Method for approaching a platform

0001The present invention relates to a method for driving an aircraft on a platform, and in particular a short landing aircraft such as an aircraft equipped with a rotary wing for example.

0002The invention is therefore in the technical field of aircraft flight assistance systems, including automated systems for approaching platforms for rotorcraft.

0003Indeed, a rotary wing aircraft must be able to find and approach safely mobile platforms or vessels, regardless of weather conditions and visibility and avoiding obstacles in the approach area.

0004The approach is conducted taking into account the direction and wind speed in the sector, the type of platform to approach (fixed platforms, mobile, boats or barges), surrounding obstacles (cranes, barges, boats used for positioning the platform, container-type boats or "super tanker" sailing around the approach zone, or other surrounding platforms), passenger comfort.

0005Platform approaches typically consist of the following flight segments.

0006Thus, the approach includes an arrival segment that connects the last flight point of the current flight phase and an initial approach point known by the acronym "IAF" is "Initial Approach Fix" in English. This arrival segment is generally positioned at an altitude of 1500 ft. It is recalled that the symbol "ft" refers to the unit of length called "feet" in the English language, equal to 30.48 centimeters.

0007An initial approach segment may connect the initial approach point IAF to an intermediate point known as IF, or Intermediate Fix in the English language. This initial approach segment aims to allow the aircraft to decelerate and align with the trajectory to follow.

0008An intermediate approach segment may connect intermediate point IF to a final approach point known as "FAF" or "Final Approach Fix" in English to descend to an altitude of up to 1000 ft. This segment aims to align the aircraft, decelerate and prepare the final approach segment.

0009At least one final approach segment connects the FAF final approach point and a known decision point under the acronym "MAP" or "Missed Approach point" in the English language.

0010For example, the final approach point FAF is connected to the decision point MAP via a bearing point LPO and an offset point OIP.

0011If a pilot makes visual contact with the platform at the decision point, the pilot may place the aircraft on that platform.

0012On the other hand, a so-called go-around segment must be conducted if visual contact with the platform is not obtained at this stage of the approach. This go-around segment may also be conducted at any point during the approach if the crew deems it useful. The purpose of this go-around segment is to reach a safe altitude.

0013The final descent from the final approach point to the MAP decision point shall only be carried out in the absence of obstacles in a 2-nm corridor. It is recalled that the symbol "nm" refers to the unit of length denominated "nautical mile" in English language worth 1852 meters.

0014If obstacles are present in this lane, the approach procedure can be canceled for safety. Detecting such obstacles can be tricky. Indeed, a crew may have difficulty assessing whether the presence of a moving ship is likely to terminate the approach procedure.

0015The following documents present known approaches to platforms:<ul><li>AC90-80B <nplcit id="ncit0001" npl-type="s"><text>"Approval of Offshore Standard Approach Procedures, Airborne Radar Approaches, and Helicopter En Route Descent Areas" published on 12.04.99</text></nplcit></li><li>JAR OPS 3, Section 2, Subpart IEM to Appendix 1 to JAR-OPS 3.430 sub-paragraph (d) (Amendment 2, published 01.01.02).</li><li>EU-OPS COMMISSION REGULATION (EU) No 965/2012 of 5 October 2012 (AMC1 CAT.OP.MPA.120 and GM1 CAT.OP.MPA.120),</li><li>the CAA paper <nplcit id="ncit0002" npl-type="s"><text>2010/01 "The SBAS Offshore Approach Procedure (SOAP)</text></nplcit>".</li></ul>

0016When weather conditions are unfavorable, an instrument approach is conducive to the stress of the crew who must manually pilot the aircraft to guide it to an area where the visual acquisition of the platform will be obtained.

0017In the transition from the instrument phase to the visual flight phase, the attention of the crew must constantly switch between what is displayed on the dashboard control screens and what it observes at the outside to detect any sign / visual index to confirm the position of the platform (light, relief). This way of approaching on a platform is therefore not the most practical and can sometimes create misinterpretation in the event, for example, of fog temporarily losing the visual acquisition of the landing target.

0018Instrument approaches to a platform or moving vessels have heretofore been conducted without the use of a navigation computer, known by the acronym "FMS" or "Flight Management System" in English, and without driver coupling. the aircraft on an approach path predefined by the FMS.

