Retrieving a V3 .DAT File

Retrieving a V3.DAT is done by using the DJI Assistant 2 app supplied by DJI. A V3 .DAT will exist on any DJI drone that comes after Phantom 3 or Inspire 1. This includes the Mavic Pro, Phantom 4, Phantom4 Pro, Inspire 2, Inspire 2 Pro, Matrice 100, Matrice 200, Matrice 600, and Spark.

There are two methods used by the Assistant to retrieve the .DAT. Depending on the AC firmware and the DJI Assistant 2 version one or both of these methods will be available to you. You will need to determine which method exists for your particular AC firmware. Those methods can be found here DJI Assistant creates a compressed file containing the .DAT and here.

Assistant creates a compressed file containing the FLYXXX.DAT(s)

With this method a file is created that has a name something like DJI_ASSISTANT_EXPORT_FILE[2016-10-27 22-40-28].DAT. In turn, this file will contain one or more FLYXXX.DAT files in a compressed format. Both CsvView and DatCon can accept this file because they know how to decompress and extract the contained FLYXXX.DAT file(s). You can also use the supplied app ExtractDJI to manually extract the FLYXXX.DAT(s).

  1. Use the supplied USB to connect the aircraft to your computer. Make sure the battery has at least 50%.
  2. Start DJI Assistant 2 and wait for it to display the AC as a Connected Device.
    Select the logo.
  3. At this point it what you see next depends on the AC firmware and/or the Assistant version. Earlier Assistant versions offered a Flight Record tab.

    Later versions now use the Data Upload tab.

    Next you'll be asked to confirm that it's OK to enter Flight Data Mode. Select OK.
  4. If the correct tab is selected a list of flights will be shown.

    Select just the Flight Control File of the flight you want. Don't select the Vision Module File. Click the Save To Local button which will ask you for a directory to write the extracted .DAT file.
  5. Ultimately a file with a name something like DJI_ASSISTANT_EXPORT_FILE[2016-10-27 22-40-28].DAT will be created.

Assistant displays the FLYXXX.DAT files directly

With this method the Assistant will mount a drive on your computer that contains the FLYXXX.DAT files.

  1. Use the supplied USB to connect the Mavic or P4 to your computer. Make sure the battery has at least 50%.
  2. Start DJI Assistant 2 and wait for it to display the AC as a Connected Device.
    Select the logo.
  3. On the next screen select the Flight Data tab.

    Next you'll be asked to confirm that it's OK to enter the Flight Record page. Select Confirm.
  4. Next the internal SD card containing the flights will appear as disk on your PC or Mac. Use the OS's file manager to open this disk and you should see the list of available .DAT files.

Picking the correct .DAT

The FC File starts recording when the battery is turned on and ends recording when the battery is turned off or removed. The FC File will also stop recording when the AC is put into Flight Data Mode by DJI Assistant 2. Thus, an "extra" FC File is created when you are attempting to retrieve the FC File you want.

Each FC File has a DateTime and usually this can be used to determine the desired FC File. However, the DateTime comes from the RC. If the battery is turned on while the RC is not powered up the DateTime is set to the DateTime of the last FC File. The result is two FC Files with the same DateTime. Also, if the FC File reaches a size around 460 MBytes the AC will end that FC File and start a new FC File. This new FC File will have the same DateTime as the first FC File.

The size of the FC File can be used to estimate the length of the time the battery was on. The ratio is .11 MBytes/second. Be aware that the battery will be on longer than the length of the flight.