Yxcapt,. .. .I would agree with The Greaser to an extent, and then disagree.. .. .Vmca is a somewhat artificial speed that is a benchmark for aircraft performance. Changing the aircraft configuration does not change Vmca (it is fixed) but will change the airspeed at which you may lose directional control, subtle difference but makes you a test pilot every time you have an engine failure that is not in the configuration that the aircraft was tested in, or at any pressure altitude above ISA sea level. . .. .If the aircraft in question has a T/O flap setting, and that flap setting is more of a lift producing flap, then I would expect an increase in the speed that you would lose directional control as The Greaser described.. .. .A manufacturer may specify a greater flap setting than takeoff for the intentional demonstration of Vmca in flight to provide a greater margin above the stall (Vsse), thus providing a better buffer over a single engine stall/spin scenario. This may not necessarily be the most critical configuration.. .. .On initial thought landing flap IMHO may have no effect on Vmca, it would reduce climb performance, and increases the stall margin on both wings, and as you have eluded to (generally) produces a nose down pitching moment, but does it always change the relative airflow and therefore reduce P factor ?. .. .I would have to think about it a little further to come up with an answer for aircraft that have slipstreams that go over the flaps to see if full flap may actually reduce Vmca by the increase in drag caused by the slipstream on the flap, and therefore reducing the thrust couple of asymmetric flight.. .. .It is a complex dynamic situation, most of what we are talking about assumes steady flight (equilibrium), what happens if the aircraft is accelerating/decelerating, where is the center of pressure for the lift and drag in relation to the longitudinal, lateral, and normal axis, at what position is the drag vector of the wind milling engine acting through, the vector for the thrust of the live engine ?. .. .When talking about Vmca/Vsse there is no hard and fast rule that will always work it is dependant of the aircraft configuration and powerplant. The underlying principles are common, but always revert to the manufactures procedures for your type.. .. .Z. .. .The Greaser . .. .“This is the 'worst case' scenario for that plane and is the configuration on which the published Vmc is based.”. I would disagree with this, it would be as per regs, takeoff flap. . .. .Do not misinterpreted the published intentional Vmca configuration and procedure (Vsse - Single Safe Engine speed) as being the basis for the published Vmca speed. Vmca should be for sea level ISA, but I could wager your manual says to use this configuration at least 5000ft AGL for adequate spin recovery.. .. .Z