Originally Posted by
Trip7
You haven't flown the plane in how many years and you still remember that? Impressive.
ASA 's procedure is to turn off both boost pump switches on during single. Leaving the operating engine boost pump switch on accomplishes the same thing since there is no low pressure sensed.
I've jumpsat on a Mesa 700 and I noticed they use the boost pump switch on operating engine technique .
Yes, we leave the pump on the operative engine side (on). It can't cause an imbalance unless the cross flow valve fails in the open position.
Originally Posted by
griff312
Correct me if I'm wrong, but... I believe that when you're running a single engine, with any boost pump on, both pumps operate and provide 200% of what the engine needs into the fuel feed manifold. Then then excess fuel is returned to the tank of the operating side engine, via a return line and motive flow ejectors. This can easily cause an imbalance, but which is usually corrected with auto crossflow, when operating. I believe our MEL procedure when operating with an MEL'd crossflow pump is to operate with both engines running, so that the excess fuel returns to both wing tanks, instead of just one.
Incorrect. The fuel pressure from the boost pumps is sufficient only to establish motive flow. You're guaranteed losing the engine if the engine driven pump fails, even with the boost pump on.