I agree with the previous posting as the fleets of both Iran Air and Mahan Air consist of largely 20+ year old airframes. So how does Iran plan to get around this then? It's more than an operational headache to both of these Carriers and yet others with 20+ year old aircraft in their fleets appear to be operating normally. Even if they have begun to cannibalize in order to source spare parts such airframes aren't exactly falling from the sky on a daily basis.