Usage

The program can be started by clicking one of the shortcuts created during the installation. When starting for the first time, you need to set up the location of the navigational databases. See the Setup section for more information.

After the program has loaded all data (this may take a few seconds on a reasonably fast machine, i.e. on one that is capable of running FS9 :), the main dialog is displayed. It contains the usual menu bar, and three tabs.

At the bottom you can select the unit of weight (sorry, “mass”, in fact, but “weight” is used all over the program) for the displays.

On the Flight tab, you can specify the most important data about the flight for which you wish to calculate the amount of fuel needed. The data to be entered is rather self-explanatory, and there are also tooltips to help. The cruise levels can be given with a prefix. The prefix A denotes an altitude in feet, F is for flight levels in hundreds of feet, S is for flight levels in tens of metres and M is for flight altitude in metres.

The Route field allows the freetext entry of the flight route. It may consist of waypoints and airways between waypoints. Waypoints may be extended with speed and/or altitude change information after a slash following the waypoint’s name. The altitude change information is used by the fuel calculator, but all other information is ignored. For example, true airspeed is taken from the aircraft’s performance data, and that is used regardless of any speed changes specified.

Waypoints can be given using geographical coordinates. In this case they must begin four or six digits specifying the latitude. The first to digits are the degrees, followed by two digits of minutes, optionally followed by two digits of seconds. The digits must be followed by either N or S specifying northern or southern latitude, respectively. Then should come another five or seven digits. The first three specify the longitudinal degree, followed by two digits of minutes and optionally two digits of seconds. The latitude digits must be followed by either E or W for eastern or western latitude, respectively. The seconds must be given in either none of the values or in both of them.

Next to the ICAO code of the alternate airport you can see a Find button. Pressing it brings up a dialog that helps to find an airport within a certain range from the destination airport. The minimum and the maximum of the range can be given. The search is started by pressing Start search. It may take a few seconds, and then the airports found are listed in the table below sorted by their distance. By selecting an airport and pressing Use selected or double clicking on an airport you can put that airport into the field for the alternate’s ICAO code.

When you have entered all information about your flight, change to the Weights & Summary tab. Under the Fuel heading, you can specify some “fixed” fuel amounts. The taxi, holding and minimum landing fuel amounts are taken from the aircraft’s data, but if you click on the Use default button, so that it is not pressed in, the corresponding amount can be specified for the current flight.

The Weights and Summary areas contain computed values, that cannot be changed. Some of these values are greyed out, meaning that they have not yet been calculated.

By clicking on the Recalculate button, the amount of fuel is calculated. It will result in the missing values in the two areas mentioned above being filled up. If any of the weights exceeds the limits, it is highlighted in red. The Summary area contains some (hopefully) useful information about the time used for the various stages of the flight, and some other data.

If the amount of fuel is calculated, the Schedule tab contains a table of the waypoints of the flight. For each waypoint some data, including distances, courses, etc. are displayed. If you hover the cursor over a row in this table, a popup window is displayed, which contains the coordinates of the waypoint and information about the FIR which it can be found in. (The FIR information is a bit rudimentary at present.) If the altitude at some waypoint is invalid according to the FIR’s flight level rules (RVSM, metric, whatever), it is displayed in red. If no information about the FIR is available, the altitude is displayed in orange.

You can also connect to Flight Simulator, if you want some data to be recorded for each waypoint. This way the accuracy of the fuel calculation can be checked, and you can also make forecasts during flight about how much the deviation will be.

The menus

The File menu contains the following items:

  • New: create a new flight by resetting all data.
  • Open: open a saved flight.
  • Save: save the current flight. If no filename has been given, it is asked, otherwise the original name is used.
  • Save As: save the current flight with a new name.
  • Save Schedule: save the current schedule displayed on the Schedule tab. The table is saved into a text file.
  • Export: this a submenu allowing the user to save the flight in various formats: Flight Simulator flight plan, PMDG route file, iFly flight plan, SB3/FSInn flight plan and vasFMC flight plan. There is also a Quick Export menu item, which exports the flight plan into those formats whose corresponding target directory and the Include in quick export option is set without asking any questions, using the default directories and naming rules.
  • Quit: quit the application.

The Tools menu contains only two items, Preferences and Performance. Preferences displays the setup dialog discussed in more detail in the Setup section. Performance displays the performance data management dialog discussed in the Performance data section.

The View menu also contains only one item, Show Log. If it is selected, a new tab with the title Log is displayed. It contains some printouts from various parts of the program, which may be needed for debugging.

Fuel calculation method

The program calculates the fuel consumption using performance data. These data can be found in the aircraft subdirectory of the application. There are two formats used:

  • The files with the .bada suffix contain performance data from Eurocontrol’s BADA files. Unfortunately these data no longer seem to be available publicly, though they were in the summer of 2007 when the project was started.
  • The files with the .perf suffix contain measured performance data. See the section Performance data on how to measure performance data for any aircraft.

