I have a question,
On an HMU of any high bypass engine, the medium used to transmit any form of adjusting of the vanes and valves is done by pressurised fuel from the HMU.
But when fuel is pressurised at such an extend, it there a safety built in to protect the pressurised fuel lines from air/oxygen entering the fuel pressurised system. Because if air did get in, you would have not only an engine fire, but a wing fire I think.
What do you think??