If the aircraft is for business, for example being leased out, the depreciation should not be provocative. Abuse would be not paying the corporate owner an arms length hourly rate for personal use. The business model might allow some modest marketing costs when re leasing. In some models, example aerobatic instruction and display, the business model may cover competition costs as part of marketing.
The USA has rules against hobby type business models where it is obvious the corporation is designed to help fund a hobby, and not with an objective to earn third party revenue.
I wrote up some stuff here and elsewhere. I imagine the USA (and every other developed country) must have a similar system to keep a lid on what the tax authority calls a “hobby business”. The actual depreciation is not the same thing as what you are allowed to write the asset down by (in the UK, called Capital Allowances) and the latter is usually substantial, say 25% a year, and this is obviously a useful thing to set off against tax (corporation tax or income tax, as applicable) if you can do it without getting undue harrassment which in the UK is virtually assured no matter how “arm’s length” you run it at.
Consequently my advice to anyone running a plane for personal + business is to keep it totally personal and charge the company for business mileage, as a % of total cost for the year pro-rated according to the % of airborne time, which is a very straightforward and recognised principle, and I am sure the US has a similar principle because business expenses are a universal thing.
So it is interesting just how US pilots manage to work this, because the only 100% taxman-safe scenario is where there is no personal use and (in the UK BIK scenario) no possibility of personal use. OR where you did an agreement with the taxman for x% being personal use.
The depreciation (actual loss of value) will be whatever it is when you come to sell it 
Probably, 25% a year is not too far off especially with a newly bought SR22.
Peter wrote:
The FTSE rocketed, especially after brexit
Only in pounds. If you compare the dollar value of the FTSE100 before and to now, the gains were much more modest (and it’s dollars you’ll need for buying an SR-22).
Even so, over the long run, conservative share investing returns about 7% which is far better than bank interest or government bonds. Even if you don’t do so well and only return 5% over the long run, it’s still a lot better than many other options.
