(1)Notwith-standing anything to the contrary contained in sections 28 to 43-A, in the case of an assessee, being a non-resident, engaged in the business of operation of aircraft, a sum equal to five per cent. of the aggregate of the amounts specified in sub-section (2) shall be deemed to be the profits and gains of such business chargeable to tax under the head "Profits and gains of business or profession".
