VOR pressure sensing?

[HPSOV]

While recently resting my head on the coaming of a 767 I noticed all the wires coming out the back of the VOR and MCP. Among them was a clear plastic tube going into the back of the VOR, it was marked L VOR PRESSURE SENSING. My question is what on earth does it do? Last time I checked the VOR wasn't a pressure instrument... am I missing something??

[dv8]

Might be total rubbish but
alt sensing to correct for DME slant range error?

[QAVION]

Can't say I've noticed them before, HP, even though I've changed quite few MCP's and VOR control panels, but now that I think about it, I'll hazard a guess and say that they are equipment cooling flow sensing lines. If you look over your shoulder to the 1st Obs panel, you'll see an equipment cooling test panel which consists of a thin plastic pushbutton below a row of clear, vertical tubes. You push the button and watch little white balls rise up into view inside these tubes indicating that the equipment cooling air flow is OK. No doubt, one or two of these "test tubes" will be marked VOR or MCP?

Cheers.
Ia... er... Q.

[HPSOV]

Thanks Qav! I knew there had to be some simple explanation, but its a good one I can get the skippers with now!
:-)