0019Some platforms are now equipped with a device, known by the acronym "NDB" or "Non Directional Beacon" in English, used by the crew via the navigation computer as a means of navigational aid and correlation of the position of the aircraft with relative accuracy but this means does not allow the construction of an approach flight plan.

0020A navigation computer used to provide horizontal guidance during the en-route phase is known. For the approach phase, the crew determines an off-road target point corresponding to the coordinates of the platform to be reached as a means of navigational aid. However, the navigation computer does not segment the different phases of the approach to the platform to slave the autopilot on these guidance data (horizontal deflection, vertical deviation, speed reference).

0021The approach is then conducted manually or semi-automatically via the assistance of certain higher modes of the autopilot using the approach charts published by the operators and approved by the local authorities.

0022The weather radar of the aircraft can also be used as a means of identification of the platform, detection and transient or fixed obstacle avoidance during the approach and the final descent.

0023The document <patcit id="pcit0001" dnum="US20100168939A"><text>US 2010/0168939</text></patcit> proposes a module and an automated method for approaching a platform on an approach trajectory constructed from approach points.

0024According to this document <patcit id="pcit0002" dnum="US20100168939A"><text>US 2010/0168939</text></patcit>, a pilot enters into a module of the aircraft:<ul><li>the coordinates of the target platform to be reached,</li><li>a final approach course towards the platform,</li><li>an offset distance laterally separating the trajectory to follow from a trajectory directed towards the platform following this approach heading,</li><li>a descent height.</li></ul>

0025Consequently, the aircraft module determines in particular the position of the initial approach point IAF and the final approach point FAF in response to the data entered. The aircraft is then directed to the initial point of approach.

0026Thus, the constructed approach path comprises a horizontal segment connecting an initial approach point IAF to a final approach point FAF.

0027Then, the path includes a descent segment and then a level segment to connect the final approach point FAF to a decision point MAP.

0028The initial approach point IAF, the final approach point FAF and the decision point MAP are contained in a vertical plane parallel to the chosen approach heading. It is understood that the term "vertical plane" a plane directed according to gravity, points of this vertical plane may be at different altitudes.

0029This vertical plane is offset from the platform by a distance equal to the offset distance entered.

0030The document <patcit id="pcit0003" dnum="US7016772B2"><text>US7016772 B2</text></patcit> unveils an information display device on vehicles according to their importance (size, position, speed), and unveils a ship system that combines radar information with information from an automatic identification system known as 'acronym' AIS 'means' Automatic Identification System' in the English language.

0031The document <patcit id="pcit0004" dnum="US8296001B1"><text>US8296001 B1</text></patcit> unveils a system that assists a navigator by giving the characteristics of other boats and coastal information. A radar or AIS system can be used.

0032The document <patcit id="pcit0005" dnum="JP3763004B"><text>JP3763004 B1</text></patcit> describes a system for protecting a descent plane when approaching aircraft to an airport vis-à-vis ships using an AIS system.

0033The technological background also includes the following documents:<ul><li>Esterline CMC Electronics, CMA-9000 Flight Management System Operator's Manual, Operational Program S / W 169-614876-022, Publication No. 9000-GEN-0105, itel N). 930-6000088-00, august 21.2008</li><li><nplcit id="ncit0003" npl-type="s"><text>N.McFarlane, A new procedure for North Sea Helicopter Operations, Second GIANT use forum, Brussels, Belgium, October 9, 2008</text></nplcit>,</li><li><nplcit id="ncit0004" npl-type="s"><text>KM Dodson and JRA Stevens, A North Sea Trial to Investigate Differential GPS for Instrument Approaches to Offshore Platforms, paper presented at the 23rd European Rotorcraft Forum, Dresden, Germany, September 1997</text></nplcit>,</li><li>The documents <patcit id="pcit0006" dnum="EP2249126A"><text>EP 2249126</text></patcit>, <patcit id="pcit0007" dnum="GB2492665A"><text>GB 2492665</text></patcit>, <patcit id="pcit0008" dnum="FR2943778"><text>FR2943778</text></patcit>.</li></ul>

0034The present invention therefore aims to provide an approach method to help a crew to land on a platform with an aircraft.

