Safe Single Engine Speed: What is SAFE?
A group of us are developing and ratifying SOPs for a heavy twin helo. In discussing non-Cat A departure and arrival procedures, there is a difference of opinion as to what speeds the PM should call during transition. Historically we have called Safe Single Engine Speed (SSES), but on a new machine we now have to option of deriving a SSES based on max continuous power, 2 min or 30 sec contingency (don't know exactly what the legacy numbers were based upon as the technical data is weak to nonexistent).
So the question is: What constitutes SAFE?: Sustained flight?; max climb?; immediate obstacle clearance?; accel to Vy?.....
Some communities (and the OEM) use 'Stay-Up Speed' which is based on max continuous power OEI. This will only allow sustained level flight. Equally so, flight at 30s or 2 min 'Safe Single' only assures level flight (for the next 30s or 2 min). In either case, should a climb be required, one needs to accelerate to a speed closer to Vy.
Then, is there any value in calling the lower 30s SSES? It would assist the PFs SA, but the likely result is contining to accel to Vy anyways. Does the call provided any value over waiting another second or to until, say, Vtoss or Stay-Up?
I'd be curious to hear what other communities do, and specifically the reasons why.