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1. 12:05 PM - AFS fuel flow system display changes (Ralph E. Capen)
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Subject: | 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
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