0035According to the invention, defined by the claims, a method for facilitating the approach of a platform present on a liquid surface with an aircraft comprises a development phase to develop an approach path to a theoretical position of said platform.

0036In addition, this method includes a consolidation phase and may include a security phase.

0037During the consolidation phase of said approach trajectory:<ul><li>The current position of said platform is determined,</li><li>A distance separating said theoretical position from said current position is determined,</li><li>An alarm is triggered when said distance is greater than a first threshold,</li></ul>

0038During the security phase of said approach trajectory:<ul><li>The current position as well as the direction of movement and the speed of movement of the objects equipped with an automatic identification system which are present in a predetermined monitoring zone are determined over time,</li><li>A danger level of each object is determined with respect to the approach trajectory followed,</li><li>∘ a horizontal representation of said approach trajectory is displayed on a display screen, as well as for each object: a plot representing the current position of the object, an indication of the direction of movement of the object, and a relative representation at the level of danger of the object.</li></ul>

0039The monitored objects can be floating objects and / or flying objects.

0040The development phase can be undertaken automatically by a navigation computer, from input data including the theoretical position of the platform and an approach course such as a course to follow, for example. Reference will be made to the literature on the approach procedures that can be generated.

0041The theoretical position can be entered by an operator, or it can come from a database of platforms. This database includes for example an identifier of the platform and these coordinates. Other information may be present, such as a radius of each platform including considering that each platform is contained in a circle.

0042The consolidation phase proposes to compare the theoretical position of a target platform that has made it possible to establish the approach trajectory at a current position of this target platform. Thus, a radar signal or a signal known by the acronym AIS referring to an automatic identification system makes it possible to obtain a "measured" current position of the target platform.

0043If the distance separating the theoretical position from the current position is less than a first threshold, it is considered that the coordinates of the theoretical position are exact. The first threshold may be of the order of 0.1 Nm.

0044On the other hand, if not, an alarm is generated to warn the crew and point out a possible problem. It will be seen later that the crew can then be diverted or can recalibrate the approach path to a new position of the platform, the current position for example.

0045It is understood that the aircraft performs measurements at a given frequency. For example, the aircraft can report positions transmitted by automatic identification systems every 6 seconds during a forward flight.

0046Therefore, an alert can be generated only if a plurality of measurements confirms the offset present between the theoretical position and the measured current position.

0047The consolidation phase can be performed automatically and in real time by a computer, such as a map calculator known by the acronym DMAP communicating with the navigation computer.

0048This consolidation phase makes it possible to secure the approach favorably.

0049Moreover, this method can implement a security phase. Certain regulations require the aircraft to follow an approach path present in a 2 nm wide approach corridor centered on this approach path, this approach corridor must not contain any obstacle.

0050It may be difficult to check this point during an instrument flight in harsh weather conditions using only weather radar as the primary means of obstacle identification and detection. The security phase tries to remedy this for obstacles including automatic identification systems.

0051These automatic identification systems transmit information to the aircraft relating to the obstacle, such as its position and its speed vector. Using this information, the danger of the obstacle is determined by determining the risks of conflict between the trajectory of the aircraft and the trajectory of the obstacle. This operation is for example performed for each obstacle present in the surveillance zone considered. Therefore, it displays on a display screen the approach path followed by the aircraft, as well as identifiers visually to determine the position of an obstacle, the movement performed by the obstacle, the dangerousness of the obstacle by compared to the calculated approach trajectory even the predictive position of the obstacle to the

0052Using this information, an aircraft crew member can establish an alternative approach course if an obstacle is likely to be present in the current approach corridor. The aircraft can also divert if necessary.

0053This method may further include one or more of the following additional features.

0054Thus, during the consolidation phase and if the distance separating the theoretical position from the current position is less than a second threshold, the theoretical position of the platform can be manually modified. The second threshold may be greater than the first threshold.

0055For example, the theoretical position of the platform is modified to minimize the distance separating it from the current position taken up, making it coincide with the current position, if any. The new theoretical position is then used to establish the approach path, for example by a navigation calculator.

