Musket 33,
Surely the only requirement for 155 to operate Cat A is Shell, no? I thought Bell 212 was operated Cat A as well, just it has a shorter reject distance and having skids, can be operated off grass in rainy season Cat A (unlike 155, which rolls over when the wheels dig in to the mud.
Does the 155 operate Cat A from all the flow stations and offshore as well? If it's operating Cat A offshore how many passengers can it lift using helipad profile?
They do have performance charts to operate Cat B for 155. Your Operations Manual must specify what the DP is for Cat B or Class 2 operations (normally either Vtoss or Vy after which the national legislation will normally specify you must have Cat A performance. Normally the Cat A will be limited by something like the single engined performance en-route (normally something like...... must be able to maintain level flight on one engine at Vy at SE max continuous power). So all you have to do is go to the single engine performance graphs and work it out. If you fly 155 and 212, just go to the graphs and compare for yourself.