Ariz. Rev. Stat. § 42-14254 – Determination of value

A. On or before August 31 the department shall determine the full cash value of all flight property that is operated in this state in air commerce by each airline company. The full cash value is the value determined as of January 1 of the valuation year.
B. The department shall:
1. 1. Determine the valuation of flight property by fleet type.
2. 2. Determine the valuation of each fleet type by the original cost less depreciation.
3. 3. Compute depreciation using fifteen year straight line depreciation to salvage value. Salvage value is:
  1. (a) Ten per cent of original cost of aircraft that are out of production.
  2. (b) Twenty-five per cent of original cost of aircraft that are being manufactured as of January of the valuation year.
4. 4. Allow additional obsolescence if supported by market evidence.
C. Small flight property that is operated in this state in air commerce shall be valued at thirty per cent of its original cost less depreciation and additional allowed obsolescence.
D. The department shall determine the valuation that is apportioned to this state of each fleet type as the proportion of the total valuation determined on the basis of the total of the following percentages:
1. 1. Fifty per cent of the percentage that the total state ground time during the preceding calendar year is of the total system ground time during the preceding calendar year.
2. 2. Fifty per cent of the percentage that the total mileage scheduled within this state of the fleet type on flights operated in this state during the preceding calendar year is of the total mileage scheduled within and without this state of the fleet type during the preceding calendar year.