0056For example, you can choose a new theoretical position using a cursor displayed on the display screen, such as a cross of Saint Andrew for example. This slider can point to the current position displayed on this display screen for example. We can also enter a distance and an axis on a navigation computer to recalibrate the theoretical position of the platform. Finally, we can use an automatic AIS identification system of the platform to recalibrate the theoretical position of the platform on its AIS coordinates.

0057Note that the registration of the platform is allowed only if the determined distance is less than the second threshold, of the order of 0.3 nm for example. This feature aims to avoid a random registration in case of too large difference between the theoretical position and the current position.

0058As a variant, the registration may be authorized independently of the value of this distance.

0059This registration can induce an automatic calculation of a new approach trajectory.

0060Thus, a vector connecting the theoretical position of the platform to a new target position is automatically determined, and the approach trajectory is automatically shifted by applying this vector to it to rally to said new position.

0061Re-registration may be prohibited if it occurs too late in the approach procedure. The manufacturer may determine an approach point from which registration is prohibited.

0062Moreover, we can start the consolidation phase as soon as we receive information providing the current position of the platform. For example, the consolidation phase begins when the aircraft receives information from an automatic system for identifying the platform.

0063In addition, the predetermined monitoring zone is possibly a circle of a radius defined by the manufacturer centered on the platform to be reached.

0064This radius can correspond to the length separating an initial approach point IAF from the target platform plus a constant, of the order of 0.5 nm for example.

0065In addition, it is possible to display on the display screen an approach corridor of a given width centered on said approach path. The width may be 2 nm according to certain regulations. The approach corridor can then be the approach corridor described in these regulations, possibly extended locally for safety.

0066In addition, the approach path may include a final approach point FAF Therefore, during the security phase, the approach path passing through a final approach point FAF, before this final approach point FAF is reached by the aircraft:<ul><li>the time required for said aircraft to reach this final approach point FAF is determined,</li><li>the predictive position of each of said objects will be determined when said aircraft reaches the final approach point,</li><li>the level of danger of each object is determined according to its predictive position and its current position with respect to an approach corridor of a given width centered on said approach path.</li></ul>

0067For example, a first, a second and a third level of danger are implemented, an object being associated with:<ul><li>at the first level of danger when the current position of that object is not situated in the approach lane and when its predictive position will not be located in said approach lane when said aircraft has reached the final approach point,</li><li>at the second level of danger when the current position of that object is not situated in the approach lane and when its predictive position will be in the approach lane when the said aircraft has reached the final approach point,</li><li>at the third level of danger when the current position of that object is in the approach lane and when its predictive position will be in the approach lane when the aircraft has reached the final approach point</li></ul>

0068If an object presents the first, the second, or the third level of danger, one displays respectively a first, a second or a third representation. For example, each representation corresponds to the color of the plot. A white colored stud may indicate a non-dangerous object with the first level of danger, a shaded or colored amber stud may indicate a possibly dangerous object with the second level of danger, and a red or black colored stud may indicate a dangerous object presenting the third level of dangerousness.

0069Moreover, depending on the detected objects, it is possible to authorize a change of course of said approach path during an elaboration phase of an alternative approach path.

0070In the presence of dangerous objects for example, an operator develops an alternative approach trajectory by choosing a new approach run. If the approach path has a segment shifted to the right of the platform relative to an initial segment, the operator can also choose a shift to the left of this platform, and vice versa.

0071The first developed approach course and the alternative approach course on the display screen can be displayed with separate representations to facilitate the development of the alternative approach course.

0072For example, the current approach path is displayed in full line, and the alternative approach path in dashed lines. The alternate approach corridor can also be displayed.

0073In addition, during the securing phase, the approach course passing through a FAF final approach point, after this FAF final approach point is reached:<ul><li>the current position as well as the predictive position based on the direction of movement and the speed of movement of the objects referred to as "intruders" situated in front of said aircraft or in a circle centered on said aircraft and having a predetermined diameter, are determined over time,</li><li>for each intruder and over time:<ul><li>Determining whether said intruder is at a current time located in an approach corridor surrounding said approach trajectory and if said intruder is located in front of the aircraft,</li><li>∘ if the said intruder is not present in the approach corridor and if the said intruder is in front of the aircraft, it is determined whether the intruder will enter the approach corridor in the future, and if so, when said intruder enters the approach corridor,</li><li>Said intruder is associated with a first level of danger represented by a first representation on the display screen when said intruder is behind the aircraft at a current time or when said intruder will be behind the aircraft when he enters said corridor approach,</li><li>Said intruder is associated with a second level of danger represented by a second representation on the display screen when said intruder is in front of the aircraft when he enters said approach corridor,</li><li>Said intruder is associated with a third level of danger represented by a third representation on the display screen when said intruder is in front of the aircraft in said approach corridor at the current time.</li></ul></li></ul>

