Info and Warning Rings on Remaining Fuel

[Randall Karstetter]

I love the gliding ring that calculates for terrain and winds aloft. I used to cringe when I told my friends using Foreflight that my EFB didn’t have that. I even like it has two rings, a green one for a conservative distance and a red one for Never Exceed (and don’t trust it to be totally accurate). But something I would like to see (and I don’t know if Foreflight has this) is a calculation of remaining fuel, winds aloft, and a ring (maybe orange or another color) surrounding the plane that shows all areas that a landing could be made with 45 minutes reserve. And an outer ring (maybe dark red) that shows the absolute limit of remaining fuel. This would be handy if approaching an airport and suddenly hearing the airport was closed due to a wheels up landing and you have to quickly find (and calculate fuel reserves for) another runway. Also, I once was approaching my destination airport and they broadcast on CTAF that they ran out of fuel and issued a NOTAM as well. It would really be cool if iFly could receive that NOTAM and quickly recommend a diversion airport within the fuel reserves. But at least having a fuel ring visible would be a big help. Another big help would be a display on the ring of the amount of flight time of both the orange ring and the red ring. In an emergency ATC wants to know the fuel time on board and the number of souls. Just looking at the red ring would get that number and reduce the workload on the pilot at a critical, high-stress time. I know this might be a programming challenge, but it could be an incredibly useful and potentially life-saving feature just like the glide rings.

 

[Cobra]

I love the gliding ring that calculates for terrain and winds aloft. I used to cringe when I told my friends using Foreflight that my EFB didn’t have that. I even like it has two rings, a green one for a conservative distance and a red one for Never Exceed (and don’t trust it to be totally accurate). But something I would like to see (and I don’t know if Foreflight has this) is a calculation of remaining fuel, winds aloft, and a ring (maybe orange or another color) surrounding the plane that shows all areas that a landing could be made with 45 minutes reserve. And an outer ring (maybe dark red) that shows the absolute limit of remaining fuel. This would be handy if approaching an airport and suddenly hearing the airport was closed due to a wheels up landing and you have to quickly find (and calculate fuel reserves for) another runway. Also, I once was approaching my destination airport and they broadcast on CTAF that they ran out of fuel and issued a NOTAM as well. It would really be cool if iFly could receive that NOTAM and quickly recommend a diversion airport within the fuel reserves. But at least having a fuel ring visible would be a big help. Another big help would be a display on the ring of the amount of flight time of both the orange ring and the red ring. In an emergency ATC wants to know the fuel time on board and the number of souls. Just looking at the red ring would get that number and reduce the workload on the pilot at a critical, high-stress time. I know this might be a programming challenge, but it could be an incredibly useful and potentially life-saving feature just like the glide rings.

Welcome to the iFly forums! Re: your request:

How would iFly know how much fuel you have onboard?

How would iFly know how fast you are burning your fuel?

Based on your answers, how confident would you be in iFly's predictions? How "foolproof" do you think they would be?

 

[Randall Karstetter]

Welcome to the iFly forums! Re: your request:

How would iFly know how much fuel you have onboard?

How would iFly know how fast you are burning your fuel?

Based on your answers, how confident would you be in iFly's predictions? How "foolproof" do you think they would be?

