Buffet is min speed but...
It is nice to know your low speed buffet for a particular weight and altitude, however I personally don't think that it is not too smart to be flying below drift down speed one eng inop.
I fly the 767 and we use as a ball park Ref30 + 100. (It is actual somewhere between +98 and +95, close enough). It would be easy enough to extract the figures for the 737 from the books.
If you know your min speed at sea level, you can simply add 1 knot for every 1000' above 20 000'. That equates the allowance for compressibility. This is important because aircraft stall relative to equivalent airspeed and not CAS.
Remember also that high speed buffet is in relation to Mach number but low speed buffet although it may be expressed as a Mach number actually happens at a EAS.
Good luck with the books!
Last edited by Colin Oskopi; 26th Jul 2015 at 06:00.