0074Normally, no obstacle should be in the approach lane at this stage. However, a ship or aircraft may have changed course, and this process can be used to estimate a hazard not originally anticipated.

0075This procedure makes it possible to quantify the possible risks linked to such obstacles.

0076In addition, according to a variant:<ul><li>a mobile box representing a quadrilateral of a predetermined fixed width and of a length equal to the product of a time constant and the ground speed of the aircraft is displayed on the display screen, the mobile box being centered transversely on the velocity vector of the aircraft and extending longitudinally from a representation of the aircraft,</li><li>the current position as well as the direction of displacement, the speed of movement and the predictive location at the end of said time constant of the objects referred to as "close element" located on said liquid surface equipped with an automatic system are determined over time which are present in a predetermined scanning zone centered on said aircraft,</li></ul><ul><li>one displays on the screen of visualization for each element close together:<ul><li>∘ a first symbology when the current position and the predictive location are not located in the mobile box,</li><li>A second symbology when the current position is not located in the mobile box and when the predictive localization is located in the mobile box,</li><li>A third symbology when the current position is located in the mobile box and when the predictive localization is not located in the mobile box,</li><li>A fourth symbology when the current position and the predictive location are located in the mobile box.</li></ul></li></ul>

0077The mobile box allows to provide information to a pilot about the upcoming situation in the short term.

0078This warning information on the potential risk of interference between the trajectory of the aircraft and the trajectory of the moving obstacle can take into account either the current speed of the aircraft or the speed instructions followed by default by the aircraft. aircraft along the predicted course of approach.

0079It is recalled that each object is schematized on the display screen using the following visual identifiers: a plot, an indication of the direction of movement of the object and a representation relating to the level of danger of the object through staining of the plot for example, or even an indication of a predictive position of the object at the end of a given time. This indication of the direction of movement may be an arrow whose length depends on the speed of movement of the object, the arrow may lead to a predictive position of the object at the end of a given time predetermined by the manufacturer.

0080The aforementioned symbologies may comprise identifiers of another type, or may consist of modifying at least one of these identifiers.

0081For example, the first symbology may not modify said identifiers. On the other hand, the second symbology can make the arrow flash, the third symbology can make a pad flash, and the fourth symbology can make the pad and the arrow representing an object flash.

0082The invention and its advantages will appear in more detail in the context of the description which follows, with exemplary embodiments given by way of illustration with reference to the appended figures which represent:<ul><li>the <figref idrefs="f0001">figure 1</figref>, a diagram showing an aircraft implementing the method according to the invention,</li><li>the <figref idrefs="f0001">figure 2</figref>, a diagram explaining the security phase when the aircraft has not reached the final approach point,</li><li>the <figref idrefs="f0002">figure 3</figref>, a diagram explaining the security phase when the aircraft has reached the final approach point,</li><li>the <figref idrefs="f0002">figure 4</figref>, a diagram explaining the consolidation phase,</li><li>the <figref idrefs="f0003">figure 5</figref>a diagram showing the displayed mobile box, and</li><li>the <figref idrefs="f0003">figure 6</figref> a vertical representation of the trajectory followed.</li></ul>

0083The elements present in several separate figures are assigned a single reference.

0084The <figref idrefs="f0001">figure 1</figref> presents an aircraft 1 capable of implementing the method according to the invention.

0085This aircraft may comprise a navigation calculator 2, such as a computer commonly known by the acronym "FMS" and the English expression "Flight Management System".

0086This navigation calculator 2 can communicate with a database 3 listing platforms and certain characteristics of these platforms.

0087In addition, the navigation computer is in communication with an automatic guidance device 10 capable of guiding the aircraft along an approach path developed by the navigation computer.

