>..and then I suppose the next question must come, does the fuel selector
valve allow fuel through from both tank `halves when in reserve,
because if not, youd have to be changing tanks with ever diminishing
intervals to keep the big fan upfront humming after venturing into the
dreaded reserve?<
If you had both you would get significant amounts of air into the system as
soon as the lower side emptied which would then create a potential airlock
stopping the engine and preventing the use of reserve fuel.
This is one of the reasons for my parallel system. As soon as the main side
starts to lose fuel pressure the reserve side kicks in. This provides a well
defined reserve point and the system manages the system for you at a time of
high workload. With no action from the pilot the engine should only stop
once all the fuel has been consumed. You get a warning light at the reserve
changeover which, by my reckoning, gives a maximum of about 30-40 minutes
flying. Once you are on reserve you shoould be landing at the nearest
suitable airport.
Nigel Charles
|