Abstract:
An emergency flight safety device for flight crew members ( 3 ) of an aircraft in an emergency situation. The device includes a full-face mask ( 1 ) and a display ( 31 ) that is integrated into the full face mask ( 1 ). The display shows flight data and ensures that the crew ( 3 ) has access to essential information even in the case when smoke otherwise largely blurs the view in the aircraft cabin. The emergency flight safety device also includes an oxygen and air supply apparatus ( 14-18 ) for supplying oxygen and air to the interior of the mask ( 1 ). The oxygen and air supply apparatus ( 14-18 ) includes a purification device to purify polluted cabin air in order to prevent the crew members ( 3 ) from being intoxicated by poisonous smoke.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an emergency flight safety device for a person in the cockpit of an aircraft, the device including a full-face mask and an integrated display with at least one display area for displaying flight data. 
     BACKGROUND OF THE INVENTION 
     Recent incidents in civil and military aviation that were initialized by fire, fume or smoke resulting from malfunctioning electrical appliances or wiring, have caused tremendous loss of human life and substantial financial damage. In an emergency situation it is vital that the pilot of an aircraft have a clear view of the critical flight information data, full control over the orientation of the aircraft in the three-dimensional space, and proper breathing conditions in case of loss of cabin pressure or health-critical fume. In addition, the safety of an emergency landing is substantially enhanced when the pilot has an undisturbed view of the final touchdown spot. 
     Information displaying methods according to the state of the art, however, fail to provide the pilot with the critical flight information data in certain emergency situations, especially in situations where smoke has developed. State of the art is either described as dedicated breathing equipment against nuclear, biological or chemical contamination (NBC protection equipment), as e.g. disclosed in U.S. Pat. No. 4,741,332, or as improvement of a helmet mounted display by means of a specific cathode ray tube installation, as e.g. disclosed in EP-A-0 301 997. The European Patent Application publication 0 252 281 and the U.S. Pat. No. 5,601,078 disclose a not specifically determined breathing apparatus that can be used underground or in non-airborne embodiments. Attached to the breathing mask, on the outside, a removable, mask mounted monocular display is disclosed, capable of displaying measured data of low complexity with the help of a dedicated illumination system. 
     All these information-displaying methods have in common that they do not allow a pilot to fly an aircraft in emergency situations involving heavy smoke. 
     Existing emergency devices for airplanes have concentrated on providing the cockpit crew members with smoke goggles and an oxygen mask in case of loss of cabin pressure (see, e.g., D. Wilkins “Helmet Mounted Displays in Transport Emergency Conditions”. SPIE Conference on Helmet- and Head-Mounted Displays IV, SPIE Vol. 3689, 206-209, 1999). Alternatively, full-face masks have been used to protect the pilot&#39;s eyes from smoke (R. Stünkel “All you need is oxygen” Fliegermagazin 9/99, 32-35, September 1999) or the combination of a breathing mask with a protective hood that can enclose the pilot&#39;s head (U.S. Pat. No. 5,115,804) have been proposed. The disadvantage of all these approaches is the reduced visibility under heavy smoke conditions. Smoke drastically reduces the readability of instruments located in the instrument flight panel. As a possible solution to this problem, Wilkins discusses an inflatable plastic shield over the instrument panel that may help to somewhat reduce the amount of smoke between the operator and the panel. Alternatively, a separate, head mounted display could directly provide the crew members with critical flight information. For situations in which the visibility is reduced to less than a few centimeters and in order to prevent eye irritation because, such a display is preferably combined with some sort of smoke goggles. This latter approach is then, within certain limits, also suitable for situations in which the smoke contamination is strong and the instrument representation has to be very close to the human eye. 
     The above-mentioned solutions fail to suggest an appropriate integrated safety device approach. Such a safety device should allow the wearer in emergency situations not only to have access to certain information, but to indeed pilot an aircraft if the view is completely blurred and if the surrounding air is contaminated or toxic. It should, in addition, be possible to be made independent of the cockpit power supply in the case of a power failure or a deliberate switching off of the power supplies during emergency procedures. 
     SUMMARY OF THE INVENTION 
     It is a purpose of the present invention to provide an emergency flight safety device that overcomes disadvantages of present safety devices and especially enables the pilot to safely land an aircraft which is troubled by a smoke incident. 
     The emergency flight safety device according to the invention comprises a full-face mask with a see-through, multifunctional display. The device may be quickly deployed, and therefore allows immediate control over the aircraft by the cockpit crew in the case of an emergency. The integration of the head-mounted display into the full-face mask prevents smoke from disturbing the clear perception of displayed information and avoids eye irritation. It provides an undisturbed vision and access to flight information data as well as safe breathing conditions. Each display area covers a substantial part of the person&#39;s field of vision. Therefore, from relevant data such as track, position, speed, altitude and the position of the aircraft in the three dimensional space (inertial navigation data), the pilot can control the aircraft even if he does not see anything of the real world outside at all. By providing this display covering a substantial part of the pilot&#39;s view and by providing the opportunity to incorporate stereoscopic vision of visualized data, such as a virtual flight path to an emergency landing strip, in bad weather conditions or at night time by means of an infrared camera placed outside the cockpit, this device is a first step to a virtual cockpit. 
     In case of the development of health-critical smoke it is important to have access to purified air when cabin air pressure is relatively high. An increasing volume of surrounding cabin air in standard oxygen demand systems is mixed with a decreasing volume of oxygen as soon as the cabin pressure is approaching standard atmospheric pressure (cf Stünkel). The use of such a standard oxygen demand system would thus lead to the intoxication of the crew in case of the development of health critical smoke. The emergency flight safety device according to the invention therefore further comprises an oxygen and air supply apparatus for supplying oxygen and/or air to the interior of the mask i.e. a powered purified air respiratory system, which ensures that no intoxicated air gets into the mask. 
     In a preferred embodiment of the invention, the multifunctional head-mounted display is structured into a virtual area where critical flight information data is displayed and an area where real data such as video images obtained by an external camera can be overlaid onto critical flight information data, enhancing the perception of an actual situation, especially in the final phase of an emergency landing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following, an exemplified embodiment of the invention is described in more detail with reference to the attached drawings. In the drawings, 
     FIG. 1 shows a view of a person wearing a full-face mask according to the invention, comprising an oxygen and purified air supply, of an emergency flight safety device, 
     FIG. 2 is a view similar yet more schematic view of a person wearing a full-face mask, additionally showing a simplified scheme of the means for supplying and processing flight data, 
     FIG. 3 is a schematic representation of the functions of the device according to the invention with a display panel as seen by the crew member using the device, and 
     FIG. 4 schematically shows in section a person wearing a full-face mask according to one embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The emergency flight safety device described in the following is designed for installation in an aircraft, namely an airplane. A full-face mask  1  belonging to the emergency flight safety device is illustrated in FIG.  1 . It is mounted in an airplane cockpit, for instance contained in a dropout package, and can be automatically made available for the cockpit crew in case of an incident such as a sudden cabin-pressure loss, similar to the existing oxygen masks in airplanes. 
     The full-face mask  1  is configured to effectively shield the entire face of a person  3 , e.g., a crew member, from possibly intoxicated cockpit air. It covers essentially the whole face of the person  3  and has an elastically deformable margin section  5  for a smooth yet sealing skin contact. Straps  7  with adjustment buckles  9  serve as means for holding the mask on crew member&#39;s face. A view-through section  11  consists of transparent material and allows the person wearing the mask an essentially undisturbed perception under normal conditions, i.e., if the view in the cockpit is not blurred. A nose covering  12  divides the space between the mask  1  and the crew member&#39;s face into a viewing space and a breathing space which hermetically includes nose and mouth of the crew member. The mask  1  further comprises a purified air and oxygen supply joint  13  to which a conduit  14  is mounted. This conduit  14  is connected to valve means comprising an oxygen demand valve  15 , which in turn is linked to at least one oxygen container and/or oxygen generator  16 . The oxygen containers and/or the oxygen generator  16  are of the type used for passenger oxygen masks in existing airplanes. A pressure-reducing valve  17  may be inserted between an oxygen container  16  and the oxygen demand valve  15 . The oxygen demand valve  15  is further linked to a powered purified air respiratory device  18 . This powered purified air respiratory device comprises filtering means  19  for the filtering of possibly intoxicated cabin air. The oxygen demand valve  15  is configured to switch between supplying the person wearing the mask with oxygen or purified air. The switching may be carried out manually, but the oxygen demand valve  15  may also comprise means for the switching to be carried out automatically, e.g. depending on the pressure loss in the cockpit. As an alternative, the oxygen demand valve may be configured to provide a mixture of oxygen and purified air, the mixing ratio depending on the cockpit air pressure. The conduit  14 , the oxygen demand valve  15 , the oxygen containers and/or the oxygen generator  16 , the pressure reducing valve  17  and the powered purified air respiratory device  18  together constitute an oxygen and purified-air supply tool  14 - 18 . Air and/or oxygen to be inhaled enters from said tool  14 - 18  through the purified air and oxygen supply joint  13  into the viewing space from where it gets through valves  21  into the breathing space. Air outlets  23  with valves allow the exhaled are to get to the outside. 
     The view-through or see-through section  11  of the mask  1  comprises a see-through, multifunctional display  31 . The emergency flight safety device is, as schematically shown in FIG. 2, preferably equipped with means  32  for processing of flight data, e.g., a microprocessor or a computer. The thus-processed flight data is submitted by control instruments, such as a GPS/DGPS signal receiver  35 , an inertial flight navigation system  36 , an aircraft safety data controller  37  or a radio communication interface  38 . The emergency flight safety device also comprises means for transmitting flight data from the data processing means  32  to the display  31 , e.g., at least one transmission cable  33  connecting the microprocessor or computer  32  and the display  31 , the cable  33  being preferably attached to the conduit  14 . The display  31  is configured as a liquid-crystal display operated in a projection mode, using adjustable transmission. It preferably consists of two display areas  35 ,  37  that can be placed in front of and in close proximity to the left and the right eye of the person  3  wearing the mask  1 , respectively. In this case, both display areas  35 ,  37  show essentially the same, slightly shifted display image, providing binocular vision. 
     As an alternative to the liquid crystal display, a Direct Laser Beam Writing on the Retina (or Retinal Scanning Display, hereinafter “RSD”) can be used. RSD technology is based on the principle that light from a light source with colour determining means is directly, or by an intermediate image, projected onto the retina. In the present set-up, as schematically represented in FIG. 4, a coloured light beam from a laser light source  101  placed behind a plane in front of the eye is projected onto an area with a semitransparent mirror  105  placed in close proximity in front of the eye. By deflection means  103 , two-dimensional scanning is achieved. The reflected part  111  of the laser beam is projected onto the retina  113 . In this way, an impression of an image covering an (effective) display area is created. The semitransparent mirror may, as an example, be a part of or placed on the view through section  11 . The mirrored area thus does not obstruct the person&#39;s vision. In the figure, only one RSD set-up for the left eye only is shown. Of course, also an RSD set-up for the right eye may be present. In this way, even a three dimensional impression can be created, if required. 
     In both cases, if the integrated display is an LCD display or if it is made up of a RSD set-up, it is important that the display areas cover a substantial part of the person&#39;s field of vision. This means, that the display area e.g. includes, if the person looks straight ahead, a central part of the field of vision and extends, as an example, from a region left of a vertical middle line to a region right of the vertical middle line. A substantial part is also covered if about 15%, preferably 25% or even at least 35% of the person&#39;s field of vision is covered by the display area if the person looks straight ahead. 
     Two (real or effective) display areas  35 ,  37  together define one image for the person  3 , which is at least partially superposed to the actual view as seen by the person  3  through the view-through section  11  of the mask  1  and which defines a virtual display area  41  as shown in FIG.  3 . This virtual display area  41  is used to show GPS (Global Positioning System) and/or DGPS (Differential Global Positioning System) data  43  such as position, track, speed and altitude, giving information about the current position of the aircraft and its track to an emergency landing position. Flight safety system data  45  of the aircraft, such as fire prevention information, power management conditions, and communication frequencies, may also be displayed in the virtual area  41  of the display  31 . A center section  40  of the virtual display area  41  is preferably designed as a see-through section used to display data  47  produced by an inertial navigation system, thereby informing the crew about the orientation of the aircraft in the three dimensional space similar to an artificial horizon. 
     An external imaging device  34 , e.g., a camera, can also be part of the emergency flight safety device according to the invention. It can have a visual and/or infrared spectral sensitivity, the latter enhancing visibility in bad weather conditions or at night. This camera  34  is preferably mounted on the bottom side of the airplane such that its field of vision is essentially equivalent to the field of vision of a person viewing through the cockpit window. During an emergency landing, if the view in the cockpit is blurred by smoke, the camera  34  is used to supply real time image data showing the ultimate landing situation, if necessary under enhanced night vision condition. The real time image data may also comprise runway lights, obstacles and/or visual glide path information (Visual Approach Slope Indicator, VASI, or Precision Approach Path Indicator System, PAPI). The image obtained by the camera  34  is shown on the same center section  40  of the virtual display area  41  as the inertial navigation system data  47 . Other sensors such as speed or altitude sensors may form part of the emergency flight safety device in the same way as the camera  34 . 
     Preferably, the data displayed on the virtual display area  41  depend on the situation, such as the light conditions, the cockpit atmosphere, etc. 
     A flight-safety device that works efficiently in various emergency scenarios, such as engine failure, fire, smoke, health-critical fume, electrical failure, and also in deliberate actions under emergency conditions must be powered by a redundant power source that is independent of the main aircraft power source. For this purpose, the emergency flight safety device according to the invention preferably has an auto-power function carried out by an independent and redundant power source  51  (see FIG.  2 ). The mask  1 , the oxygen and purified air supply device  14 - 18  as well as the sensors such as GPS/DGPS  35 , inertial navigation system  36 , the aircraft safety system data controller  37 , the radio corn interface  38 , and the outside camera  34 , are included in this independent power management concept. If the sensors are also used by other applications than the emergency flight safety device, their redundant availability is assured by additional independent equipment. 
     The embodiment described above is by no means the only embodiment of the invention and can be altered or supplemented in many ways. As an example, the means for transmitting data to the display does not have to comprise cables, it can also be equipped with a radio or similar transmission apparatus. In addition to the display  31 , also communication equipment such as a headset and a microphone can be integrated in or attached to the full-face mask  1 . The mask  1  can further comprise means for the adaptation of the display positioning to the crew member&#39;s head size. The crew member&#39;s data may even be stored in the computer belonging to the transmission tool so that the exact positioning of the two display areas  35 ,  37  on the mask  1  can be automatically adapted to the eye position and spacing. 
     The emergency flight safety device may further be equipped with intelligent means for the matching of the gas composition in the mask to the crew member&#39;s needs, which means may comprise sensors mounted on the inside of the full-face mask  1 .