0088This navigation calculator can generate an approach trajectory to reach a target and in particular a platform floating on a liquid surface, and can transmit instructions to the automatic guidance device so that the aircraft is guided on this approach path. .

0089Moreover, the aircraft 1 is provided with a cartographic calculator, such as a calculator known by the acronym "DMAP" or the English expression "Digital Map".

0090The cartographic calculator 4 is connected to automatic identification system 5 known by the acronym "AIS" or the English expression "Automatic Identification System". The automatic identification system 5 can receive AIS signals from objects equipped with a similar system. These AIS signals can provide the current latitude and longitude of the object, its speed of movement, its direction of movement, its height, its draft ...

0091The cartographic calculator 4 can be connected to an automatic identification system 5 known by the acronym "TCAS" or the English expression "Traffic Collision Avoidance System". The automatic identification system can receive TCAS signals from other aircraft equipped with a similar system. These TCAS signals can provide the distance between the aircraft and the intruder aircraft, as well as the following information relating to the intruding aircraft: altitude, vertical speed, relative run, current latitude and longitude, and the movement speed.

0092It will be understood that the aircraft may comprise an automatic identification system 5 using AIS technology and / or TCAS technology in particular.

0093In addition, the cartographic calculator 4 can communicate with a radar system 6 so as to receive echoes from radars and commonly referred to as "radar echoes".

0094The cartographic calculator 4 is able to generate displays presenting in particular the radar echoes received and the objects identified by the automatic identification system 5.

0095The navigation computer 2 and the cartographic calculator 4 are in communication with a display device 7. The display device is provided with a display screen and buttons 9 or equivalents that can be operated by an operator. With the aid of these buttons 9, an operator can transmit instructions or information to the navigation computer 2 and to the cartographic calculator 4.

0096Other architectures are possible. For example, the automatic identification systems can be interfaced directly with the navigation computer 2 or with the display device 7.

0097With reference to the <figref idrefs="f0001">figure 2</figref> and during a development phase, an operator manipulates the buttons 9 to allow the navigation computer to develop an approach path 25.

0098For example, the operator chooses the target platform to be reached among the platforms stored in the database 3, a race CRS1 to be followed to reach the target platform, a height value relative to a minimum decision altitude for descent into final approach to said target platform such as a minimum descent altitude (MDA) to be reached for leveling following the final descent phase, an offset side to determine where the platform should be in relation to the aircraft at a decision point MAP.

0099The navigation calculator then develops an approach path 25 to follow to reach the target platform according to the attributes of the platform present in the database 3, and parameterized information. This approach path 25 is displayed on the display screen in addition to the information displayed following the instructions of the cartographic calculator.

0100The approach path may include an initial approach point IAF, a final approach point FAF, an offset point OIP and a decision point MAP based on said information and said attributes.

0101Optionally, an intermediate approach point IF and a bearing point LPO are also determined.

0102The initial approach point IAF, the final approach point FAF, the OIP offset point, the coordinates of the target platform, and if appropriate the intermediate approach point IF and the bearing point LPO are arranged in a same vertical plane. This vertical plane is directed according to the set CRS1 race.

0103On the other hand, the decision point MAP is shifted with respect to this vertical plane. It is recalled that the shift to the left or right of the decision point relative to the vertical plane is optionally configurable.

0104According to <figref idrefs="f0003">figure 6</figref>, the MAP decision point, the OIP offset point, and if necessary the LPO bearing point are arranged at an altitude equal to the MDA decision minimum altitude.

0105It is understood that the invention however applies to other types of approach paths.

0106With reference to the <figref idrefs="f0002">figure 4</figref>, the cartographic calculator can then implement a consolidation phase.

0107Thus, the current position 20 "of the platform 20 is determined using, for example, the cartographic calculator 4.

0108For example, this map calculator 4 uses the signals from the automatic identification system 5 or the radar system 6.

0109This step can be performed at a predetermined location with respect to the theoretical position 20 'of the target platform, or upon receipt of information providing the current position 20 "such as an AIS signal from the platform 20.

0110Therefore, the distance D1 separating the theoretical position 20 'from the current position 20 "is determined, and a visual and / or audible alert is triggered when this distance D1 is greater than a first threshold S1 These steps can be undertaken by the calculator map, the alert being generated for example by the display device 7.

