Originally Posted by
EDML
Question: From what I know the A/C category is determined using the Vref and not the specific speed flown in a circling approach. Correct?
The simple answer to that would be, yes. Just note that for the certification of the aircraft and when determining the aircraft category, the Vref on a straight-in approach and landing (not a circling approach (turning)) at Aircraft Max Landing Weight is used.
Since the circling approach requires banking (turning) during the maneuvering to land, the aircraft speed needs to be increased (above Vref) to increase the safety margin. The pilot will therefor need to use a speed with an increment during the circling approach, and depending on aircraft performance and operational procedures (Manufacturer or Operator), this speed may be higher than the MAX maneuvering speed depicted (for that aircraft performance category) on the approach chart. Accordingly, the operator may decide to perform the approach in a higher aircraft category (in the case of this accident Cat D) and using the minima's and performance criteria (such as circling protection area etc.) associated with that higher category.