performance calculation worksheet

Hi,

since I didn't found a proper tool in the internet I created an Excel worksheet to let the computer calculate the take-off and landing performance for the ATR 72-500.  The data is taken from the Flight1 ATR 72-500 Orientation Manual and the calculations follow the instructions given there.You can download the file via

http://people.freenet.de/thilo.arndt/20050901_F1_ATR72-500_P erformance_Calculation.zip

Many calculations are implemented in Excel VB. So if you want to use this sheet you have to enable macros.

The file is not protected. Feel free to use it as needed. You can even implement your own calculations. My intention is to use it the file as a starting point for discussions about how to do all these calculations and whether all this can be automated.

rgds

lilo

buffi,

let me think a bout it. This is probably what most of European flight sim enthusiasts would like to have. Hm, should have been aware of this prior of mixing all the units. Requires some clean up and more  generic functions...

In the mean time and as a work around you can convert directly within the worksheet. You don't have to do this by hand. If you want to convert ° C to ° F just type in:

   =ToFahrenheit(TempC)

where TempC is the temperature in ° C. To convert kg into lb you can type in:

   =WeightKg * KG2LB

where WeightKg is the weight in kg. The constant KG2LB is an alias for a cell in the sheet "Conversion" which is one of the last sheets in this file. If you have the Excel Analytics module installed which is not the default you can also use the special conversion function "CONVERT" ("UMWANDELN" in German Excel).

rgds

lilo

Amazing!

In a single-handed blow you made my efforts to create a TALD-Calculator useless. I am impressed! This is 100 times better than what I would have been able to come up with.

Did you have time to implement the complete obstacle computation, yet?

And if you also decide to include the T/O and Landing Torque calculation, this thing will be perfect. I know: You said "When landing I am not interested in the torque at all, since I use the EEC/PEC". But the torque becomes very interesting in case you need to do a takeoff in hot+high conditions or need to do a go around. In that case you will shred your engines quite quickly. Try explaining that to the insurance agent: "Listen up, mate. I am sorry, but torques really don't interest me...".


Great Job! I will use this instead of my paper version from now on...

p.s.: I also would kindly ask you to include a easier converter or clean it up a bit, so that the units are no longer mixed. Lot's of work, I know...

p.p.s.: Maybe I found a little bug? I tried entering values that would make me NOT exceed the MTOW (ZFW=42184lb, Fuel 4000lb, Zp=450ft, LC3=9599ft). Then I selected "Runway Condition = 6 - compact snow". the TOW-Limit immediately jumped to "EXCEEDED", which is good. But when I changed the runway condition, the TOW remained exceeded, which can not be correct. Am I doing something wrong?

p.p.p.s: A little feature request... The spreadsheet prints out the value "Airport pressure altitude", but that is misnamed. I only gives you the value to add/substract from the real altitude. Would it be possible to also print out the actual Zp?

buffi,

let's do this by example. At the Take-Off Performance sheet there is the input field for OAT which is cell D8. If the field would accept ° C you would simply type in

Outside Air Temperature (OAT): 25

Actually, it doesn't. So you have to apply my workaround and enter

Outside Air Temperature (OAT): =ToFahrenheit(25)

You finish th input of the formula by pressing [ENTER]. You can also select the cell and then enter the formula "=ToFahrenheit(25)" into the formula input field fx right above the sheet.

Now enter the ZFW in cell D3. To convert 21,5 t into lb type in:

Zero Fuel Weight (ZFW): =21500*KG2LB

and finish the input by pressing [ENTER]. Do it in the same way in cell D4 for entering the fuel weight of 1500 kg:

Fuel: =1500*KG2LB

and press [ENTER]. That's it. If you still have problems send me a PM and I will send you a file containing sample values.

Good news: You don't have to wait for long. I already started to implement user defined units of measure. Once I'm finished I will publish a new URL. I can't promise anything but I think I'm finished until end of this week.

rgds

lilo

Hi Lilo,

I´m in a hurry now. Only looked for an answer... Will try that later when I´m back.

Thank you for your help. And knowing that you work on it by yourself relieves me...

