Originally Posted by
Maff
In the H135 the transfer pump and prime pump switches are now of different design, so by feel you know which are which. Once on, you leave the transfer pumps on even if the main tank runs dry, or a pump runs dry due to hover work with lower fuel, IMO a simple system and just two switches to put on along with other switches for other functions as part of the startup checklist.
Finally they fixed it!
Since when is this the case? A buddy of mine flying HEMS in an EC135 confirmed that the AFM demanded pump toggling when the active one is running dry due to fuselage attitude. That was a couple of years ago.
IIRC the EC135 has pump temp sensors that would activate a pump-xyz light suggesting to switch off the associated pump until it will be reemerged in fuel or something.