In an aircraft 1031 exchange, an aircraft or engine held for productive use in a business or for investment sold and acquired for an aircraft or engine of equal or greater value effectively defers the capital gain and recaptured depreciation taxes triggered by the sale. The old aircraft can be sold first followed by the purchase of the replacement aircraft, or as is typically is the case in a reverse exchange, the replacement aircraft may be acquired first followed by the selling of the old or relinquished aircraft within 180 calendar days. General Asset Class 00.21 of Revenue Procedure 87-56 classifies “airplanes (airframes and engines), except those used in commercial or contract carrying of passengers or freight, and all helicopters (airframes and engines)” as like-kind.