0111If the distance D1 is less than the second threshold S2, the manual modification of the platform position 20 is authorized.

0112For example, an operator uses a button 9 to point a geometric location on the display screen to signal the navigation calculator the new position of the platform to take into account.

0113According to the method, a vector 45 is automatically determined which links the theoretical position 20 'to the new position 20 ", and the approach trajectory 25 is automatically shifted by applying to it said vector 45 to define a new approach path. For example, the cartographic calculator transmits the new theoretical position to the navigation calculator which calculates the vector to be applied and thus develops the new trajectory.

0114With reference to the <figref idrefs="f0001">figure 2</figref>, on the display screen is displayed a horizontal representation of the approach path to follow. It should be noted that it is also possible to display an alternative approach trajectory 25 'being developed. Two distinct trajectories are represented in a different way to facilitate their visualization.

0115The display screen 8 can also display a vertical representation of the type of the <figref idrefs="f0003">figure 6</figref>.

0116With reference to the <figref idrefs="f0001">figure 2</figref>for example, it can be noted that the cartographic calculator may require, in addition, the display of an approach corridor 50 of a given width 51. The approach corridor 50 is centered on the approach path 25 to follow. This approach corridor may correspond to the corridor defined by certification regulations

0117The approach corridor may possibly have dimensions greater than the dimensions required by the regulations at least locally for safety. For example, the approach corridor may comprise a straight segment 50 'of the final approach point FAF at the OIP offset point, and then an inclined segment 50' from this OIP offset point. can also be extended beyond the OIP offset point.

0118In addition or alternatively, a phase of securing the approach path 25 is implemented.

0119Therefore, the current position as well as the direction of movement and the speed of movement of certain objects located on the liquid surface or in the air are determined according to a sampling frequency. More specifically, the cartographic calculator 4 cooperates with the automatic identification system 5 to list the objects 30 provided with an automatic identification system AIS, TCAS and present in a predetermined OCZ monitoring zone.

0120The OCZ surveillance zone shown on the <figref idrefs="f0001">figure 2</figref> is a circle of radius R1 centered on the platform 20 to reach.

0121Therefore, a danger level of each object is determined with respect to the approach trajectory followed according to rules defined by the manufacturer.

0122Then, on the display screen 8 is displayed the horizontal representation of the approach trajectory 25 as well as for each object: a pad 41 representing the current position of the object, an indication 42 of the direction of movement of the object , and a representation 43 relating to the level of danger of the object. The indication 42 may be an arrow directed according to the speed vector of the object and having a length depending on the speed of advance of the object. This length can also take into consideration a given time, the arrow can thus indicate the predictive position of the object at the end of this given time.

0123The level of danger can be established by the cartographic calculator which communicates to the display device 7 the data to display and their symbology with possible generation of an audio alert according to the dangerousness.

0124The manufacturer can establish three levels of dangerousness displayed through a coloration of the studs 41. A first level of danger can induce a first type of coloration represented for example by a white color on the stud 31 of the <figref idrefs="f0001">figure 2</figref>. A second level of danger can induce a second type of coloration represented by one of the hatching on the pad 32 of the<figref idrefs="f0001">figure 2</figref>. Finally, a third level of danger can induce a third type of coloration represented by a black color on the stud 33 of the<figref idrefs="f0001">figure 2</figref>. On an aircraft and by way of example, the second type of coloration may be an amber color, the third type of coloration may be a red color.

0125Depending on the dangerousness of the objects taken into consideration, it is possible to authorize an elaboration of an alternative approach trajectory 25 'aimed at avoiding objects deemed dangerous. Thus, it is possible to authorize a change of course to move from an approach path aligned with a first race CRS1 to an alternative approach path aligned with a second race CRS2.

0126During the security phase, two distinct situations are distinguished, depending on the position of the aircraft with respect to the final FAF approach point.

0127Before this FAF final approach point is reached, the time TFAF is determined at which the aircraft will reach the final FAF approach point. This step can be undertaken by the cartographic calculator for example. For this purpose, the map calculator may be connected to devices for determining the ground speed of the aircraft.

