Originally Posted by
BeechcraftPilot
I'd like to talk about light twins in this situation. We should consider speeds like Vmca during all phases, including approach and landing. Don't you guys think that can be a dangerous approach with less speed than published?
Vmca is not a concern during the final phase of approach and landing, once one has committed to land. The Vmca published for a light twin (FAR 23 twin) is based on one engine at takeoff power and the other one inoperative. During the final phase of approach and landing in a typical light twin, each engine is only producing about 25 to 30% of rated power. Should one fail, the other only needs to be increased to 50 to 60% of rated power.
In real world operations, if you are 5 mile back on the ILS, you are almost always above Vmca, so it's not a concern. At one mile from the threshold, when you start slowing down to Vref, you are generally committed to landing, hence there is no possibility that you would need to apply 100% power to the operative engine in the event of an engine failure.
My comments are based on thousands of hours in a 12,500 pound twin turboprop, but I think the same concepts would apply to most light twin engine aircraft.