Low Fuel warning will not clear

[fr0gpil0t]

I'm flying a RV12iS with a Dynon HDX. Since I think upgrading to 16.4 I get a Low Fuel Warning message.

Digging into the Alert files I see a FUEL LEVEL LOW with a SHOW tag soon after boot up and then a few mins later FUEL LEVEL LOW with an ACK tag. I don't know if this is expected behaviour and it looks like it has been going on since I started to fly the plane in July.

In the past we never got an alert and the config file shows Fuel Level set to auto clear. I'm not 100% sure but I think this started after upgrading to 16.4 that the message appears about 80%. It seems like the s/w isn't picking up the ACK to clear the alert.

Is this normal behavior that the Fuel level is slow to read correctly and hence the Low alert ?

Anyone else seen an issue with 16.4 not clearing an alert ?

Do you know how to clear the alert manually?

Robert

 

[airguy]

What does your fuel indicator show? Is it possible you've got a bad fuel sender that is indicating zero? This could be a bad sender or a bad wire somewhere.

 

[fr0gpil0t]

Sorry I should have said that - fuel readings are perfect. I also assume why I see an ACK after a few mins as the system is acknowledging the fuel reading is good.

Robert

 

[fr0gpil0t]

Called Dynon support and they were zero help - sent me off checking stuff which is already clear in the logs and config files. I guess we will just fly with a low fuel warning !!!

 

[swatson999]

How about posting the sections of the logs and your config files here, rather than bagging on Dynon right out of the gate? Most of us have found them to be very helpful in the past, so being new here, maybe don't come out swinging?

Post what you have and let's look at it and see if we can figure out what's going on...

 

[fr0gpil0t]

I will post everything here. Yes my comments about Dynon were harsh but I was frustrated after my call. I spent hours researching this issue, gathering log files and config info. They didn't want to see any of that, just didn't want to accept it was an issue and sent me off to check something without taking time to understand the issue,.

 

[fr0gpil0t]

Following the update to 16.4 I get a fuel level low alert message that will not clear. But the fuel gauge measures accurately in flight.
I checked the Alerts file and you can see the message soon after boot but then you can also see the level message being showing as an "ACK", which I'm assuming is what clears it when the fuel level is measured correctly,

We had never seen the low fuel message prior to 16.4 so I checked back in older Alerts files and I see a similar behavior Alert generated and then cleared a few mins later. This is an RVI12iS and I must admit I'm surprised that it takes a couple of mins to get an accurate fuel reading. I've asked other RV12 owners to see if they see this pattern.

I've also included the sensor config so you can see the ranges are set correctly and the sensor is set to clear.

So two questions is it normal for the sensor to take a long time to get an accurate reading, and when it does why is the Alert not cleared ?

c37_p20={
valid=1
name=FUEL
id=FUEL LEVEL (RESISTIVE)
alarm_type=SELF-CLEAR
range={
max_display=20
min_display=0
range1_valid=1
range1_top=20
range1_bot=4
range1_name=R1
range1_color=GREEN
range2_valid=1
range2_top=4
range2_bot=2
range2_name=R2
range2_color=YELLOW
range3_valid=1
range3_top=2
range3_bot=0
range3_name=R3
range3_color=RED
range4_valid=0
range4_top=7
range4_bot=4
range4_name=R4
range4_color=YELLOW
range5_valid=0
range5_top=4
range5_bot=0
range5_name=R5
range5_color=RED
}
show_units=1

 

[swatson999]

Can you extract the actual data from the EMS Data Log for the times in question? That is, get fuel levels (L and R) between 14:35:32 and 14:44:44 (plus some on either side)?

 

[swatson999]

Alternatively, can you give us a link to a Savvy Analysis plot for one of these flights?

