This invention relates to Light Weight Cockpit Voice & Flight Data Recorder (CVFDR) for
use in Aircraft & Helicopters and, more particularly, to ready to use digital data recorder system
on aircraft digital data bus.
BACKGROUND OF THE INVENTION
Flight data recorders are monitoring and recording instruments, carried aboard an
aircraft, which systematically monitor and store the instantaneous values of various aircraft
parameters. Early recorders were analog electromechanical devices which periodically marked,
in analog form, the value of a given airplane parameter on a moving wire or other permanent
storage medium. The time of occurrence of the parameter was also suitably scribed into the
medium opposite the mark for the sensed parameter. Subsequently, digital flight data recorders
have been developed which operate by converting each analog aircraft parameter into a
corresponding digital signal, and storing the digital signals on a permanent storage medium
such as magnetic tape. The numerous mechanical parts employed in the analog and digital type
electromechanical flight data recorders have rendered such units expensive to construct and
bulky in design, requiring periodic maintenance of the mechanical parts. In addition, extraction
of the stored data from these data recorders requires physical removal of the storage medium.
The development of solid state memory devices, such as electrically erasable read-only
memory, has led to the design of all solid state flight data recorders. The solid state flight data
recorders commonly employ a Data Acquisition System (DAS) which receives and processes
the various aircraft input signals to be monitored and stored under the control of a central
processing unit (CPU). The analog signals are converted to digital signals by the DAS and,
under CPU control, are passed over a data bus to the solid state memory devices.
Programming within the CPU controls the processing of input airplane signals to corresponding
digital signals through the DAS and the subsequent transference of these digital signals to
controlled locations in the solid state memory. Further advancement in the aircraft system led to
the use of pre defined protocols for communication between various sub systems of the aircraft.
SUMMARY OF PRESENT INVENTION
The present invention therefore is directed to Light Weight Cockpit Voice & Flight Data
Recorders. With the advancement in the field of avionics the system started communicating with
other systems on digital data buses such as MIL-STD-1553, ARINC-717 & ARINC-429
predominantly.
This led to reduction in processing time since the acquisition was being performed by
one system and relevant information was shared with other sub systems of the aircraft and
Annexure‐II
individual systems were relieved from the extra burden of processing of data at individual
systems. This resulted in tremendous weight reduction of the data recorders & resulted in
removal of acquisition system from the Flight Data Recorders.
The present invention is directed for use in a Rotary Wing Aircraft. An aspect of the
present invention is the ability of the system to handle power interruption of few milliseconds &
also sustain uninterrupted operation during engine start when voltage drops during engine start.
A further aspect of the invention is the universal application of the present data recorder
system in all rotary wing aircraft where the data is being converted on digital data bus & sent on
ARINC-717 & ARINC-429 interface.
An another aspect of the invention is its unique mechanical design with light weight
metallic plates which forms the complete structure with only 02 plates. An another aspect of the
invention is its capability to acquire & digitize voice data from pilot, co-pilot, area mic & also
provides spare audio channel for use on aircraft.
Light Weight Cockpit Voice & Flight Data Recorder (CVFDR) carries out the following
functions:
• Acquires digital data on ARINC-717 & ARINC-429 interface
• Acquires voice data from selected channels
• Handles Power interruption of aircraft power supply
• Stores data & voice in crash protected memory
Features of light weight CVFDR:
• Unique mechanical Design to reduce weight
• Removal of acquisition system by acquiring data on digital data interface to reduce
weight
• Use of miniaturized CPLD/FPGA’s to achieve desired functionalities.
BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the present invention will become more apparent and
descriptive in the description when considered together with figures/flow charts presented:
Figure 1 is a Block Diagram of Cockpit Voice & Flight Data Recorder (CVFDR)
Figure 2 is a Block Diagram of Processing of ARINC-717 signals in CVFDR
Figure 3 is a pictorial view of mechanical structure of CVFDR
Figure 4 is a Block Diagram of Processing of ARINC-429 signals in CVFDR
Figure 5 is a Block Diagram of Processing of Audio signals in CVFDR
Annexure‐II
DETAILED DESCRIPTION
The light weight Cockpit Voice & Flight Data Recorder (CVFDR) is capable of recording
various aircraft parameters which are coming from aircraft via digital data interface on
ARINC717 interface in variable word format along with critical parameters on ARINC 429
interface from aircraft stand by instrument System as well as four channel audio data during
flight.
This acquires data from cockpit voice through ARINC 717. It contains crash protected
memory module (CPMM). The acquired data is stored in to the crash protected memory module
(CPMM). This data will be utilized later for crash analysis. The DRU will also have ULB (Under
water Locator Beacon) an independently operated unit with battery. This is mechanically fitted
with DRU such that it does not get separated from DRU in the event of crash. The ULB unit
does not have any electrical interface with DRU. Battery in ULB needs to be changed
periodically as per the ULB manufacturer instruction.
The Data Recording Unit (DRU) acquires flight data from the aircraft over ARINC 717
Harvard Bi-phase standard and stores in CPMM. DRU also acquires the a/c Audio directly and
record in CPMM. The Processor Card is the core of the DRU. It acquires flight data via
ARINC717 or ARINC429 interface and voice data from Audio I/O Card in the DRU. The Audio
I/O card will be interfaced with the processor’s data, address and control bus, which are brought
out on the PCB edge connector.
The CVFDR carries out the following functions:
• Built in test
• Acquisition of Arinc-717 & Arinc-429 data
• Acquisition of Voice data
• Handles Power interruption on aircraft power supply
• Provides power back up to self in event of power loss from aircraft
The built in tests are performed to check the serviceability of Cockpit Voice & Flight Data
Recorder. Functioning of the CVFDR can be divided into following blocks:
ARINC-717 Interface
ARINC-717 interface standard is used to record flight data. The transmitter sends
continuous data stream of Harvard Bi-phase encoded 12-bit words in frames. The CVFDR
provides the ARINC-717 interface through microprocessor, CPLD and the differential driver. The
Annexure‐II
CPLD generates the Harvard Bi-phase output. This output from the CPLD is applied as an input
to the Differential Driver.
ARINC-429 Interface
ARINC-429 interface standard is used to record flight data. The transmitter sends 32bit
word data to the CVFDR which includes the details of the parameter, label, value etc. The data
is passed through transceivers, buffers to ARINC 429 controller which gives the requisite
information to the processor. ARINC 429 is selected from controller. A clock has been routed to
the ARINC 429 transceiver. Variable clock rates can be selected & Data buffer is controlled by
CPLD and controller signals. The interrupt from the ARINC429 controller is indicated to the
controller.
Audio IO Interface
AUDIO interface is done with help of CODEC. The received audio signal from isolator is
first selected through Analog Switch and then it is passed to the CODEC through passive filter
and amplifier. The audio signals are the differential signals. The CODEC is interfaced with DSP
Processor. The input audio signal should be isolated and then send to the Analog switch. The
CODEC is controlled through SPI bus and ADC & DAC data’s transfer takes place through
SPORT bus.

