Wizofoz,
What makes you think I was referring to you?!
If your main arguement is `comply with one`s own company SOP`s` then we are in complete agreement! HOWEVER that was not the reason for the original thread. On the three Boeing types I have flown (B707, B737, B747) the maximum Vref increment was +20kts. I also flew with one operator who used the minimum reference ground speed concept on these types. The problem arises when the expected change in headwind component decreases by more than that amount. To berate Chris about his use of scientific terms and to quibble about frames of reference misses to whole point of the arguement! An Airbus, using mini-GS arrives over the threshhold at a SUITABLE GROUND SPEED and a SAFE IAS!
QED