Cobra, Good questions that I've been thinking about. I'm a programmer so I've got some ideas. It's difficult for iFly (or any EFB) to calculate fuel burn and remaining fuel without input from fuel flow sensors or gas tank sensors. However I think a good approximation could be calculated from pilot testing and pilot entered data. For instance, EVERY time I fly I dip the tanks and measure gas amounts before engine start. Then at the conclusion of the flight I dip the tanks again and measure fuel used. I then use my TACH time to know average GPH. I make note of my cruising RPM, whether I leaned or not and what I leaned to, the altitude I flew at and the distance I flew. I'm not concerned about headwinds or tailwinds because it's the engine time and GPH that are the most critical and those aren't affected by winds. With this basic information I can pretty closely predict my fuel usage on another flight of similar variables (altitude, cruise RPM, amount of lean) with the time aloft increased or decreased by the winds to calculate how much fuel I'll need. So preflight I could input into iFly my predicted average GPH at the planned cruise altitude and expected RPM (based on previous similar flights), amount of fuel onboard, and cruise planned lean (if any). After that the only variable that could vary would be the actual headwind component of the winds aloft at the cruise altitude. That's something iFly could obtain and constantly recalculate the ETA and fuel needed. iFly could have a button to bring up current fuel usage parameters the pilot could change such as RPM's, planned cruising altitude, amount of lean and/or fuel flow if plane is so equipped. The pilot could check if everything is still current or edit it if things have changed. By this interaction and information exchange between the pilot and iFly, the workload of constant calculating fuel usage and fuel reserves could be done by iFly and displayed on the moving map and digitally as well. It may not be perfect, as it does rely on accurate input from the pilot, but for those pilots who want to take the time to enter and update accurate information this could be a welcome assistance to flying. I know I would sure love to have something like this to help me monitor fuel usage and fuel range alternatives. Especially the real time winds aloft calculations on fuel endurance would be worth the price of gold. And what would really be cool is if I input the fuel remaining at the end of each flight and iFly then accumulates the information captured on each flight and can become better predictive of fuel usage and range for future flights. But this would likely only be possible when AI is incorporated into iFly. Which I'm hoping someday it will.

 

[Randall Karstetter]

Something else to consider. Fuel starvation is a significant factor in many GA accidents. I know many pilots who do not dip their tanks before every flight figuring the gauges are "close enough". Which may be true until they're not. Having something in iFly that makes them input important data and then monitor it may help reduce the "I thought I had enough" accidents out there. So I think it's a worthy goal and maybe could be perfected with beta testing and real world input from pilots using iFly. And I'd love for iFly to have a good, safety focused feature that ForeFlight doesn't.

 

[Cobra]

However I think a good approximation could be calculated from pilot testing and pilot entered data. For instance, EVERY time I fly I dip the tanks and measure gas amounts before engine start. Then at the conclusion of the flight I dip the tanks again and measure fuel used. I then use my TACH time to know average GPH. I make note of my cruising RPM, whether I leaned or not and what I leaned to, the altitude I flew at and the distance I flew. I'm not concerned about headwinds or tailwinds because it's the engine time and GPH that are the most critical and those aren't affected by winds. With this basic information I can pretty closely predict my fuel usage on another flight of similar variables (altitude, cruise RPM, amount of lean) with the time aloft increased or decreased by the winds to calculate how much fuel I'll need.

That's all good data, and I agree it could lead to useful approximations.

How many pilots do you think are as rigorous as you in collecting such data?

More to the point, what do you think the chances are that at least a few pilots will not be so meticulous?

It may not be perfect, as it does rely on accurate input from the pilot, but for those pilots who want to take the time to enter and update accurate information this could be a welcome assistance to flying.

Here's the risk I worry about:

A pilot who is not as meticulous as you takes a hack at his/her fuel on board and fuel burn. They're more optimistic than realistic. iFly uses the pilot's poor-quality data to draw constantly-updating "max range" rings on the display that are consistently well beyond their destination, making it look like everything's peachy. All of a sudden, the pilot runs out of fuel 10 miles short of their destination, because of their lousy data. They survive, get a lawyer, and sue the pants off of iFly. They win, iFly goes out of business, and everybody but lousy-data-pilot loses.

Am I overreacting? I dunno. Maybe this scenario is unlikely...but it's not impossible. This is a genuine business risk for iFly, regardless of how many disclaimers they put on the screen. If I were AP, I'd probably not take that chance.

I know I would sure love to have something like this to help me monitor fuel usage and fuel range alternatives. Especially the real time winds aloft calculations on fuel endurance would be worth the price of gold. And what would really be cool is if I input the fuel remaining at the end of each flight and iFly then accumulates the information captured on each flight and can become better predictive of fuel usage and range for future flights. But this would likely only be possible when AI is incorporated into iFly. Which I'm hoping someday it will.