 

[fr0gpil0t]

Unfortunately it looks like the 16.4 set the update frequency of the log file back to once every 10 seconds and this was a 2 hour flight so I don't have the start of the flight, I store a lot of the flights on the savvy site so I am pretty sure I can match an earlier alert file to a EMS data log file. Standby.

 

[swatson999]

Pretty sure the software update didn't reset your logging frequency. It certainly didn't on mine. Not to mention that at .1 Hz, you can store WAY more than 2 hours of flight data.

 

[fr0gpil0t]

Is the low fuel alert triggered by the fuel computer going below a certain amount or by the fuel sensor showing low fuel ?

What does the ACK mean in the alert file - is this the system trying to clear the alert or some acknowledgment the warning has been displayed ?

Here are some examples on what a typical flights looks like.

There is only one fuel tank in the RV12iS and it's capacity is 20 gallons though the sensor only reads to 18g which probably explains some of the differences - but it it also looks like the flow rate needs adjusting.

Note between 16.2 and 16.4 the parameters recorded changed - fuel señor value vs fuel señor voltage not sure why ?

I am suspicious of 16.4 as since upgrading I've had this fuel level display issues, the flaps indicator disappeared and yes the frequency of the data gathering went back to 10 times a second, I cannot explain why I can only record 1:45 hrs of a flight at this frequency. The second graph is from 16.2 where I changed the rate to once every 5 seconds hence the longer flight time. I did not change it back to 10 times a second. I do notice there are old log files from previous releases stored on the Dynon - not sure if these are taking up space.

 

[airguy]

Unfortunately it looks like the 16.4 set the update frequency of the log file back to once every 10 seconds and this was a 2 hour flight so I don't have the start of the flight, I store a lot of the flights on the savvy site so I am pretty sure I can match an earlier alert file to a EMS data log file. Standby.

Note - all comments below are based on the experimental software versions - you indicate that you are flying an RV12, if it's the LSA version rather than EAB version, then your software may indeed be different.

There are apparently two different datalogs available to you according to Appendix F of the Dynon Installation manual (RTFM).

The "most recent flight" datalog records only the last 15 minutes of the flight at 16 points per second and is not adjustable. The normal "User Data Log" contains much more data and, at a recording frequency of 16 per second, will give you 2 hours of data. If it is set to once per ten seconds as you indicated, then it will hold 150 hours of data.

I have never seen an instance of a new software load causing a change in this logging frequency, and I've been beta-testing new software for Dynon for 6 years.

 

[fr0gpil0t]

I built the RV-12iS and it is registered as a E-LSA - EAB is used if you don't follow the plans and modify the kit. The Dynon uses the Experimental version vs their Certified s/w. Vans provides some config files which you install - the same config files are used for the planes they build and I'm sureEAB builders probably use them.

I agree there are the User Data logs where the frequency is configurable and the "Black Box" logs which are the last 15 mins. I am just stating that after installing the 16.4 upgrade - I saw the log frequency change, the flaps indicator fail and this weird low fuel issue start. You may not have seen something like this happen. The frustrating thing is I can't match the User Data log file to the Alert file I posted as I'm missing the first 15 mins.YMMV

 

[swatson999]

As Airguy pointed out...if the data rate is once per 10 seconds, over 150 hours of data can be stored, so something else is wrong with your system if you can't even hold 2 hours worth of data. I've never seen a software update change the recording data rate all on its own, especially since the logging rate is set by a *configuration* file, and not the software update.

As for the alert itself, it's the fuel level in the tank (as noted, RTFM). You built the plane, so you should be intimately familiar with all aspects of the avionics, including the configurations for all the widgets, sensors, etc. If not, go back and read the manual again, then go through the menus on-screen until you are.

Lastly, how about just providing a link to those Savvy pages. (People do this all the time...you can share the link to the flight itself, and we can only see that flight and display various data items, etc....it's safe to do this).

 

[swatson999]

Is the low fuel alert triggered by the fuel computer going below a certain amount or by the fuel sensor showing low fuel ?

