The difference between an off the shelf S-92 and a VH-92 will be significant. Starting with a commercially certified VVIP S-92 and then adding basic the requirements for US Presidential Transport (i.e. EMP hardening, defensive avionics, ballistic protection, ……) will add significantly to the basic and all up weights of the aircraft. At some point, the basic dynamic components will have to be upgraded to meet these increases in weight.
....but the rules say no upgrade development is acceptable and the offer has to be already certificated so mods to the S-92 should be ruled out.