The amount of fuel is the sum of the following:

  • Taxi fuel for taxi out
  • Trip fuel: climb, cruise and descent from the departure airport to the arrival airport including the procedures if specified. The average cruise wind is taken into account for the cruise part. The extra fuel is also added to this part.
  • Contingency fuel: 5% of the trip fuel.
  • Alternate fuel: climb to the alternate cruise altitude, cruise, and descent from the arrival airport to the alternate airport.
  • Holding fuel: the specified holding fuel.
  • Minimal fuel: the specified minimum landing fuel

If there are altitude changes during cruise, those are taken into account, albeit in a simplified form: the aircraft is assumed to fly one altitude till the alitude change point, and the new altitude afterwards. In other words, cruise climb or descent is not calculated, but probably it is not significant. If it is, you can still add some estimate to the extra fuel.

The aircraft’s weight loss is taken into account for all calculations, so an approximation method is used, which might take a few seconds to complete.

The FIR data

The FIR layout data is converted from ServInfo’s fir.dat, and stored in the installation directory in a file also named fir.dat with some additional data, such as the FIR name and the flight level rules for that FIR. However, the flight level rules data is present there only for a few FIRs (mostly in Europe), so you may need to edit this file if you would like to use the altitude checking functions when flying in other parts of the world. It is planned to provide a GUI editor within CalcFuel, which would also automatically notify the author of any changes, so that the master copy of the file could be updated.

Setup

Since CalcFuel computes (among other things) the distance of the flight, based on information such as the departure and arrival airports and the route, it needs a database with navigational data. Therefore the location of the navigational database must be given to it.

As of this writing, CalcFuel uses the PMDG AIRAC database, that can be obtained from Navigraph. Unfortunately, the data is not for free (though not too expensive either), but older versions can be found in the AVSIM file library.

You can use the Preferences dialog accessible from the Tools menu to specify the directories where the navigational data (usually C:\Program Files\Microsoft Games\Flight Simulator 9\FMCWP\NavData) and the procedures (C:\Program Files\Microsoft Games\Flight Simulator 9\PMDG\SIDSTARS) can be found. These can be given in the first two input fields under the AIRAC directories heading. The Browse… button next to the input fields allows you to browse the directories on your system to select the desired one. If the navigational data directory changes, the navigational database will be (re-)read from the disk. However, if you change the procedures directory, it affects only airports that are used first after the change.

It is also possible to select an extra navigational directory. It should contain files named airport.dat and wpNavAPT.txt formatted as the corresponding files used by PMDG. If these files are present, the loaded navigational database will be augmented with their contents.

The files have a strict format. Lines with comments start with a semicolon. Lines containing airport data have the following format in airport.dat:

characters 0-3:
the ICAO code of the airport
characters 4-13:
the latitude of the airport in degrees, with north being positive
characters 14-24:
the longitude of the airport in degrees, with east being positive

The lines of wpNavAPT.txt containing runway data have the following format:

characters 0-23:
the name of the airport (not used)
characters 24-27:
the ICAO code of the airport
characters 28-30:
the name of the runway
characters 31-35:
the length of the runway in feet (not used)
characters 36-38:
the direction of the runway in whole degrees (not used)
characters 39-48:
the latitude of the runway threshold in degrees, with north being positive
characters 49-59:
the longitude of the runway threshold in degrees, with east being positive
characters 60-65:
the ILS frequency for the runway if any with 2 decimal digits. 000.00 if the runway has no ILS. Not used.
characters 66-68:
the course of the ILS (not used)
characters 69-73:
the altitude of the runway threshold in feet

The Preferences dialog also allows the specification of a number of other directories. These are the following:

  • Flight save directory: this directory is offered as the default one when saving and loading flights.
  • Schedule save directory: this directory is offered as the default one when saving and loading schedules.
  • Flight Simulator flight plans: this directory is offered as the default when exporting the current flight into Flight Simulator’s flight plan format. If you select the Include in quick export checkbox, then the quick export option will save the flight plan into this directory. This directory is usually C:\Documents and Settings\<user name>\My Documents\Flight Simulator Files.
  • PMDG FMC route: this directory is offered as the default when exporting the current flight into PMDG’s FMC route file format. If you select the Include in quick export checkbox, then the quick export option will save the route file into this directory. This directory is usually C:\Program Files\Microsoft Games\Flight Simulator 9\PMDG\FLIGHTPLANS.
  • iFly FMC flight plans: this directory is offered as the default when exporting the current flight into iFly’s FMC flight plan file format. If you select the Include in quick export checkbox, then the quick export option will save the route file into this directory. This directory is usually C:\Program Files\Microsoft Games\Flight Simulator 9\iFly\737NG\navdata.
  • SB3/FSInn flight plans: this directory is offered as the default when exporting the current flight into Squawkbox 3’s and FSInn’s flight plan format. If you select the Include in quick export checkbox, then the quick export option will save the flight plan file into this directory.
  • vasFMC flight plans: this directory is offered as the default when exporting the current flight into vasFMC’s flight plan format. If you select the Include in quick export checkbox, then the quick export option will save the flight plan into this directory. This directory is usually C:\Program Files\vasfmc\fps.