What does the ACK mean in the alert file - is this the system trying to clear the alert or some acknowledgment the warning has been displayed ?

View attachment 5227

Here are some examples on what a typical flights looks like.

There is only one fuel tank in the RV12iS and it's capacity is 20 gallons though the sensor only reads to 18g which probably explains some of the differences - but it it also looks like the flow rate needs adjusting.

Note between 16.2 and 16.4 the parameters recorded changed - fuel señor value vs fuel señor voltage not sure why ?

I am suspicious of 16.4 as since upgrading I've had this fuel level display issues, the flaps indicator disappeared and yes the frequency of the data gathering went back to 10 times a second, I cannot explain why I can only record 1:45 hrs of a flight at this frequency. The second graph is from 16.2 where I changed the rate to once every 5 seconds hence the longer flight time. I did not change it back to 10 times a second. I do notice there are old log files from previous releases stored on the Dynon - not sure if these are taking up space.

View attachment 5230

View attachment 5228

What are the units on the X axis? Are these hh:mm, or mm:ss?

 

[fr0gpil0t]

As Airguy pointed out...if the data rate is once per 10 seconds, over 150 hours of data can be stored, so something else is wrong with your system if you can't even hold 2 hours worth of data. I've never seen a software update change the recording data rate all on its own, especially since the logging rate is set by a *configuration* file, and not the software update.

I've spent 30+ years either as a Support Engineer or managing Tech Support teams. I am providing all the information I have for context - I am pleased for you and Airguy that you have never seen an upgrade change a config. By now I think you have both made the point it is configurable. I saw this and a few other odd occurrences after the upgrade - if it's not valuable information then feel free to discard it but it happened ti me.

As for the alert itself, it's the fuel level in the tank (as noted, RTFM). You built the plane, so you should be intimately familiar with all aspects of the avionics, including the configurations for all the widgets, sensors, etc. If not, go back and read the manual again, then go through the menus on-screen until you are.

What's the point of just telling someone to RTFM. Yes I have read the manual it states the warning is driven by the fuel level sensor However Dynon support told me yesterday they think my problem is caused by the fuel computer triggering the warning.. Yes the fuel computer and the sensor can read different if you don't "true up" the fuel computer after a refill. I can't find any reference to the fuel computer triggering a low level fuel warnings. So I'm asking other users if they have seen something similar. After all isn't that what a user forum is for ? Anyone else seen a low amount of fuel in the computer trigger the fuel level warning.

Lastly, how about just providing a link to those Savvy pages. (People do this all the time...you can share the link to the flight itself, and we can only see that flight and display various data items, etc....it's safe to do this).

As with all Savvy plot hours and mins - will dig out the links.

I'm just trying to get some help here sorry if I seemed to have ruffled some feathers.

 

[swatson999]

No, it's okay, didn't mean to offend you, but what you're hearing is that, apparently, you're the first one to have a software update change a configuration such as this all on its own. It sounds like something *else* has happened to your system.

And the fuel level problem is very odd indeed...seeing the actual Savvy plot with the incident included will help, since we can then zoom in (and when zoomed in, Savvy should show hh:mm:ss).

If your configuration files got crapped out, then *perhaps* one of the parameters in there that is used to dampen out oscillations over time has gotten wildly off...the voltage level starts at 0 and immediately jumps to the correct value when the system comes up, but the value is averaged over a hugely long time?

 

[fr0gpil0t]

SavvyAviation

apps.savvyaviation.com

 

[swatson999]

I don't see anything wrong with the fuel level data. Looks like it comes right up at start-up.

Just to clarify...when you said in the first post:

I see a FUEL LEVEL LOW with a SHOW tag soon after boot up and then a few mins later FUEL LEVEL LOW with an ACK tag.

Do you actually get an alert on the SkyView screen at that time? You should have an audio alert along with the message and the flashing menu item per the manual. Do you not see or hear those?