MX costs were raised, and their curve was flipped, since prior ages.
it is based off of both initial value [establishing minimum costs for each plane] and the lost fair value [establishing the raising costs with age]. In prior ages, it was just a flat percentage of fair value of aircraft owned [meaning it decreased as planes got older].
Color me confused (and I know zilch about aircraft maintenance)...
* I thought in the 2000 and 1950 round, aircraft maintenance costs was a flat percentage of initial value? (Not a declining scale.)
* Because I believe it was Stephen who said that real-life aircraft maintenance costs decrease over time (although it does have to increase again at some point, right?)
the flat percentage was off of fair value, not initial value... unfortunately. Either it was misquoted or misremembered. it's somewhat unrealistic.
The only way to make maintenance costs decrease over time is to have operational efficiencies and economies of scale [fleet uniformity and scale]. Hiring one MX team to maintain one plane type when there's many types in use and few of each is expensive and inefficient. for fewer models, especially related families, one could hire fewer MX teams while providing the same level of maintenance as there'd be less "down time" for each team.
A plane is, otherwise, similar to automobiles in one respect. the older it is, the more likely it needs more expensive maintenance. that newly delivered Boeing is much less likely to need some significant part replaced then a 20 year old counterpart, just as a new car is much less likely to need a new transmission then a 10 year old counterpart. Not perfectly true in all cases, however it is generally true and reasonable.
We're hoping sooner or later to get an impact on MX costs based on fleet uniformity, however at the moment i'm unsure how to properly implement it as we haven't kept accurate enough records of what airplanes are related to each other and what aren't. [for instance, i know a Fokker 70 is highly related to a Fokker 100, however the database has no way of knowing that. either it'd less correctly penalize you for having 2 types it thinks are unrelated, or overzealously spot you a "related" bonus and likely give you a "related" bonus for having a 737-200 and a 777-200.]
The other way that scale simply reduces maintenance costs is the more planes you have, the more likely there's a spare to fill in while one plane is down for maintenance. if you only have one plane, that time in shop is loss of revenue, whereas if you have two dozen planes of the same or similar types, one can probably fill in for t'other for that period. At present, maintenance time is either "buried in turn time" or "ignored". from the looks of some turn-times, it's most likely ignored. We're also planning on rectifying that at some point in the future.