WE CLIAMS:-
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. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A Light Weight Cockpit Voice & Flight Data Recorder (CVFDR) system comprising a computer system for acquiring digital data from Arinc-717, Arinc-429 data bus & also acquires voice data on selected channels to being arranged to record the duration for the purpose of defect investigation & analysis.

2. CVFDR System as claimed in claim 1, wherein the light weight means the unique mechanical design having two plates in overall enclosure.

3. A CVFDR system as claimed in Claim 1, wherein the system includes means for downloading information recorded in the solid state memory interfaced with computer system relating to the aircraft health on board processing or subsequent analysis.

4. An aircraft recording system as claimed in Claim 3, wherein the computer system has output means for writing data accumulated in the computer system for the storing means in the course of use of the aircraft to a recording medium for on board processing or use and analysis by a separate ground based computer system to enable the aircraft defect/crash investigation and analysis.

5. The CVFDR of claim 1, wherein said processing means comprises: Signal conditioning circuit & digitization of signals from voice & digital data on Harvard bi-phase interface.

6. A recording system as claimed in any of the preceding claims wherein a crash protected recorder is provided which is coupled to the computer system to receive selected flight data and health information there from.

7. A recording system as claimed in any of the preceding claims, wherein a cockpit voice recorder is included in the system.

8. A recording system as claimed in any of the preceding claims, handles Power interruption on aircraft power supply

9. A recording system as claimed in any of the preceding claims, provides power back up to self in event of power loss from aircraft

10. A recording system as claimed in any of the preceding claims, provides visual warning at the aircraft cockpit on indicator when hardware fails during operation of CVFDR system ,TagSPECI:As per Annexure-II