Hi,

 

I have recently purchased the MD-11 and I can say it is one stunning aircraft to fly. I have been using online fuel planning websites such as http://fuel.aerotexas.com/ to calculate my load fuel which I have then entered into the load manager to get the weight information. However, the thing that annoys me with these websites is you can't input your cargo weights. For example, I could be loading the aircraft with full cargo where the website gives me fuel calculations for 33% cargo; would my trip fuel be the same irrelevant of the cargo?

 

My best hope is to either locate a proffesional fuel planning utility or do it myself. I found the following formula when searching the web earlier.

 

Loading Fuel = (Fuel base amount + (Distance * Fuel Burn Factor))

 

I'm guessing here that Fuel burn factor is average burn rate which I believe in the MD-11 is 31.6.

 

And I'm also guessing that Fuel Base Amount is landing fuel? If so, for an example flight from Manchester to Frankfurt, I would have the following information:

 

Fuel Base Amount = 40,000LBS

 

Distance = 570.3NM

 

Fuel Burn Factor = 31.6

 

When using the formula I finish with a loading fuel of: 50,421.48lbs

 

I must then calculate wind component adjustment. I find the average heading, let's call it 120. I get the wind information for my cruising altitude of lets say FL350. Imagine the wind direction is 270 and wind speed is 65knots. We use the following formula:

 

 

Cos (Average heading - Wind Direction) * Wind Speed Now substitute the values.

 

Cos (120 - 270) * 65

 

This gives me a wind component adjustment of: -56.3nm

 

This basically means that I have a tailwind which is going to take 56.3 miles away from my air distance, which in turn saves me fuel. If the number was positive, I would have a headwind. I would then subtract this from my previous air distance of 570.3nm giving me 514nm. I would then recalculate my loading fuel using this distance.

 

 

 

 

This fuel calculation looks pretty accurate. However, it doesn't have any other factors such as payload information.

 

 

What I would really like to know is a formula that tells me how to calculate loading fuel using this fomula, wind component adjustment formula, and something that includes payload information. I hope this has also given you some help with manual fuel planning.

 

 

Thanks in advance.

 

Matthew

Hi Matthew,

 

I don't have one formula for you, however I have some formulas jamed togetter and with the addition of a little bit of PHP for you. Here you can calculate fuel for the PMDG MD-11. I have done it in my free time, and it is also free to use. Just bunch in the data, and you will get an hopfully correct amount of fuel needed. ;)

 

Best regards

 

Jonathan

Hi Matthew,

 

I don't have one formula for you, however I have some formulas jamed togetter and with the addition of a little bit of PHP for you. Here you can calculate fuel for the PMDG MD-11. I have done it in my free time, and it is also free to use. Just bunch in the data, and you will get an hopfully correct amount of fuel needed. ;)

 

Best regards

 

Jonathan

 

 

Hi Jonathon. Thank you very much for your reply. The link you gave me is probably the best thing I've come across since I started flying the MD-11. Thank you very much. I will still continue to use my formulas because I believe it is always good to know them in case during flight I had to do some calculations but this program really does help.

 

All the best.

 

Matthew

I just plugged in the details from one of the flights I did the other day... It is pretty good.. quite close to what LIDO told us to take!