Section 45(4)(c) in The Air Corporations Act, 1953
(c)the cost or purchase of all serviceable general stores and all such other serviceable stores and spares parts (all of which are in this Schedule collectively referred to as stores and spare parts) belonging to the existing air company as are suitable for use in respect of the aircraft or power plants referred to in subclauses (a) and (b), reduced in each case by 20 per cent, of such case of purchase: