Abstract:
A flight recording system with a simple, precise, reliable and low cost installation and connection architecture. This system includes a box provided with reversible fastening means onto the aircraft, said box comprising recording means for recording conversations and audio communications and audio management means for managing signals and for providing the recording means with signals originating from the audio environment of the cockpit.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of the French patent application No. 1350342 filed on Jan. 15, 2013, the entire disclosures of which are incorporated herein by way of reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    This invention relates to the domain of flight recording in an aircraft and more particularly recording of conversations and audio communications in the cockpit. 
         [0003]    The development and installation of the flight recording system is important for investigations in the case of an incident or accident, thus contributing to increasing the efficiency and to promoting safety in aviation. 
         [0004]    An aircraft is usually equipped with two recorders. The first is a conversations and messages recorder designed to record conversations and communications in the cockpit and data-link messages transmitted between the ground and the aircraft. The second is designed to record flight parameters. The two recorders are synchronized with a common time base. By regulation, the two recorders are installed in the aft part of the aircraft close to the tail because this is the part that is usually best protected after an impact with the ground or the sea. 
         [0005]      FIG. 3  diagrammatically shows an example of a conversations and messages recording system according to prior art. 
         [0006]    This system  101  comprises a flight recorder  107 , an Audio Management Unit (AMU)  109 , a Cockpit Voice Recorder Control Unit (CVRCU)  110 , a Cockpit Area Mike (CAM)  112 , and a Data-Link System  114 . 
         [0007]    The flight recorder or “black box”  107  comprises a Cockpit Voice Recorder (CVR)  107   a  designed to record conversations and communications in the cockpit and a data message recorder  107   b  designed to record flight data messages transmitted between the ground and the aircraft. 
         [0008]    The data-link system  114  is installed in the avionics rack and supplies data messages to the message recorder  107   b.    
         [0009]    The CAM cockpit area mike  112  is installed in the cockpit to pick up conversations and cockpit area noise. It is connected to the cockpit voice recorder CVR  107   a  through the cockpit voice recorder control unit CVRCU  110 . This CVR is installed in the cockpit and comprises a preamplifier  116  to amplify the signal output from the cockpit area mike CAM  112 . 
         [0010]    The audio management unit AMU  109  is installed in the avionics rack and it is destined to cover all radio and interphone communications between crew members and to send audio signals output from communications and the cockpit audio environment to the cockpit voice recorder CVR  107   a.    
         [0011]      FIG. 4  diagrammatically shows the functional architecture of a flight recorder according to prior art. 
         [0012]    The flight recorder  107  comprises two subassemblies. The first subassembly consists of a Crash Survival Module Unit (CSMU)  111  inside which all recorded data are stored. More particularly, the crash survival module unit CSMU  111  is composed of several layers enclosing a memory  113  of the solid state type. The CSMU unit  113  is also provided with an Underwater Locator Beacon (ULB)  115  that is switched on in the case of immersion and emits an ultrasound signal to assist in positioning the aircraft. 
         [0013]    The second subassembly consists of an electronic interface  116  that manages all received signals. It comprises four input-output interfaces  118   a - 118   d , a Field Programmable Gate Array (FPGA)  120   a,  an Audio Digital Signal Processing (ADSP) means  122 , an interface  124  for the CSMU unit and an interface  125   a  for the electrical power supply. 
         [0014]    The first interface  118   a  is an input interface that receives analog audio signals on four distinct channels (channel 1-channel 4). The first, second and third channels are connected to audio communication equipment (boomsets, microphones, interphones, etc.) in the cockpit through the audio management unit AMU  109 . More particularly, the first, second and third channels are connected to communication equipment of the pilot, co-pilot and the third occupant respectively. The fourth channel is connected to the cockpit area mike CAM  112  through the CVRCU  110 . The first interface  118   a  converts analog signals received through the four channels into digital signals before sending them to the signal processing unit ADSP  122 . 
         [0015]    The second interface  118   b  is an output interface connected to an audio monitor of the conversation voice recorder control unit CVRCU  110 . Thus, an audio signal representative of correct operation of the flight recorder may be sent to the CVRCU unit  110 . 
         [0016]    The third interface  118   c  is an input-output interface connected to the conversation voice recorder control unit CVRCU  110  and the cockpit area mike CAM  112 . 
         [0017]    The fourth interface  118   d  is an input-output interface compatible with the ARINC  429  standard and it comprises a time reference input (GMT Input), and an input (CMS Input) and an output (CMS Output) for management of failures connected to a centralized maintenance system (CMS) on the aircraft. 
         [0018]    The field programmable gate array FPGA  120   a  sets up links with activation logic to automatically start up the recorder as soon as an engine is powered. 
         [0019]    The audio signal processing means ADSP  122  manages all audio data and transfers them in digital format to the interface  124  of the CSMU unit. This unit compresses data before saving them in the solid-state memory  113  of the CSMU  111 . 
         [0020]    The electrical power supply interface  125   a  provides appropriate voltages to the different components of the flight recorder  116 . 
         [0021]      FIG. 5  diagrammatically shows the functional architecture of an audio management unit according to prior art. 
         [0022]    The audio management unit AMU  109  comprises an adaptation board  132 , a dual audio board  134   a,    134   b,  an electrical power supply interface  125   b  and a field programmable gate array FPGA  120   b.    
         [0023]    The adaptation board  132  comprises audio input and output interfaces to interface with all analog audio signals for the pilot, co-pilot and the third occupant. 
         [0024]    The adaptation board also comprises an interface  132   a  compatible with the ARINC  429  standard for failure management inputs (CMS Input) and outputs (CMS Output). 
         [0025]    Furthermore, the adaptation board  132  comprises an interface  132   b  with the flight recorder comprising a time reference input (GMT Input) and three outputs through which audio signals are transmitted on three different channels specific to the pilot, the co-pilot and the third occupant. This interface  132   b  is adapted to mix the audio signals corresponding to each channel before sending them to the recorder  107 . 
         [0026]    The dual audio board  134   a,    134   b  comprises first and second dedicated boards for conversations and audio communications of the pilot and the co-pilot respectively. The dual audio board  134   a,    134   b  is destined to process digital audio data. It is also destined to manage radio communication and navigation functions and to handle management of failures and the SELCAL selective call between the ground and the aircraft. 
         [0027]    Finally, the electrical power supply interface  125   b  is destined to supply appropriate voltages to the different components of the audio management unit  109 . 
         [0028]    The audio management unit  109  and the flight recorder  107  thus comprise heterogeneous interfaces (analog and digital) that require adaptation and conversion means and a large number and variety of connections. 
         [0029]    Furthermore, as mentioned above, the audio management unit is located in the avionics rack while the flight recorder is installed in the aft part of the aircraft to satisfy the regulations. This requires many long wire connections, which increases the aircraft mass balance. 
         [0030]    Furthermore, the architecture of the connections between the two equipment units is fairly complex and cables connecting the audio management unit to the flight recorder and carrying the different analog and digital signals must pass through the entire aircraft, passing through zones and routes sensitive to interference, which creates a number of installation problems due to segregation constraints. 
         [0031]    Furthermore, aeronautic needs are increasingly dictated by particularly severe reliability and redundancy constraints. Thus, the intended regulations require that two flight recorders should be installed in different parts of the aircraft, consequently once again increasing the number of wire connections. 
         [0032]    Consequently, the purpose of this invention is to overcome the disadvantages mentioned above by disclosing a recording system with a simple, precise, reliable and low cost installation and connection architecture. 
       SUMMARY OF THE INVENTION 
       [0033]    This invention relates to a flight recording system in an aircraft comprising recording means to record conversations and audio communications, and audio management means destined to provide the recording means with signals output from the audio environment in the cockpit, the system comprising a box containing said recording means and said management means. 
         [0034]    This reduces the weight and simplifies the connection architecture by reducing wiring while minimizing interference, given that the recording means and management means are contained in the same box. 
         [0035]    Advantageously, said recording means and said management means are combined together in said box and their common functions are factorized. This can simplify and minimize the number of components and connections, facilitate integration and reduce the weight and costs. 