I would love that too, but see previous comment above. This is why we can't have nice things.

 

[Cobra]

Having something in iFly that makes them input important data...

You're a programmer so you know that it is certainly possible to code an application to "make" the user input data.

But you can't "make" them input good-quality data.

Some fraction of users will just punch something in to make the input box go away, muttering under their breath. I suspect there will be significant overlap between the users who ignore the feature and the pilots who could most benefit from that feature.

 

[MDreger]

It seems iFly already does a lot of things based on data input by each of us pilots, all of which could go south if we put in the wrong data. While I question having a fuel remaining ring, it seems to me an option might be to have an instrument similar to the one that tells us when to start our descent.

Using the hourly fuel burn and fuel capacity input by the pilot, the program would keep track of flight time, and when that flight time hits a certain pilot specified time, the instrument pops up and says, and counts down "180 minutes of fuel remaining" That amount of fuel could be, depending on what iFly, the beta testers and users determine,

-time until tanks are predicted to be dry,
-time until the Day/Night, VFR/IFR minimum planned landing fuel exists.
-time until a pilot specified amount of fuel should exist. For example the pilot may feel most comfortable landing with one hour of fuel. The countdown clock would predict the time until that hour exists.

This instrument would remain invisible until the specified countdown time, then it would pop up, presumably alerting the pilot to compare the time on the instrument to the Estimated Time to the next Waypoint/Landing and ensure they are close enough to not be of concern.

 

[N2715D]

Such a ring would typically be beyond the visible area of the map when enroute. Too many variables to update range in flight (e.g. throttle setting and fuel flow).

 

[Randall Karstetter]

That's all good data, and I agree it could lead to useful approximations.

How many pilots do you think are as rigorous as you in collecting such data?

More to the point, what do you think the chances are that at least a few pilots will not be so meticulous?


Here's the risk I worry about:

A pilot who is not as meticulous as you takes a hack at his/her fuel on board and fuel burn. They're more optimistic than realistic. iFly uses the pilot's poor-quality data to draw constantly-updating "max range" rings on the display that are consistently well beyond their destination, making it look like everything's peachy. All of a sudden, the pilot runs out of fuel 10 miles short of their destination, because of their lousy data. They survive, get a lawyer, and sue the pants off of iFly. They win, iFly goes out of business, and everybody but lousy-data-pilot loses.

Am I overreacting? I dunno. Maybe this scenario is unlikely...but it's not impossible. This is a genuine business risk for iFly, regardless of how many disclaimers they put on the screen. If I were AP, I'd probably not take that chance.


I would love that too, but see previous comment above. This is why we can't have nice things.

Cobra,
Point very well taken. We live in a litigious society and everybody can sue for anything at any time and I think that's the real reason we can't have nice things sometimes. But I don't think that should stop us from trying. After all, you run that risk anytime someone uses iFly EFB even though you have a disclaimer to enter (which is worthless to a private injury attorney). You're probably right that not many pilots are as meticulous as me. I try my best to be the safest pilot I can be. But I think we can weed out those who are not, or choose not, to use the fuel ring feature properly which could get them in trouble. First, require them to input the exact amount of fuel in their tanks before selecting a flight plan if they want to use the Fuel Ring feature. Upon shutting down iFly, erase the starting amount of fuel in the Fuel Ring feature so that it won't work the next time the launch iFly. No accurate information, no fuel ring. Put the onus on them to give the program what it needs. If they want to guess, that's on them if they screw up, not on iFly. I think if you told a jury that iFly requires the pilot to input correct information before using a feature (or program) that would squarely put the responsibility on the pilot. Certainly iFly can't be responsible (or negligable) for stupid pilots. If the feature is disabled until and unless the pilot gives it accurate information to start with, then only those pilots who want to use it will use it and more than likely properly. I agree that once they give the program the starting fuel levels, and have entered the planned cruising RPM's and/or fuel flow, then the program will be depended on to get winds aloft and calculate fuel usage. But the program is doing nothing more than what the pilot could do by hand. And as with any piece of automation (autopilot, GPS route mapping, etc.) the pilot is still Pilot In Command responsible for the safety of the flight so the amount of blind faith a pilot wants to put into anything (Fuel Rings, etc.) is up to the pilot and whatever he/she uses (even Jeppesen maps and ATIS information) is the pilot's ultimate responsibility.

