For many, many years (20-30+), I have been totally familiar with the term "PILOTAGE Exemption Certificate".
It is an English-language phrase but, since English has become the international language of the shipping industry worldwide, it or its abbreviations may have been corrupted, altered or misusede in various parts of the world but, I can assure you, that PILOTAGE is what the P in PEC originally stood for.
Pilotage exemption certificates are, I think, a lot easier to get nowadays than they were in the time that I was writing magazine articles about them.
As I remember it, almost the only ships on the Thames that had pilotage exemptions were the