bowling along at night in IMC conditions at 200ft for a planned 10 miles? Just nuts, as I know Crab and gulli agree
It needs to be looked at in overall context, had they been on a task to rescue some one from a boat in close proximity to Black Rock they would still have been operating at 200', and below, but they wouldn't have the radar return from the island covered by route data, as was the case.
There is a far simpler check that could and should have been done if this highly risky approach was going to be followed – just look at Google Earth
Absolutely nothing wrong with the belt and braces approach, but they already had the requisite information in the cockpit - the route guide, a pity the information wasn't presented in the style of an approach plate, with a profile view annotated with altitudes.
Checking Google Earth - The contract requirement was to be airborne 45 minutes after call out, they were 8 minutes late in meeting that requirement, so I doubt a lack of thoroughness in preparation was a factor. They originally were not going to Black Rock in any event, it was a diversion decision made in flight, I doubt Google would have been able to be accessed from the aircraft.