Transmission Design
I have been looking for my copy of the HARP Report (Helicopter Airworthiness Review Panel) produced by the UK CAA in the 80s following too many helicopter accidents that had technical related issues - can't find it so this is from memory.
The report essentially said that many aspects of helicopter design equated to the Dakota era of fixed wing design and that transmissions that included high speed sections within the main casing like the S61 - which at that time dominated the offshore world - were definately out of order. The report implored manufacturers to find a better way with less criticality. I believe the 30 minute run-dry time was meant to indicate that the design indeed had less critical failure modes. I don't believe it was ever envisaged that we, the flight crew, would interpret that to mean that it gave us more 'get-you-home' time. It is easy to see though that when you are up against it the pressure is on to make it those last few miles to the beach.
I recommend the HARP report (maybe someone can post a link if it exists on-line) because I think that as a retrospective it would make fascinating reading in the context of recent developments.
G.