---------------------------------------------------------- Avionics-List Digest Archive --- Total Messages Posted Mon 01/31/11: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:05 PM - AFS fuel flow system display changes (Ralph E. Capen) ________________________________ Message 1 _____________________________________ Time: 12:05:34 PM PST US From: "Ralph E. Capen" Subject: Avionics-List: AFS fuel flow system display changes First, I'll preface by saying that I really like the equipment that these folks have for our planes and their customer service is top-notch - and I am an outsider not related to the company other than as a customer. Not bashing anyone here - just trying to get an understanding of who this change impacts and how it impacts them. My configuration started as a 3400EM - I have since upgraded to 3400sSP configuration (new processor and screen in addition to six-pack display) to have a set of backup instruments. The upgrade also included a Beta software release to fix a couple of last minute bugs in my system. Here's the scoop: I have 19 gallons per side for main tanks and 9 gallons per side for tip tanks for a total capacity of 56 gallons, with them all filled, the system reports 56 gallons available. Previously, the "Fuel Used" display only showed that fuel that has flowed through the flow-meter. If I only fill the mains, the system shows 38 gallons available and zero used. As I ran the engine for my flight, the "Fuel Used" display would increase from Zero by showing only fuel flowed through the flow meter. Now, the "Fuel Used" display shows the fuel that has flowed through the flow-meter plus the unfilled tanks. If I only fill the mains, the system shows 38 gallons available and 18 gallons used. As I ran the engine for my flight, the "Fuel Used" display would increase from 18 while adding the fuel that has subsequently flowed through the flow-meter. Somewhere during the flight, if I look at the "Fuel Used" display, I note that what is reported is getting close to what I just put in.....18 gallons early. Good safety margin - but not what I was expecting. I have queried the folks at AFS about this - they respond that the change was made in the interest of safety and to reduce confusion. Yes, I could simply not look at the "Fuel Used" display and only look at the "Fuel Available" display and cross check that with my fuel guages and time calculations for flight endurance planning purposes. I also asked for an optional flowed-only mode or to allow the user the choice of calculation methods (they still have the old code and it simply would be a system setting). I know that I am not the only one having trouble with this change - AFS indicated that they have received multiple indications of concern. Anyone else out there think this is an "odd change"? How are you (planning to) accomodating this? I am planning to try ignoring the "Fuel Used" display and see how that works....with a plan B of having multiple configurations (with and without tip-tanks) that I can upluad when Iplan to fuel the tiptanks. I don't expect them to change it back - but they may provide options if enough folks ask for it. Or, am I being overly picky about something that shouldn't matter - in the big picture? Your opinions please, Ralph Capen ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message avionics-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Avionics-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/avionics-list Browse Digests http://www.matronics.com/digest/avionics-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.