left, it is your call: do the check early or fly it out. An overdue aircraft cannot be booked, put on a charter, taken on the flight of the day or given to an AI crew, and the tracker will not start a new flight on it. A flight already under way flies on.
A base mechanic books an overdue check nobody ordered on his own, paid from the maintenance fund and the airline account, at most one job per hour. With planning ahead allowed on the Hubs page he also takes checks marked “due soon”. If there isn’t enough money, the job is not booked and a letter says so.
Wear
The closer a check, the more the aircraft costs to run. The “Life to maintenance” block on the aircraft card shows the hours left to each one.
Defects
- Wear defects: small and near enough unavoidable, they trickle in after flights and with time.
- After a hard landing (roughly 600–1000 fpm), one or two more serious ones.
- After a heavy landing (beyond 1000 fpm), a critical defect, and the aircraft stays on the ground until it is repaired.
A repair is paid for and keeps the aircraft on the ground while it runs; the price depends on the defect and the aircraft’s value. “Fix all” opens one repair for the whole log: faster than one by one, but each defect is still paid in full.
With the new damage model (switched on after the scheduled-maintenance programme) one event gives one repair package instead of a scatter of defects. Level 1, a minor fault after a flight: fix within 7 days, after that the aircraft won't be dispatched; costs 2 hours of the type's maintenance reserve, 1 h on the ground. Level 2, a hard landing: repair before the next flight, 12 reserve hours, 4 h. Level 3, severe damage: grounded until repaired, 48 reserve hours, 12 h. The aircraft's maintenance fund pays first, hub discounts apply. Scheduled checks don't close a package and the base mechanic doesn't fix it for free. If «maintenance checks without you» is on in the bases page, the company orders the repair itself: levels 2 and 3 at once, level 1 in a free slot; otherwise the package waits in the aircraft's log until the owner orders the repair.
Personal aircraft
A personal aircraft from “My hangar” has no check tiers: “Service the aircraft” takes an hour and brings the airframe, structure, engines and cabin back to 100%, clearing wear defects. The price is fixed; the aircraft’s maintenance fund pays first and the rest comes from your personal account. Hard-landing damage still needs a targeted repair.