My reasoning for this is pretty simple really...
I imagine that after this rule were to go active, every aircraft on the second hand market would include a D check within the lease period.
The price of the lease would not reflect this increased cost and therefore, the wealthy players (those who can own aircraft) will get wealthier and the less wealthy players will have to cover the costs of D checks as well, thus making their bottom line even lower.
If the lease cost over the period reflected a reduction in cost equivalent to the cost of a D check, then perhaps that (albeit difficult to prove with nothing to compare to) would be reasonable and perhaps even encourage longer leases.
I see the renters getting screwed and the fat cats getting fatter ...
No offense intended.
Good to know, I'll take care you won't take one of my planes if you want to return them for D-checks.
The point is, that the buyer of the plane intends to earn cash of it, and since it is leased away it makes far less income than a plane you actually operate (for me usually 20-25% of the cash I'd make running it). But everytime when you lease out a plane, and get it back before a D-check (especially when the aircraft is a bit older already) the prior leasing income does not make up for all the costs. Maybe it would cover the D-check, but keep in mind, that those planes also costed a bunch of millions of $$$ to be bought.
In real life contracts are made prior to the lease itself, on which checks to be performed or not, and thereby also the actual price is negotiated. Since that is not possible in Airwaysim, there must be other ways. Currently I limit my planes to be bought or MAX. leasing at 0.5yrs, in order to make money on them and eventually pay such checks. This means a much higher leasing cost for the lessee.
Either I'd like to get the ability to charge 300% of their value for my planes, so that leasing cost would reflect a non-performance of a D-check. Or such minimu lease period should be introduced, in order to allow coercion on lessee to provide the checks.
Other option, as priorly suggested in another topic, would be to "write off" the checks, so that a lessee has to pay a certain %age of the checks not performed based on the time it operated the plane. So say the airline operated the aircraft for 4 yrs, and made a C-check prior to return, but left the D-check free, they would pay 50% of the D-check price, as they operated it for that long.
I'd like them all, but I think Ideas 1&2 are the easiest to program, so Option 3 is rather something for long winter days
Addement for Riger: There is also a simple principle about such things... "Don't like, don't take", someone who likes it, will take it. And If you should come up with the monopoly things about the high prices for player-sold aircraft on used market, keep in mind, that in most parts of the world there is no communism, but instead free (or social) market economy, thus a rare good will be raised in its price, and vastly available goods will have decreasing prices.