Hi,

version 1.1 is available. Donwload the file via

http://people.freenet.de/thilo.arndt/F1_ATR72-500_Performanc e_Calculation_v1.1.zip

New functionality:

• user defined units of measure: The units of measure can now be changed by clicking on the button "Preset Metric" or "Preset Imperial". You can also change the unit for individual measures by selecting the units from the dropdown listboxes. I recommend to change the units according to your preferences the first time you open the file. After that select the "Take-Off Performance" or "Landing Performance" sheet" and save the file under a new name. Make this new file read only and use it from now on.
• Check of ZFW: MZFW was already on the "Limitations" sheet. So that was easy.
• Check of max. obstacle height: A warning "Too high!" will appear right beside the input fields if the obstacle height exceeds the maximum allowed obstacle height for the given distance.

Bug fixes and changes:

• Pressure altitude: The meaning of the term "pressure altitude" has been clarified and a proper formula was implemented. The change of the altitude and the airport pressure altitude are now displayed in separate fields.
• Take-off weight according to LC3: The calculation resulted in 0 if snow or ice was selected and the temperature was above 5 ° C. The code now catches this inconsistency by setting the temperature to 5 ° C for further calculation.

rgds

lilo

Amazing.... absolutely A-MA-ZING!! Thile, you are the genius of Excel! I tried it, and this thing is brilliant!

I found some more little bugs:

1) When I select a "Runway Status", which results in limiting conditions, or weather data which results in icing conditions: This won't change back to normal/NL once you select different values. Don't know why.

Could this maybe be solved by creating a "Force calculation now (Use this button if the excel-sheet refuses to accept changes which would lead to different results)"-button?

I also did NOT find this strange "problem" in the landing calculation.

2) Remote Obstacle Distance (using metric units): Doesn't accept the value "0". There is an error message "The entered value is invalid. An other user limited the value that can be entered into this cell." ("Der eingegebene Wert ist ungültig. Ein anderer hat die Werte begrenzt, die in diese Zelle eingegeben werden können"). It only accepts values bigger than "1".

3) Not a bug: You put very handy links on each page, to make navigation really easy. But I miss a button/link on the first page, which will lead you to the units-of-measure-setup or directely to the calculations. Personally I would like to have 3 links:

* Set up units of measure (+Print out the actual setting)
* Go directely to Takeoff calculation without setting up units of measure
* Go directely to Landing calculation without setting up units of measure

Thank you for your hard work! What you achieved, is absolutely amazing!

Hi,

the latest version is available and can be downloaded via

http://people.freenet.de/thilo.arndt/F1_ATR72-500_Performanc e_Calculation_v1.2.zip

New functionality:

• Qick links were placedon the first sheet to make navigation more intuitive.

Bug fixes and changes:

• The validations at the input fields for obstacle distances were removed. The popup notes describe what should be entered into which field.
• The calculation of the obstacle decrement has been fixed. The unit-of-measure-redesign caused the calculation to return wrong values. If the distance for a close obstacle is specified greater than 1 km the calculation now internally treats it as remote obstacle (and vice versa).

rgds

lilo

buffi,

that's all no mystery. As you have noticed there are almost no formulas of the type

=D4 + 1,34 * E17

in the cells. And there is a good reason for this: It is by far too complex to express the calculations of all the parameters in ordinary formulas. There are too many conditions to be checked and data tables to be searched for values. So I created Excel Visual Basic (VB) functions which I then call from within a cell by putting statements like

=GetObstacleDec(...

into the cell. The function "GetObstacleDec", like all the other functions I created, can be accessed by starting the Visual Basic Editor (press [Alt] + [F11]) and opening the module modMain. In fact, I strongly encourage everyone to do this. VB is not that difficult that it would be totally impossible for a novice to read the code. As already pointed out my intention was and is to provide a basis for productive discussions about the correct calculation of all these parameters.

My basic idea was to keep everything as simple as possible without loosing flexibility. So I created a new Excel file and typed in all the data tables as published in the F1 ATR 72-500 Orientation Manual. The method of going through all these tables and diagrams step by step is implemented mainly in the VB code. Especially the search for a certain value in a data table has been kept highly generic. The function "GetValFromIsoLine(...)" - which I regard as the heart of the whole thing - allows search for values in any table whatever data it contains. In addition, interpolated values can be calculated for input which doesn't exactly match a value in the data table (for example: find VMCA for pressure altitude = 354 ft, temperature = 27 ° C). The mathematics behind this has something to do with planes and lines in the three dimensional space. When it comes to take-off data (weight, V1, V2) we have to deal with four dimensions which makes it even more complicated because the data is spread over multiple sheets. Well, one could regard the "NORMAL"/"ICING" condition as a fifth dimension . But that's theorizing...

rgds
lilo

lilo,

Thank you for the excellent performance calculation sheet, it works great!