0128Therefore, the cartographic calculator determines the predictive position of each object studied at the end of this time TFAF. Thus, the aircraft determines where the objects will be when this aircraft reaches the final approach point based on the information transmitted by their automatic identification system.

0129Therefore, the level of danger of each object is established according to its predictive position and its current position with respect to the approach corridor.

0130The cartographic calculator can thus give an object the first level of danger when the current position of this object is not located in the approach corridor 50 and when its predictive position will not be located in the approach corridor 50 at the TFAF time. The object marked by the stud 31 thus presents this first level of danger.

0131The second level of danger corresponds to an object having a current position outside the approach corridor 50, but which has a predictive position located in this approach corridor 50. The object marked by the stud 32 thus presents this second level dangerousness.

0132Finally, the third level of danger is associated with an object when its current position and its predictive position are located in the approach corridor 50. The stud 33 corresponds to the current position of such an object.

0133With reference to the <figref idrefs="f0002">figure 3</figref>, the system focuses on objects potentially located in front of the aircraft when the FAF final approach point is reached or exceeded, namely the objects located between the line 200 and the top of the sheet on which the <figref idrefs="f0002">figure 3</figref>.

0134Consequently, the current position as well as the direction of movement and the speed of movement of the objects referred to as "intruders" for convenience located either in front of the aircraft 1 or in a circle C1 centered on the aircraft 1 are determined over time. The circle diameter is small and smaller than the width of an approach corridor.

0135For each intruder and over time, it is determined according to a processing frequency whether the intruder is at a current time located in an approach corridor 50 and if this intruder is located in front of the aircraft 1. If the intruder is not present in the approach lane 50 and if the said intruder is in front of the aircraft 1, it is determined whether the intruder will enter said approach lane 50 in the future, and if so, when this intruder will enter the approach lane 50.

0136These steps can be undertaken by the map calculator.

0137Therefore, an intruder is given the first level of danger represented by a first representation 31 'on the display screen 8 when the intruder is behind the aircraft 1 at a current time, or when the intruder is behind the aircraft. when entering the approach lane 50, or when the intruder will never enter the approach lane.

0138The intruder is on the other hand associated with the second level of danger represented by a second representation 32 'on the display screen 8 when the intruder will be in front of the aircraft 1 when he enters the approach lane 50.

0139Finally, the intruder is associated with a third level of danger represented by a third representation 33 'on the display screen 8 when the intruder is in front of the aircraft 1 in the approach corridor 50 at the current time.

0140Moreover and with reference to the <figref idrefs="f0003">figure 5</figref>a moving box 55 can be displayed on request and on the display screen 8. This mobile box corresponds to the horizontal representation to a quadrilateral of a predetermined fixed width 56 and of a length 57 equal to the product of a constant of the time CTE and ground speed GS of the aircraft 1. The time constant may for example be chosen from a list predetermined by the manufacturer.

0141The mobile box 55 is centered transversely on the speed vector of the aircraft and extends longitudinally along this speed vector from a representation of the aircraft 1. The moving box therefore moves together with the representation of the aircraft. aircraft on the display screen.

0142When this option is enabled, some objects are associated with additional symbology. More particularly, the current position as well as the direction of displacement, the speed of movement and the predictive location at the end of said time constant are determined over time by objects referred to as "close elements" equipped with an automatic system. identification which are present in a predetermined scanning zone Z1 centered on the aircraft,

0143For each close element, we display:<ul><li>a first symbology when the current position and the predictive location are not located in the mobile box 55,</li><li>a second symbology when the current position is not located in the mobile box 55 and when the predictive localization is located in the mobile box 55,</li><li>a third symbology when the current position is located in the mobile box 55 and when the predictive location is not located in the mobile box 55,</li><li>a fourth symbology when the current position and the predictive location are located in the mobile box 55.</li></ul>

0144Thus, the stud 34 and the associated arrow 34 'remain unchanged according to the first symbology.

0145On the other hand, the arrow 37 'associated with the pin 37 may flash according to the second symbology.

0146In addition, the pad 35 may flash according to the third symbology, the arrow 36 'and the pin 36 flashing both according to the fourth symbology.

0147The frame of the mobile box may also have a particularity when the stud having the current position of an object is present in this mobile box. For example, the frame can become red.