What is Flight Data Decoding?
“FDM data decoding” refers to the process of extracting meaningful information from the raw flight data obtained from the Flight Data Recorder (FDR) or Quick Access Recorder (QAR). The flight data recorded by these devices is typically in a binary format, which needs to be decoded to retrieve the actual values of different parameters recorded during the flight. Decoding involves interpreting the binary data and converting it into a human-readable format, such as numerical values, text, or graphical representations. Flight data is usually encoded in a continuous datastream organized in 12bits per word. Data capacity ranges from 64 up to 2048 words per second.
The decoding process typically includes the following steps:
1. Data Format Identification
The decoding process begins by identifying the data format used by the FDR or QAR. Each manufacturer may have its own specific data format, which may vary based on the aircraft model and software version.
2. Data Structure Parsing
Once the data format is identified, the binary data is parsed according to the predefined data structure. The data structure provides information about the arrangement of different parameters within the binary stream, their data types, and their offsets or locations within the data.
3. Parameter Extraction
Based on the parsed data structure, specific parameters of interest are extracted from the binary stream. These parameters may include altitude, airspeed, vertical acceleration, engine parameters, control inputs, and other relevant flight data.
4. Conversion and Scaling
The extracted parameters may be in raw binary form or encoded in a specific representation. They need to be converted into appropriate units and scaled to their real-world values. For example, a binary value representing altitude may need to be converted into feet or meters, and a binary value representing temperature may need to be converted into Celsius or Fahrenheit.
5. Quality Checks
During the decoding process, data quality checks are performed to ensure the integrity and accuracy of the decoded values. This may involve verifying the data against predefined ranges, performing consistency checks between related parameters, and identifying any missing or inconsistent data.
Decoding involves interpreting the binary data and converting it into a human-readable format, such as numerical values, text, or graphical representations.
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