Flight Planning: The missing item(s)

bobw75087

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When you begin a flight plan, there should be a box to enter the number of gallons of fuel already on board at departure.
((Of course, one could insert this into the weight and Balance, but (honestly) how often do you really do W&B? Especially when way under max.))
The first leg calculations are great, and you can mentally calculate how much you have minus first leg use, but wouldn't it be easier to just input FOB (Fuel on Board) when you begin the plan?//
And for that matter, when you tag a Fuel Stop, a box for how many gallons you add or plan to add. Both would provide more accuracy to the plan.
Assuming full tanks is not the same as having them.
 
This seems like a good idea, and also should be easy to implement, and present.
 
Hm. How do you know how many gallons are in a fuel tank unless it's full or empty?
 
Are you meaning what good does this capability do you if you don't know the fuel amount because you're not at your plane or you didn't write down a reading after the last flight?

My answer is that it would still be handy to be able to enter an estimate of your fuel (as you remember it) while at home doing flight planning. Or to fill in the fuel amount in the flight plan when you get to the airport so you can see how the plan is going to work out -- that is, if you need to fuel up before you go, or add a fuel stop.
 
Hm. How do you know how many gallons are in a fuel tank unless it's full or empty?
Many planes have well-functioning fuel gauges, despite the oft-repeated old wives' tale that "regs say gages only have to be accurate at full and empty!"

Many planes also have fuel totalizers built into their engine monitors that measure fuel flow to the engine and integrate it over time to keep track of fuel consumption.

Many planes have a "tab" that you can fill to and know an intermediate amount of fuel is onboard.

Many pilots also have a calibrated stick they can insert into the tanks to see how much fuel is left.

There are many ways to know how many gallons are in a fuel tank when it is between empty and full.
 
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You answered his question as it was literally written. I did too in my opening paragraph at first, but took that out as sounding like a smarta$$ answer. I assume he has a way to tell how much fuel is in his tank when not full or empty, or at least knows other pilots do.

[Edit: now it might sound like I'm dissing you. Not my intent.]

[P.S. They rewrote the reg because of all the misinterpretation. A sub-paragraph in §23.1337(b) used to say "Each fuel quantity indicator must be calibrated to read “zero” during level flight when the quantity of fuel remaining in the tank is equal to the unusable fuel supply...". They took that text out, rewrote stuff, and the pertinent part now reads "(a) Each fuel system must— ... (4) Provide the flightcrew with a means to determine the total usable fuel available and provide uninterrupted supply of that fuel when the system is correctly operated, accounting for likely fuel fluctuations"]
 
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Interesting stuff...I still fly legacy steam gauges and fuel gauges that bounce around w questionable accuracy... BUT, after the bugs get cleaned off, I use a Fuel Hawk gauge to stick the tanks (accurate w/in a gallon) and also check oil remaining. Both get noted, along w Tach & Hobbs, to go in the books. And be there when the next trip is planned. Pretty simple.
 
Ow! Ow! I'm smarting something awful!

iFly's Flight Plan already gives us the projected fuel consumption for each leg and the entire flight. If you know how much fuel is onboard before taking off, then you don't even have to do arithmetic to figure out if that will be enough. Just eyeball which amount is bigger, the projected consumption, or the amount on board. When you don't know or aren't sure, you top off the tank or do something else to estimate the amount on board if you can, and then do the comparison. I don't see any need to complicate Flight Plan so it can do the obvious.

The problem is the W&B calculator--and that hadn't occurred to me earlier. That's a cost of flying a simple airplane that has its one fuel tank right smack on the CG and plenty of reserve lift to take off with a 250 lb passenger and a full tank. (I simply don't take off with anyone who weighs more than that because the right stick between thick thighs makes crossing the controls for step turns almost impossible.) But when you have several fuel tanks jammed into various odd places in the airplane and who knows what else, it makes sense to have the W&B calculator doublecheck your eyeballs. So I retract what I said earlier.
 
If we added this to the Flight Plan, my first guess is to put it at the top, directly to the Right of the selected Aircraft, shown here (circled in red)

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That looks like the right spot to enter starting fuel qty. Can it be linked to W&B so an entry in one place changes it in the other? Or is there some reason to not link them? I think they should be linked but I haven't spent much time thinking about if there is an argument for not doing it.

I agree with Bobw that in the flight plan we also need the option on how much fuel to add at each stop to be able to factor in W&B and density altitude considerations along the route.

Tony
 
Would this fuel amount stay with the saved flight plan? I have saved plans that I simply load when I'm flying to/from those places. While they are all within a quarter tank or less, I would imagine that if I made regular long distance flights, it may be an error waiting to happen if my current fuel amount wasn't the same as it was when I made the flight plan.
 
That looks like the right spot to enter starting fuel qty. Can it be linked to W&B so an entry in one place changes it in the other? Or is there some reason to not link them? I think they should be linked but I haven't spent much time thinking about if there is an argument for not doing it.

I agree with Bobw that in the flight plan we also need the option on how much fuel to add at each stop to be able to factor in W&B and density altitude considerations along the route.

Tony
Our main priority here is 1-stop flight plans, btw, which is 90%+ of them. I don't think we'd make this value "too important" -- more of a note, useful for warning colors. Tying it to W&B setting seems correct, and is easy. If you edit WB, it'll change this value, and maybe vice-versa.

We would NOT store this with a flight plan. It would default to "full tank" unless changed by pilot or WB. Something like that.

I'm not sure if this feature request adds as more value than confusion. As is, it's pretty easy for pilots to see on the flight plan, fuel usage, and can do this simply math in their heads. So I'm not sure if we're solving any "pains" by adding something new to the flight plan like this.

I'd like to hear more discussion along these lines -- the costs of confusion (and more stuff on the page to look at) vs. the actual benefit to pilots.
 
Honestly, I don't think I'd ever use this. I've flown for 10+ years using flight plans that tell me how much fuel I'm going to consume, and how much fuel I need to carry to be legal for IFR flight. I use that info to help inform me on how much fuel I want to have in the tanks at takeoff. After that, I watch the gauges, watch the fuel totalizer, and watch the engine RPM settings to help monitor my fuel consumption en route.

I don't think I'd ever bother to populate the "starting fuel" qty in an iFly flight plan.

But I'm also just one person, and not necessarily a good representative of the rest of the iFly user community in this regard.
 
So far on my one and only long cross country from southern Florida to southern Texas I took off with full tanks at every stop but I was also solo. I think this feature would be useful on longer flights where I might have a heavier passenger and I need to limit my fuel by 4 gallons or so (about an hour's range for my plane; approx 22% of my total fuel load of 18 gallons) and it would affect where/when to stop. Seems like it would be safer/easier than trying to do the math that says subtract 4 from the remaining fuel at each waypoint. Agree that it doesn't need to be stored with a flight plan.

Maybe have the fuel setting default to the max capacity (like it does now) and let the user change it if they want?

Tony
 
Not sure that this is all that important. The flight plan fuel burn numbers are what we use to plan our flights - and always leave a reserve for head winds...
 
Brian: definitely the right spot, don't store w plan as it could be different each time. Still in favor of the add, and letting the plan do the math it does now, but with a much more accurate starting point.

FWIW, if you can always put it away w full tanks and that works for you, great. But we always keep it below max as "crew size may differ😉", and the last thing I want to be doing before a flight is draining tanks to make GTOW.
 
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