Police helicopter crashes onto Glasgow pub

[Sven Sixtoo]

Fuel faults

I throw this in for one of the EC135 operators / engineers to comment, as I can't readily lay my hands on a LP fuel system schematic.

In the Sea King, we had a vaguely similar fuel system, in that all the working bits were in the collector tank (I suspect equivalent to the supply tank). Now one of the things that could go wrong was that if the pipework between the back and the front (where the collector tank was) became disconnected inside the tank, then the collector tank could be at the same level as the main tanks. In a Sea King, which held 6000 lbs of fuel (american aircraft) and had a minimum when I started of 85 lbs / side, the result of a pipe disconnect downstream of the transfer pumps and a leaky collector tank inlet valve would be absolutely nil, just as long as you didn't manoeuvre the aircraft hard at a low fuel state. There was, when I became the MTP for the RAF SAR fleet in the mid-90s, no check at all for these two pre-existing failures, and no cockpit indication direct or indirect that they were present.

Where I am headed with this boring old duffer's discourse on an unrelated and otherwise quite dissimilar type is:

What mechanical failures could cause the EC135 supply tank to be near empty, when the lack of failure indications could give the pilot the impression that it should be full? Are any of those failures of a type that could lie dormant for long periods? Could such mechanical failures (splits in feed pipes within the tank system, for example) be hidden from a post-crash inspection by the gross disruption of the lower fuselage?

I lack the knowledge to offer an opinion in respect of the EC135, but I have seen several dormant faults of this type on the Sea King once we went looking for them.

Sven