Rotorfix
Only one pump failed (actually its drive failed) but, there being no check valves, it created a leak back to the sump so that the other pump could only muster about 5 psi or so into the gearbox, below the threshold for "land immediately" in the RFM at the time. In other words, there were 2 pumps but the failure of only one of them would bring the heli down. Good design!
HC