“The Purchaser can refuse to accept any materials delivered which are not in accordance with the original specifications or modified specifications as agreed between the Purchaser and the Vendor in writing. In such cases the Purchaser shall have the right to require the Vendor to replace, [COLOR=“Blue”]if necessary by air[/COLOR], such materials with materials to the proper and agreed specifications; all charges for such transaction being borne by the Vendor.”
I would assume that means overnight or two day shipping as opposed to ground shipping which takes longer.
To me that sounds like they’re saying “If the vendor screws up they have to fix it really fast”.
IMO, a less clunky way to say that would have been to replace the blue part with “within 48 hours” or “within two business days” or something along those lines.
In this context “if necessary” means “if the circumstances mean that it is required”.
And “by air” means “transporting the materials using an airplane”.
In other words, the Vendor must replace the materials, using air transport if required [for speed], if the materials are not to the agreed specifications.
By the way, in your first line you should have written “does” rather than “dose”.
It’s difficult to make such guarantees when dealing with international shipping, which is very common in trade outside the US. I believe Reza is from Iran.