Fuel Quantity Selector Question

Vibora,

I got say I like the C-101 very much, and I am happy you are working on the PFM for it.

I have a question for you. In the manual checklist (and on the quick start guide) on the Before Start and Taxi sections it says:

Fuel Quantity Selector ____ FUS

I don’t understand the reason for that, especially because there is no step later to select “not” FUS. This obviously does not affect the operation of the aircraft but I am curious on how the system works. Maybe somebody can shine some light on the reason for selecting the FUS indication only. I think the real aircraft manual available in the internet doesn’t have that, but my Spanish is not very good, and I remember reading that this manual is not the latest one.

Thanks and keep up the good work.

It's not easy to answer your question why FUS shall be set in the C-101EB checklist. I've asked SME to try to get an answer. What I can tell you is that one reason could be to be able to detect soon enough a fuselage fuel leak. When FUS is not pressed, you get both fuselage plus center wing tanks indication, and you wouldn't notice that you're losing fuel until indication goes bellow about 3000 pounds, and in that case you could have lost about half of your fuselage tank fuel. Being the fuselage tank the critical one, since the engine feeds from that tank, you could end up in a difficult situation, which you could avoid with a quick fuel leak identification in fuselage tank if you have FUS selected.

It may very well be because what you said. I thought maybe there was some automation that the FUS would disable (for the takeoff for example). On the other hand, the FUS light is very good at alerting the pilot when the other tanks are empty (or not transferring), and you lose that keeping it on. Thanks for the response, appreciated it.