         [0036]    The invention also relates to an aircraft comprising a first box with the above characteristics installed in the avionics rack and a second box with the above characteristics installed in the aft part of the aircraft. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0037]    Other characteristics and advantages of the invention will become clear after reading the preferred embodiments of the invention with reference to the appended figures among which: 
           [0038]      FIG. 1  very diagrammatically shows a flight recording system according to one embodiment of the invention; 
           [0039]      FIG. 2  very diagrammatically shows the functional architecture of the management and recording box according to a preferred embodiment of the invention; 
           [0040]      FIG. 3  diagrammatically shows an example of a recording system according to prior art; 
           [0041]      FIG. 4  diagrammatically shows the functional architecture of a flight recorder according to prior art, and 
           [0042]      FIG. 5  diagrammatically shows the functional architecture of an audio management unit according to prior art. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0043]    The concept of the invention comprises of integrating the audio management function into the electronic interface of the flight recorder. 
         [0044]      FIG. 1  very diagrammatically shows a flight recording system according to one embodiment of the invention. 
         [0045]    According to the invention, the recording system is composed of a management and recording box  3  comprising recording means  7  and audio management means  9 . Thus, the recording means  7  and management means  9  are integrated into the same box  3 . 
         [0046]    The recording means  7  is destined to record conversations, noise and audio communications in the cockpit. The audio management means  9  is destined to manage signals and provide the recording means  7  with signals output from the audio environment in the cockpit. 
         [0047]    More particularly, the recording means  7  and the audio management means  9  are merged together by factorizing (i.e., put in common) their common functions (cross-hatched part) to form a single unit materialized by the management and recording box  3 . Thus, same electronic means may be used for audio management and recording functions. Advantageously, all audio signals received or sent by the box  7  pass through digital connections. 
         [0048]    Furthermore, the embodiment in  FIG. 1  shows that the management and recording box  3  is provided with reversible attachment means  5  on the aircraft. 
         [0049]      FIG. 2  diagrammatically shows the functional architecture of the management and recording box, according to a preferred embodiment of the invention. 
         [0050]    The box  3  comprises two parts. The first part still consists of a CSMU unit  11  enclosing storage (or memory) means  13 , for example a solid state type memory, for storing recorded data. Thus the memory  13  is protected by a casing resistant to shocks, fire and deep immersion. The CSMU unit  11  is also provided with a ULB beacon  15 . 
         [0051]    The second part of the box corresponds to the electronic interface  16  that controls and manages the signals and records the different data in the memory  13 . This second part comprises first and second end systems  17   a,    17   b,  first and second digital sound links  19   a,    19   b,  first and second digital signal processing means  21   a ,  21   b,  a calculation means  23  and electrical power supply means  25 . 
         [0052]    The first and second end systems  17   a,    17   b  are adapted to be connected to first and second communication networks respectively (AFDX network 1, AFDX network 2) of the aircraft. 
         [0053]    It will be noted that the aircraft communication system allows digital equipment to send and/or receive data through AFDX (Avionics Full Duplex Switched Ethernet) type networks. 
         [0054]    It is reminded that the AFDX network developed for aeronautical needs is based on a switched Ethernet network. Furthermore, the AFDX network uses the concept of a virtual link defined as a path oriented through the network, derived from a source terminal and serving one addressee or a plurality of addressees. 
         [0055]    The box  3  can then simultaneously send and receive frames through an end system  17   a,    17   b,  on virtual links on the same physical link. The AFDX network is also deterministic in the sense that virtual links have guaranteed characteristics in terms of latency limit, physical flow segregation, passband and flow. Each virtual link has a reserved path from end to end through the network for this purpose. Data are sent in the form of IP packets encapsulated in Ethernet frames. 
         [0056]    All radio communication and navigation signals and selective calls SELCAL between the ground and the aircraft are thus managed in complete safety through AFDX networks through the first and second end systems  17   a,    17   b . Similarly, signals related to the time reference, failure management and activation logic pass through the first and second end systems  17   a,    17   b.    
         [0057]    The first and second end systems  17   a,    17   b  thus replace several interfaces of the audio management unit and the flight recorder according to prior art such as ARINC 429 interfaces and field programmable gate arrays FPGA (see  FIGS. 4 and 5  in prior art). 
         [0058]    The first and second digital sound links  19   a,    19   b  are for example digital audio serial links. Each of the digital sound links  19   a,    19   b  is adapted to be connected to a set of audio channels  27   a - 27   d  comprising a first channel  27   a  for the pilot, a second channel  27   b  for the co-pilot, a third channel  27   c  for the third occupant of the cockpit, and a fourth channel  27   d  for the audio environment (engine noise, alarms, actuation of commands, etc.) in the cockpit. According to the invention, boomsets, mikes, interphones, area mike and other sound units in the cockpit are digital units. Thus, there are no longer any analog connections or interfaces, which reduces the number of connections and further simplifies the architecture in comparison with the prior art. It will be noted that the cockpit area mike CAM is now directly connected through the fourth channel  27   d  to the management and recording box  3 . 
         [0059]    The first and second digital signal processing means  21   a,    21   b  are connected to the first and second end systems  17   a,    17   b  respectively, and to the first and second links  19   a,    19   b.  All data and all signals passing through the end systems  17   a,    17   b  and the digital sound links  19   a,    19   b  are managed and processed by the processing means  21   a,    21   b  according to their assignment. Thus, without using any analog/digital conversion, the processing means  21   a,    21   b  perform management unit processing functions ( FIG. 4  in prior art) as well as flight recorder functions ( FIG. 3  in prior art). 
         [0060]    The digital signal processing means  21   a,    21   b  are configured to manage all radio communication and radio navigation functions through AFDX networks via the end systems  17   a,    17   b.  This helps to manage communications between crew members, between the cockpit and the cabin, between the cockpit and the ground, and passenger announcements, etc. Failure management and the activation logic are also managed by the digital signal processing means  21   a,    21   b  through the AFDX networks. 
         [0061]    Similarly, the digital signal processing means  21   a,    21   b  are configured to manage and mix audio signals belonging to a single channel before sending them to the calculation means  23 . 
         [0062]    Advantageously, the first processing means  21  a are dedicated to pilot conversations and communications, while the second processing means  21   b  are dedicated to co-pilot conversations and communications. Thus, the duality of the processing means  21   a,    21   b  and the digital sound links  19   a,    19   b  maintains segregation between the pilot&#39;s channel and the co-pilot&#39;s channel. 
         [0063]    The calculation means  23  provides the interface between the memory  13  and the first and second processing means  21   a,    21   b.  The calculation means  23  performs the same functions as the interface of the CSMU unit according to prior art (see  FIG. 4 ) and in particular, data compression for data to be recorded before the data are sent to be recorded in the memory  13 . 
         [0064]    The first and second processing means  21   a,    21   b  and the calculation means  23  are also adapted to manage and record data messages received from the first and second AFDX networks through the first and second end systems  17   a,    17   b,  in the memory  13 . Thus, voice data and data messages are recorded in the same box  3 . 
         [0065]    Finally, the electrical power supply means  25  will provide appropriate voltages to the different means or components of the box  3 . The electrical power supply means  25  are thus common to audio management and recording functions. 
         [0066]    It will be noted that the second part of the box  3  (i.e., the electronic interface  16 ) performs all audio management functions and then corresponds to the audio management means  9 . Furthermore, both of the two parts correspond to the recording means  7 . In other words, with this preferred embodiment of the invention, the audio management means  9  are entirely included in the recording means  7 . 
         [0067]    Thus, audio management and recording functions according to the invention are made entirely digitally inside a single box  3 . This eliminates tens of meters of wiring, minimizes interference problems, simplifies the connection architecture and eliminates equipment weighing several kilograms. 
         [0068]    In particular, all audio communication and recording signals are digital and are entirely managed through the end systems  17   a,    17   b  and digital sound links  19   a,    19   b.  Thus, all adaptation interfaces and all analog-digital or digital-analog conversions according to the prior art are eliminated. 
         [0069]    Furthermore, all signals and data messages are managed through AFDX networks. Thus, ARINC 429 interfaces and logical interfaces are no longer necessary. 
         [0070]    Advantageously, according to a first embodiment and installation method, the box  3  is compatible with the ARINC 600 standard so that it can thus be directly installed in the avionics rack. 
         [0071]    According to a second embodiment and installation method, the box  3  is compatible with the ARINC 404 standard, for example with the ½ ATR long format. This means that the box can be installed close to the avionics rack. 
         [0072]    Advantageously, a first management and recording box  3  is installed close or inside the avionics rack and a second management and recording box  3  is installed in the aft part of the aircraft. 
         [0073]    As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of my contribution to the art.