Bad requirement -
So what is the Pilot instruction to be in the AW189? loss of oil? No problem, you can fly for 50 minutes, we promise.
How about some way of knowing what your real status in that situation is? Aux lube system, you know the pressure, you have real faith. One demonstration, without flight conditions, attitude, what is your standard deviation in results? This release, and the basic requirement itself, only perpetuates a false comfort to go farther than you should. Landing immediately in cold water may be a bad day, but beats the alternative. What if you really only have 25 minutes that day, because the leak initially caused a loss of cooling that you did not notice?