Depreciation is allowable if an asset (1) is used for business or held for the production of income; (2) has a determinable useful life exceeding one year; and (3) wears out, decays, or becomes obsolete, or loses value from natural causes.
Would you say your use of the aircraft qualifies for use in a business or the production of income? If so, then deprecation begins when it is placed in service.
If you could depreciate the aircraft, then your tax guy appears correct. Internal Revenue Code Sec. 1016(a)(2) requires you to reduce the basis in your asset by the greater of the deprecation allowed or allowable (an operative term), meaning that if you were allowed to depreciate an asset but did not, you would still have to reduce the basis by the amount of deprecation that you could have taken, if it is greater than what you actually took.
The only good thing here is that if you did not claim depreciation, the basis reduction is used to determine your gain or loss, but you don't have depreciation recapture.
Depreciation recapture is a concept that requires you to pick up as ordinary income (not capital gain income) that portion of gain that represents deprecation claimed on that asset. For example, if you purchased an appreciating asset for $100,000, depreciated $30,000 of it, and sold it for $110,000, you would have total gain of $40,000, but $30,000 of that would be ordinary income (depreciation recapture) and $10,000 would be capital gain.
I hope that helps.
