Active Minimum Control Speed (VCmin)

[MrBernoulli]

Active Minimum Control Speed (VCmin)

I have been trying to find a definition of VCmin and all I can come up with is that it stands for Active Minimum Control Speed.

Great, fine ............ but what does that mean? Can anybody help? Thankyou.

[MrBernoulli]

Oh well, VCmin can't be too important if there isn't some knowledgable aviator out there in PPRuNe-land who knows what Active Minimum Control Speed actaully is. What a shame.

I came across it in my aircraft flying manual and I haven't found anyone yet who knows what it means.

Sniff .......

[Mad (Flt) Scientist]

The only VC's I know of are the design cruising speed or the optimum cruise speed. FAR 25.335 and 23.335 talk about a minimum value for VC but never use the abbreviation VCmin that I can see.

"minimum control speed" is usally associated with the abbreviation "VMC" and it's sub-categories: Vmca, Vmcg, Vmcl. I've never seen "active" used in that context though.

Perhaps if you told us which aircraft it might right a bell for someone?

[MrBernoulli]

I came across VCmin in the technical manual for the B777. It is contained in the section on the autothrottle system and states:

“With the autothrottle armed, the autothrottle automatically activates if :
An autopilot or flight director is in VNAV XXX, FPA, ALT, V/S, or G/S and:
Speed less than VCMIN minus 8 knots for one second”

There is only this one instance of it, and no further explanation of the term VCmin. Having done some searches on the web, several sites blandly stated that it stood for Active Minimum Control Speed - but, again, no further explanation. These sites also mention: VCmax - Active Maximum Control Speed, but that doesn’t really help. The lack of information led me to ask the question on this forum.

Old Smokey, perhaps you could help?

[mutt]

This is frustrating me... Some sites found through google show the definition, but i cant find any Boeing reference to it.

Mutt.