His Dudeness, why the fixation with seat pitch? To the best of my knowledge and reading of the paperwork, APD does not specifically target business jets. It is concerned only with the MTOW and number of seats available. Most "business jets" will be under 20t so it doesn't matter how many seats they've got, and I suspect just about all BBJs and the like have more than 19 seats if you count every available sitting space.
IMO, extending the APD net to include aircraft under 10t supposedly to plug an apparent exemption for corporate aircraft does nothing but penalise operators trying to make scheduled regional services work. As of 1 April, B1900, J32 & L410 operators have to hit their passengers with the charge.
