As FlyingStone said the Cat speed is basd on Vs0 X 1.3
The Seneca has a stall speed in the landing config (Vs0) of around 62 knots give or take. I don't have a manual handy.
Lets call it 65 knots to be on the safe side. 65 X 1.3 = 84.5 call it 85 knots.
Therefore it is a Cat A aircraft, i.e. it can be flown at speeds that apply to Cat A aircraft and providing you fly it at those speeds the Cat A approach minima apply.
If you elect to fly at higher speeds than the Cat A speeds then you must apply the higher minima for the appropriate category speeds. One aircraft I fly is Cat A, it is much happier about 5 to 10 knots above the max Cat A approach speed so I fly Cat B minima.
Last edited by 27/09; 17th Oct 2014 at 09:00.