FIELD OF THE INVENTION
The present invention relates to packing of acquired aircraft data for storing in
the protected memory module. The invention provides the capability to pack
the data in the format such that when downloaded, the data acquired and
recorded can be validated for its integrity and data for every second can be
differentiated. This helps in more detailed analysis of aircraft parameters.
BACKGROUND OF THE INVENTION
The SOLID STATE FLIGHT DATA RECORDER (SSFDR) is an electronic system
that is used to record 25 hours of Aircraft data during flight. This avionics
system has a crash protected memory module where all the flight data is
stored. Main application software resides and run on this board. This board will
also contain RS‐232, RS‐422 serial communication.
Flight data recorder records aircraft data of various parameters and audio data
through various channels. Aircraft data being so critical make the acquisition
and storage of data important. Criticality of the system makes the data
integrity an important aspect. The generation of internal parameters and their
formatting with aircraft data provides for this capability.
Summary of present invention
In accordance with one aspect of present invention, is to provide for the
generation of headers and identifiers for transmission of data.
In accordance with second aspect of the present invention, is to provide for
packing of data in specific frame format such that the validity and integrity of
data can be maintained.
In accordance with another aspect of the present invention, is to provide for
detailed and accurate analysis of aircraft data by the data analysis equipment.
Annexure‐II
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention will become more apparent and descriptive
when considered together with figures.
Figure 1 describes the way in which internal parameters are generated and
formatted with aircraft data and stored.
Figure 2 describes format in which aircraft data is stored in Protected memory
module and how the internal parameters are stuffed with aircraft parameters.
Figure 3 describes the various interfaces in the Flight data recorder.
DETAILED DESCRIPTION
Following internal parameters are generated by the firmware run in the Flight
data recorder unit:
1) Frame Sync A
2) Frame Sync B
3) Elapsed Time (two words)
4) SRT (Sortie Count or flight no.)
5) Error Word (Four)
The synchronization words occupying words 1(FSA) and 129 (FSB) in the frame
format described in figure 2. FSB is chosen to be the 1’s complement of word
FSA and the pattern of both words allows the ‘Barker Code” principle to be
applied to seek and maintain synchronization with the data stream on read
back of data.
These have the following patterns:
 FSA 0110 0000 0110 (606)
 FSB 1001 1111 1001 (9F9).
Sortie count : The SSFDR stores Sortie Count (Flight no.) in a non‐volatile
memory (NV RAM) and PMM simultaneously. Sortie Count increments
whenever +27V DC power supply of SSFDR is SWITCHED ON and recording
condition is met. One word of 12 bits is allocated for Sortie Count and
Annexure‐II
Maximum No. of Sortie can be 4096. The Sortie count is reset to 1 after the
maximum sortie count has been achieved.
Elapsed Time: (TIM) is internally generated and incremented & recorded every
second. Two 12 bit words (TIM1 as LSB) & (TIM2 as MSB) is used to store the
elapsed time in SSFDR.
• Elapsed time remains zero until condition for Start of Recording is met.
• Elapsed time resets to one whenever SSFDR power is SWITCHED ON.
Error Words:
There are 4 BITE words, 2 per frame,
 Error word 1 (BT1)
 Error word 2 (BT2)
 Error word 3 (BT3)
 Error word 4 (BT4)
Even Frame have Error Word 1 (BT1) and Error Word 3 (BT3) at location 78 &
190 respectively and Odd frame have Error Word 2 (BT2) and Error Word 4
(BT4) at location 78 & 190 respectively in the frame format.
The error words gives the status of all the hardware components during each
second of flight.
Figure 1 describes the flow in which the internal parameters are generated and
are stored with all the other aircraft parameters :
1) Power On the SSFDR.
2) Perform the power on built in test (PBIT) and the status of all the
individual hardware components is packed in error words.
3) Initialize all the components and increment the sortie number if SSFDR is
in record mode.
4) SSFDR is in the record mode and when the recording condition is met
,the elapsed time starts incrementing continuously by 1 every second.
Annexure‐II
5) All the parameters are recorded and packed with the internal
parameters FSA, FSB,SRT,TIM and error words in the format as shown in
figure 2.
6) The packed data is stored in Protected memory module every second.
7) Power off the SSFDR.

WE CLAIMS:-
Accordingly, the description of the present invention is to be considered as illustrative only and is for the purpose of teaching those skilled in the art of the best mode of carrying out the invention. The details may be varied substantially without departing from the spirit of the invention, and exclusive use of all modifications which are within the scope of the appended claims is reserved.

We Claim that:

1. Generation and recording of internal parameters is significant keeping in mind criticality of aircraft data .
2. Algorithm of claim 1 is implemented for system with frame format as shown in figure 2.
3. Algorithm of claim 1 is implemented for flight data recorder built around microcontroller.
4. Algorithm of claim 1 is to provide for packing of data in specific frame format such that the validity and integrity of data can be maintained.
5. Algorithm of claim 1 is to provide for detailed and accurate analysis of aircraft data by the data analysis eq ,TagSPECI:As per Annexure-II