It's been about a month since the first post on FDR readout using Matlab. Now, allow me to show and to give you the application. I called it aPENGAMAT. In Bahasa Indonesia, this is Analisis Penerbangan dan Keselamatan. In English, it could be Flight Safety Analysis. Yes I know, the name of the software is quite a big deal while this initial release is no more than a very simple readout process. I have a dream (well, only a dream for now) that this software could also be used as a real flight safety analysis such as AirFASE. In fact, software routines are basically mimicking AirFASE. OK, let me introduce you. And at the end of this article, I'll give you the software ;)
Since this is based on Matlab 2008a Engine, you will need to instal Matlab Compiler Runtime (MCR 7.8). It's funny enough that I could not find download page in Mathworks site!
Edited: It seemed Mathworks would not allow any public reference for downloading it. You may need to purchase a Matlab license to obtain MCR included. Thank you Sumandari for MCR Installer link.
If you click the executable file, the main windows would be like this.
Just like the AirFASE routine goes on, there will be 1+3 simple step to be able to read FDR file. At first, you will need to setup -a so called dataframe layout that is customized for each aircraft. Ask for it to airline or manufacturer of the aircraft. May be you are wondering now, what is the dataframe layout? Well, you can read a general explanation here and here. If you have access and/or capability, just go to ARINC site and purchase ARINC 717 specification document. It will cost you a couple hundreds US dollars ;)But let me give you one quick example what is the dataframe layout and how to define a flight parameter conversion into database. Let me pick a parameter called HEADING ATTITUDE. An aircraft's heading is the direction that the aircraft's nose is pointing. It is referenced by using either the magnetic compass or heading indicator, two instruments that most aircraft have as standard. Using standard instrumentation, it is in reference to the local magnetic north direction. True heading is in relation to the lines of meridian (north-south lines). The units are degrees from north in a clockwise direction. East is 90, south is 180 and west is 270 degrees. Operational range would then be from 0 degree to 360 degree.
Now, from a dataframe layout document, it is stated that the HEADING PARAMETER is stored in word 28, all subframes (1-4), and taking up 10 of 12 bits, ie: bit 3 (LSB) to bit 12 (MSB). See picture below. This parameter location is marked blue.
Now, the conversion function from raw data into engineering unit would be:
EU(DEGREE) = operational_range/bit_len^2 * RAW(DECIMAL)
From the figure above,RAW = 1111100100 (BINARY) = 996 (DECIMAL)
Knowing the operational_range is 360 degree and bit_len is 10, the engineering unit would be:
HEADING (DEGREE) = 360/10^2 * 996
HEADING (DEGREE) = 0.08 * 996
HEADING = 350.156 DEGREE
This generic rule also valid for some flight parameters, such as pitch and roll attitude. Read the rest of the aircraft dataframe layout document. Now, we are ready to input it into DFL database. See figure below.
To be able to decode the FDR file, this program will try to communicate with dataframe layout database. And since I only have knowledge on Microsoft Access, we will keep in-touch with this closed-source software. To connect aPENGAMAT with Access database, open your Control Panel -> Administrative Tools -> Data Source (ODBC). Obviously, it is for Windows only.
Click "Add" to create new data source -> choose "Microsoft Access Driver (*.mdb,*.accdb)" -> click "Finish".
In "Data Source Name", type DFL. It must only be DFL though. In Database group click "Select...". Now, select DFL.accdb (this file is given. scroll trough the end of this article to download). Click "OK." Now, our dataframe layout database is already registered to Windows. Well done!
Now, we need to build m-file dataframe layout. From main window, click "Build DFL". Depending on your dataframe layout database, a input dialog will appear.
Choose a related dataframe that you want to use to read the FDR file. Then, we need to build -a so called intermediate file. This is no more than a mat file which is already structured in frame-subframe-word as specified in ARINC 717. Click "Build Intermediate" to proceed.
OK. Now, take a look at "Word: 64". It is the value of word per second that is effective to FDR file. Other value would be 128, 256 and 512 wps. Recent Boeing aircraft such as Lion Air B737-900ER with a tail number PK-LHM has used the latter value.
For "Posisi Baca", selecting EoF will read the FDR file starting from the end of file. Otherwise, selecting BoF will read the FDR file starting from the beginning of the file. For "Panjang Bacaan", set the value of "Jam" for hour and "Menit" for minute. Typical single flight would be an hour -or 60 minutes. Here, we are now ready to create intermediate file. Click "Open Raw".
Step two. From the interm_file.mat which contains ARINC 717-structured data, the program need to build -a so called result file, which also is a mat file that is already contain parameters value in engineering unit (for example, Pressure Altitude in Feet, IAS in Knot, Autopilot status in ON/OFF, and so on). On the main window, click "Build Result".
We are now asked for intermediate file that we had previously created. Open it. Then, a second window is asking us to select a dataframe layout file in mat extension.
Program will now converting the specified raw data into a more usefull information by using specified dataframe layout.
Now, result file had been created. To show result, click "Plot Result".
Go to Option -> Load and select the recently created result file. And there you go, program will try to show all active parameters. Change pop-up menu to show other parameters.
If you want to print these four subplot together, go to Option -> Print. It will be saved to where aPENGAMAT executable file is located.
Now, as my promise, I will give you the files. Here is for dataframe layout access database and here is for the aPENGAMAT executable file. Should you have discussion, please contact me.
Update Log:
23 August 2011,
- Redesigned: result file restructured to adapt event finder logic. You can also use this file to show flight parameter into Baca Window.
- Access database restructured.
- Added: zoom capabilities.
- Added: Find Events button. Note: Still struggling coding for the logic ;)
- Solved: Cannot collect parameter with more than 1Hz sampling rate
- Note: I am currently working to add event exceedance detection feature between my idle work hours. Be patient ;)
- Plot Result Figures (Baca Window) can now be zoomed simultaneously.
- Intermediate process now runs twice faster!
- Teledyne and Hamilton synchronizatation type now available.
- 64 and 128 wps file can now be read.