Performance data

Overview

CalcFuel can measure the performance data of aircraft and use the results of those measurements to calculate the fuel requirements. The performance files (with a .perf extension) can be found in the aircraft subdirectory of the program, along the corresponding .acft file that describes the other data of a certain aircraft type. Try to find a .perf file (e.g. dh8d.perf) and have a look at it while reading the description below.

The .perf files can contain comments that start with the hash (#) character and extend till the end of the line. The files have a number of sections, starting with a line containing the section’s name in square brackets.

The can be one ore more [climb] sections. They describe a data sequence measured during a climb, preferably from close to sea level to the service ceiling of the aircraft. Each line after the [climb] word gives the measured data for a certain altitude: the weight of the airplane as well as the time elapsed the distance flown since the start of the climb. The latter two data are usually 0 for the first measured altitude, which is usually 1000 feet. The lines are ordered by altitude, and are recorded for every 1000 feet.

There are usually several climb data sequences for different weights. The program interpolates between the data using the aircraft’s weight. Therefore it is recommended to have at least 3 sequences: one for low weight, another for medium and a third one for high weight.

Similarly to the climb data sequences, there are also descent data sequences, started by the [descent] word. The same data is recorded, but the lines are ordered in reverse order according to the altitude.

For cruising, different kind of data is recorded. The file contains exactly one [cruise] section. The lines in the section start with an altitude. It is followed by at least one data triplet, the members of which are: the weight of the aircraft, the true airspeed and the fuel flow. There can be several triplets for different weights, so that the program could interpolate between them, just as it does for climb and descent data. It is recommended to have data recorded for every 1000 or 2000 feet altitude, and for three different weights, like in case of the climb and descent data.

Managing measured data

By selecting the Tools/Performance menu option, the CalcFuel Performance Data Editor window is displayed. It has its own menu bar with File and Help menus. The File menu contains the usual file creation, opening and saving options, by which you can create, open or save performance files.

The windows has three tabs: Climb, Cruise and Descent.

The Climb tab displays one data sequence at a time. You can switch between sequences by selecting the sequence number after the Sequence # label. The sequences are simply numbered from 0 upwards. If you click on the Create New button, a new, empty sequence is created.

There are the following buttons next to the sequence data display:

  • Measure data: it starts a measurement. First you have to enter the target altitude. If you reach this altitude during the climb, the measurement will end automatically.

    After entering this value, the Measurement Progress dialog is displayed. The program first connects to Flight Simulator, and when this is successful, the following message is displayed:

    When you are rolling on the runway, you can press the Start button. The program then records the current altitude, and will start the measurement when you pass the next multiple of 1000 feet during climbing. When this happens, the progress bar becomes alive, and will show the current altitude. Data is recorded for every 1000 feet of altitude.

  • Clear data: clears the current sequence, but the sequence is not deleted. This is useful, if you want to re-record a sequence.

  • Delete sequence: completely deletes the current data sequence.

The Descent tab is similar, except that data is displayed in reverse order according to the altitude, and during measurement, the measurement starts at the largest multiple of 1000 feet below the current altitude and, of course, the aircraft is expected to descend during the measurement.

The Cruise tab is quite different. It contains a combo box at the top from which you can select all those altitudes that have corresponding measurements. You can select one ore more rows from the table containing the data, and then click Clear selected to delete those data.

If you click the Measure data button, the program displays the Measurement Progress dialog, and tries to connect to Flight Simulator. If this succeeds, the following message is displayed:

If you do accordinly, and click the Start button, the program reads the current altitude, and rounds it to the nearest 1000 feet for the purposes of recording the data (this fact is displayed). Then it reads the weight, the true airspeed and the fuel flow every one tenth of a second for 30 seconds.

When the measurement is done, the samples are averaged and that becomes the measurement result, which is recorded in the table for the altitude.

All measurements can be interrupted at any time by pressing the Cancel button.

Note: aircraft information, including performance data is read when the program starts up. When you open, modify and save the performance file in the Performance Editor window, the changes are not reflected immediately in the calculations made by CalcFuel. You have to restart the program to use the modified data. (This is planned to be fixed later.)