So I say, you can't fix stupid and you can't short helping good pilots who want to fly safer from being able to fly safer just because there are stupid pilots out there. Maybe discuss this with your legal department and see if there are things you can build into the feature that will reduce or mitigate frivolous lawsuits and then see about adding a feature that I think most pilots, instructors and insurance companies might welcome as a helpful pilot aid that could reduce accidents and fatalities. I really do appreciate you thinking about this and I hope I can help make this happen.

 

[Randall Karstetter]

Such a ring would typically be beyond the visible area of the map when enroute. Too many variables to update range in flight (e.g. throttle setting and fuel flow).

Yes, it wouldn't be visible at the start of the flight and probably not until near the destination depending on the sizing of the screen. But the user could shrink or expand the screen at any time to see it, if desired. But certainly having it there could be a quick visual aid. You're absolutely correct about variables which could change enroute. I think the thing to do would be to display the currently assumed RPM's or Fuel Flow and have the pilot edit those if they do something that changes these variables (i.e. tap a display and enter a new leaned fuel flow). If the pilot doesn't want to use this because it increases their workload, they shouldn't use it. Good luck pulling out your calculator and doing this on the fly (pun intended), especially calculating the headwind component, and thinking that is less workload, especially during an emergency. The ideal would be to have the plane download the tank readings and fuel flow but that will likely be down the road aways. I think it would be nice to at least beta test something like this to see if it's workable and how hard it would be to use. Maybe it won't fly. But maybe, some pilots might think it's the best thing since gliding rings. I'm still awestruck and grateful for those.

 

[Randall Karstetter]

It seems iFly already does a lot of things based on data input by each of us pilots, all of which could go south if we put in the wrong data. While I question having a fuel remaining ring, it seems to me an option might be to have an instrument similar to the one that tells us when to start our descent.

Using the hourly fuel burn and fuel capacity input by the pilot, the program would keep track of flight time, and when that flight time hits a certain pilot specified time, the instrument pops up and says, and counts down "180 minutes of fuel remaining" That amount of fuel could be, depending on what iFly, the beta testers and users determine,

-time until tanks are predicted to be dry,
-time until the Day/Night, VFR/IFR minimum planned landing fuel exists.
-time until a pilot specified amount of fuel should exist. For example the pilot may feel most comfortable landing with one hour of fuel. The countdown clock would predict the time until that hour exists.

This instrument would remain invisible until the specified countdown time, then it would pop up, presumably alerting the pilot to compare the time on the instrument to the Estimated Time to the next Waypoint/Landing and ensure they are close enough to not be of concern.

I like your idea and I think that is workable. It's also similar to what is already in use. But so is the glide rings. What I like about an estimated fuel ring (set to whatever reserve you want) is that it can instantly include/exclude possible diversion landing areas. I'm not thinking about it in terms of having enough fuel to make the planned destination. I think I've already got that figured out. I'm worried that if my planed destination closes then what are my options? I want to know quickly. So that is why I'd lile a fuel ring simila to the glide ring. But if that's not possible, I'd at least like something like you suggested. Anything is better than nothing.

 

[JoshSarah]

+1 on integrating manual entry fuel burn rings!!! I literally came to the feature requests to put this in. I understand it being approx - but would be a helpful approx - based on fuel burn in the aircraft setup page (and editable in flight plan).

Great discussion above. Let's do it!

Agree that bad data can be deadly - but we can already enter bad data on weight and balance.

Josh Brown
Greenwood Indiana
2006 Flight Design CTSW