RE: What is a
A "waiver" in this context is a license to fly a turbine-powered model under the insurance coverage of the AMA in the US. The AMA safety code says that a modeler can not fly a turbine-powered model unless they have this "waiver" that is signed off by two other experienced turbine flyers. Its basically a mechanism to try and keep inexperienced or unskilled flyers like Mr. Islandhobbies from getting a turbine model and hurting someone or causing a lot of property damage because they can't handle the aircraft.
Bob