HC,
Correct me if I am wrong (it's been a long time), but the inlet for the ELS was below the intake for the main pump, so even if the main pump poured all the oil it could pump out, the ELS could still operate.
OK a hole in the bottom of the sump would mean ditching.
I think requiring a 30 minute dry run capability is not stimulating progress of offshore helicopter design. 30 mins is only of use to onshore work. As oil fields are found further offshore, we are looking at longer ranges and therefore higher exposure during "land as soon as possible"/"nursing it home" scenarios. We are a long way from a dry gearbox which would be the ideal solution - no oil, nothing to leak, no pumps to fail. In the mean time, the regulators should be requiring the manufacturers to develope a means of making sure we can make a safe landing/get home in the event of failure of an oil system component. I.E. relate the regulation to the range of the aircraft. Something along the lines of providing a supply and/or emergency supply of oil that cannot leak by gravity and cannot be pumped out of the gearbox by the pumps. Of course there is a problem of cooling, but since heat is a measure of inefficiency, there will be incentive to design more efficient transmission systems.