Need help with fuel planning

[japascoe 98]

I find fuelplanner relatively accurate usually. Obviously it's not hugely precise, but it usually arrives in the right ballpark. One thing I noticed is that your CI of 80 is rather high. CI will certainly affect fuel burn as high CI = high speed = high fuel burn. I usually have a CI of about 15-20. Having a CI of 80 will make you burn a lot more fuel, which might be causing your problems.

As others have mentioned the ' reserve' number you enter in the FMC is used to say: 'warn me if I will be landing with less fuel than this, based on your current prediction.'

[Spook 96]

This is what i have scribbled down from the Tut:

 

2,200 lbs per 100nm

Add reserves off 5,500 lbs

Multiply by 0.05 for contingencey fuel

 

APU burns 4 lbs per min

Taxi burns 27lbs per min

 

+Extra motion lotion @ captains descretion..i usually add 1000lbs.

 

Seems to work good, altho probably completly wrong.

[Gregg_Seipp 573]

Ok guys, you've given me a lot of useful information and a lot to think about.  I have to go do my day job but I'll try to get some time tonight to try it out.

[lassekronborg 43]

Look at this topic on the forum.

 

http://forum.avsim.net/topic/405110-free-alternative-to-topcat/

 

The sheet offers help with fuelplanning. It does performance calculations as well.

It might look like a very busy sheet at first. But don't panic. It is quite intuitive and easy to use.

 

Regards

Lasse

[Airbusman330 300]

 

 

Ouch, yeah.  It doesn't know weight, altitude, winds aloft, or anything.  It's a nifty tool for your average simmer flying the default stuff, but it's nowhere near as realistic as it should be for other purposes.

 

I never have an issue with it when getting fuel numbers for the NGX, I really hate flight planning so while the numbers are not spot on it does give me plenty of fuel to get there and I make a quick visit to flight aware for the route. 

[scandinavian13 5,192]

 

I never have an issue with it when getting fuel numbers for the NGX, I really hate flight planning so while the numbers are not spot on it does give me plenty of fuel to get there and I make a quick visit to flight aware for the route. 

 

Well there's an issue here of expectations, though.

 

You expect that rough estimate to give you enough to get there using its simple calculations.  As long as you understand that those numbers will be rough at best, then you're more prepared to dismiss fuel issues as not a problem with the plane, or the FMC.

 

The problem is where people are getting mediocre, at best, fuel numbers from all kinds of sources, and expecting the FMC to ingest it and not give them trouble for it.

 

Additionally, it's almost less of a hassle to get your fuel numbers from the FMC using the method in tutorial 2.  As I said earlier, it's not so much the extra effort, it's breaking the bad habit of running off to get weak data because you're used to that method.

[mosteen 111]

I use FSCalc for iOS together with winds aloft predictions from AS2012. Pretty much bang on, in FSCalc you decide what "rules" should apply as your default, for example "Alternate+45 minutes", Taxi=x minutes, holding=x and so on. You enter your city pair and alternate, ZFW and winds, and you're done. It has profiles for 737 and MD-11.

[Airbusman330 300]

Well there's an issue here of expectations, though.

 

You expect that rough estimate to give you enough to get there using its simple calculations. As long as you understand that those numbers will be rough at best, then you're more prepared to dismiss fuel issues as not a problem with the plane, or the FMC.

 

The problem is where people are getting mediocre, at best, fuel numbers from all kinds of sources, and expecting the FMC to ingest it and not give them trouble for it.

 

Additionally, it's almost less of a hassle to get your fuel numbers from the FMC using the method in tutorial 2. As I said earlier, it's not so much the extra effort, it's breaking the bad habit of running off to get weak data because you're used to that method.

Ive used fuel planner for most of my flights and never ever had an issue and the fuel numbers never went below 6-7 thousand pounds upon landing, the only time I had an problem was when I used the wrong destination icao in fuel planner but the mistake was caught before filling up. My main issue with most flight planning tools is that they are too detailed and you can't finish your plan within 10 seconds, the NGX gives the v speeds and as for other planes like the Q400 I always rotate at the same approximate speed since the weights are never changed aside fuel.

[Gregg_Seipp 573]

Well, I ran through the 10 pages of fuel planning in the second tutorial (yikes!). 

 

--Cost Index 30

--standard flight plan and altitude and with my alternate as KONT. 

--assumed standard APU burn (30 minute) and taxi time (10 minute)

--a 30 minute hold at both KLAX and KONT.

--0 extra fuel

 

This came up with 10.8 for total fuel needed. 7.3 trip fuel and 3.5 reserves. 

 

I have to admit I had to go back and forth through it a couple of times and ended up creating a (crappy) spreadsheet because I can easily see myself making a mistake.  The good part about doing it that way is that it calculates expected fuel at destination based on what you put in (wind, temperature, altitude, route, etc.) and what the aircraft knows about itself.  So, you pull those expected fuel at destination numbers in and do the calculations. 

 

According to Topcat the trip fuel would have been 5.2 (It doesn't know winds aloft, cost index and didn't change when I specified an alternate).  I doubt it had holding so 5.2 + 2.5 = 7.7 trip fuel.  Not that bad if you know that there's no holding in their figure nor alternate in there.

 

According to flightplanner.com the trip fuel would have been 4.3.  It specified a reserve of 6.1 but didn't know what my alternate was so I put in a trip from KLAX to KONT and it gave me 2.4.  Probably no hold time in either of those so 4.3+2.5 = 6.8 trip fuel, 2.4+2.5 = 4.9 alternate trip.  11.7 total fuel needed.  Not bad if you add holding fuel and do a separate alternate calculation and add the hold fuel for the alternate.

 

A back of the envelop using the 2200 lbs per 100 miles would have given 4.9 for trip + 2.5 holding = 7.4 trip fuel, 1.3 + 2.5 = 3.8 alternate fuel for a total of 11.2 total fuel needed.

 

This is for a very short flight so I'll have to try it again with something more pragmatic in length.  I'd be curious what FSCalc says. 

 

When I was done I left trip fuel blank and just put in reserves as per the tutorial.  I see now that the trip fuel is for special circumstances and you don't have to put it in.