My question should have been:
A pilot for a large aeromedical vendor in the USA, said that his employer was going to submit an STC to the FAA that if approved (it made sound more like "when approved")would grant them the capability to operate at a higher gross weight than the one imposed by Pt.27 certification.
This would be for operations under Pt.135 in the USA.
He said it was a done deal.
Would this be possible?