Bladecrack,
prompted by your comments, I have re-read the thread regarding the Bond ec135 groundings in connection with the fuel probes. I may yet be missing something, but they clearly are concerned with quantity readings and the amber warnings. I know that the red warnings are separate, and indeed this fact plays an important role in my hypothesis of how events may have unfolded.
I would also refer you to earlier posts on this thread discussing "unuseable" fuel quantities in this type of aircraft. To summarise, there will always be fuel in the tank which cannot be accessed by the supply tanks and hence the engines. The quantity varies depending on aircraft attitude, and can be increased by incorrect transfer pump settings or pump/valve failures.