http://en.wikipedia.org/wiki/Aircraft_maintenance_checks (http://en.wikipedia.org/wiki/Aircraft_maintenance_checks)
Interesting info about real life time durations and what's actually happening.
Very interesting :)
It looks like the 8 years between D-checks means we get it a bit easier than reality. Every 4-5 years would certainly have more of an impact on profits.
Maintenance model here is simplified, we have only time based checks and no flight/block hour / cycle based checks at all. Also the checks (type, name, duration) are the same for all types. In reality these all vary between models but data is of course prettymuch impossible to find for all models.
However if there are maintenance experts listening you could drop some comments on how to improve the realism on this area, without making it too complex.
Also of potential interest is that you can normally get a minor (say 7 day) extension to some checks if you need it to better fit the maintenance in. After 1 extension the a/c is then, however, grounded.
HJ