Wear, hours and checks

Aircraft in The Airline Tycoon do not age in years. They age in block hours and in cycles — one cycle being one takeoff and one landing — because that is how aircraft actually age, and because it makes the way you fly an aeroplane matter as much as how long you have owned it.

The practical consequence: two identical aircraft bought on the same day can be in completely different condition a month later, and the one that flew short hops all day is the tired one.

Hours and cycles

A long flight accumulates hours and one cycle. A short flight accumulates few hours and one cycle. Since the cycle is the punishing part for structure — pressurisation, undercarriage, brakes — a regional aircraft doing eight sectors a day wears out faster than a widebody doing one, even though the widebody covers far more distance.

The game weights the two according to what the aircraft is. Turboprops and regional jets are built for cycles and suffer less from them than a long-haul aircraft would; a widebody flown on short sectors is being used against its design and the wear reflects that.

Wear

Wear is the running condition of an individual aircraft, and it rises with every flight. High wear does not make an aircraft unprofitable in a subtle way — it makes it unusable: past a threshold the aircraft is grounded until it has been checked, and no departure will be accepted.

You will see this coming. Wear is shown per aircraft in the fleet list, and planning a check before the aircraft stops flying is considerably cheaper than discovering the ceiling on a busy day.

Checks

There are two.

An A-check resets wear. It is the routine one: the aircraft goes out of service for a while and comes back fit to fly. Budget for these; they are part of the cost of operating, not an emergency.

What it costs follows three things, and none of them is what you paid for the aircraft:

The size of the cabin. A 400-seat widebody is a bigger job than a 70-seat turboprop, and it is billed like one.
How worn it is. A check at 30% wear costs half what a check at 60% costs. There is nothing to do on an aircraft that has just flown out of the hangar, and it is free.
How long you left it. Above 70% wear the price rises by 2% for every further point. Deferring a check costs more, not less — which, together with the reputation you lose flying above 70%, is why running an aircraft to the ground is a decision and not a saving.

Older airframes carry a surcharge on top of all three. The premise of the whole fleet page is that cheap old aircraft are cheap to buy and expensive to run, and the workshop bill is where you feel it: a Tu-154M costs more per departure in maintenance than a 737-800 does, despite costing a sixth as much to buy.

A D-check is the heavy one. It resets wear and takes hours off the airframe's effective age, which is the only way to make an old aircraft young again. It costs accordingly and it takes the aircraft out of service for considerably longer. Whether it beats selling the aircraft and buying a newer one is a genuine calculation, and it depends on what the aircraft is worth on the used market at the time.

Checks take real workshop time, and in a scheduled week that time is departures. You can let the auto A-check rule catch a worn aircraft whenever the threshold you set is crossed — same price, but whatever was in the timetable right then is missed — or you can plan the check into the week grid yourself, in a night gap or a quiet weekend, and lose nothing. The rule is the safety net; the planned service block is the craft. A hangar shortens every workshop stay.

The maintenance factor

Here is the part that catches people out. Your maintenance costs do not depend only on the aircraft being maintained — they depend on how varied your fleet is.

Every additional aircraft family you operate raises the maintenance cost of everything you own. Every additional model within a family raises it too, by less. The reason is the same one that drives real airlines to standardise: separate spare parts, separate tooling, separate engineer training, separate manuals.

So the airline that buys whatever looks good this week pays a premium on its entire fleet, forever. The airline that picks a family and stays inside it pays the least. The factor is capped — variety does not become ruinous — but it is large enough that a mixed fleet needs to be earning something for the trouble.

This is why the fleet page shows your families and models as a number rather than burying it. It is a cost you can only see by looking at the whole fleet at once.

Preferred suppliers

You can name a preferred supplier and get a discount on both parts and maintenance in exchange for committing to them for a period. It is a straightforward trade: a real saving now against a loss of flexibility later, and the flexibility matters most exactly when something goes wrong.

Practical notes

Plan A-checks; do not react to them. The cheapest moment is earlier than it feels, and the price curve above 70% wear is steeper than the reputation loss suggests.
A short-haul aircraft's real cost is in cycles, so a schedule of very short sectors is more expensive than the fuel bill suggests.
Before buying an aircraft from a new family, work out what it does to the maintenance factor on everything you already own.
A D-check on a much-loved old aircraft is sometimes sentiment. Check the used market first.