FR2733597A1 - ON BOARD INSTRUMENT INTENDED TO CONTROL THE TANGING SPEED OF AN AIRCRAFT DURING TAKE-OFF - Google Patents

Abstract

The present invention relates to an on-board instrument for an airplane, and more particularly to an on-board instrument intended to control the pitch speed of said airplane during its take-off and to warn the pilot when this pitch speed deviates from a determined value during the phase. take-off rotation. This on-board instrument (1) comprises two comparators (41, 42) receiving the signal of the gradient of the pitch angle emitted by a sensor (6) and signals from reference sources (43, 44) indicating the safety gradients maximum and minimum pitch angle. The on-board instrument display (2) engages when the nose gear of the aircraft leaves the runway and displays a stationary symbol (22, 23) as long as the pitch angle gradient is at l. within the safety limits. When the pitch angle gradient falls outside these limits, the display (2) changes so that the symbol (22, 23) moves to warn the pilot. When the airplane has reached a certain height, the display device (2) of the on-board instrument is activated.

Description

INSTRUMENT FOR INSPECTING THE SPEED OF

  TANGING AN AIRCRAFT AT THE TAKE-OFF

  The present invention relates to an aircraft instrument panel, and more particularly to an instrument panel intended to control the pitch speed of said aircraft during take-off and to warn the pilot when this pitch speed deviates from a determined value during the phase of

rotation of takeoff.

  During the take-off rotation, the pilot rotates the aircraft (ie, he takes off the nose of the aircraft from the runway) when the rotational speed of the aircraft, Vr, is reached. . The climb inclination of an airplane is usually 20 from the horizontal. Before the pilot can safely put the airplane in this inclination, the airplane must have taken off sufficiently that its tail does not touch the ground. Wing lift should not occur at the same time as rotation because of the time required to increase airflow around the wings. The taper angle of the tail of a conventional heavy-lift airliner is approximately 10 or 12 when the suspension of the main landing gear of the main landing gear is relaxed, the landing gear being free of weight of the plane during the rotation. With a longer plane, these angles will be reduced to about 7 and 8 respectively. Tail touch on the ground may occur if the nose is straightened too fast before the main landing gear has left the ground. Tail touch may also occur once the aircraft has taken off, if the nose is straightened too fast before the aircraft has reached a sufficient height. As a result, the pilot must ensure that he does not rotate the aircraft at too high a pitch speed to prevent a tail feel. Although flight instruments have been proposed previously to provide information to the pilot during the takeoff firing phase, such as those described in US 3,309,923, no instrumentation has so far been able to to provide information warning of a possible touch of

  tail during the very first take-off phase.

  The take-off procedure is particularly stressful for the pilot because the reactors are running at full speed and the fuel tanks of the aircraft are full. The pilot must monitor a lot of instruments on board

  while controlling the reactors and aerodynamic surfaces of the aircraft.

  The present invention aims to overcome these disadvantages by proposing an aircraft instrument panel that can be used to assist the pilot

  during the rotation phase of take-off.

  For this purpose, the invention relates to an instrument panel for aircraft as defined in the preamble, characterized in that it is arranged to provide a signal io representative of the variation of the pitch angle of said aircraft and to determine if the variation of this pitch angle deviates from a safe limit value, and in that it comprises a display device arranged to warn the pilot when the gradient of the pitch angle during the

  take-off rotation deviates from the safe limit value.

  Advantageously, the instrument according to the invention comprises an input for a sensor responsive to the recovery of the front wheel of the aircraft at the

start of the rotation.

  Preferably, the instrument includes a first warning display when the pitching speed is too high and a second warning display when the pitching speed is too low. Advantageously, the warning display comprises symbols which move vertically when the pitch speed deviates from a safety limit value and which remain stationary when the pitch speed is

  equal to a safety limit value.

  In a preferred embodiment, the instrument comprises a processor, at least one comparator, a reference source of a maximum pitch angle gradient and a reference source of a minimum pitch angle gradient. , the processor receiving signals from a pitch angle sensor and deriving a pitch angle gradient signal, the comparator receiving from the reference source outputs, minimum and maximum angle gradients pitch and the signal representative of the pitch angle gradient, and the comparator providing an output for engaging the warning display when the signal representative of the pitch angle gradient exceeds the maximum gradient of the pitch angle. pitching or falls below the minimum gradient

the pitch angle.

  The display may be triggered after a predetermined time when the main landing gear has left the ground or when the airplane has reached

  predetermined height above the ground.

  The instrument panel may also include a warning display during the descent phase if the pitch angle of the aircraft exceeds a safety limit value and a display to provide the pilot with information.

  information on lateral guidance.

  The present invention and its advantages will become more apparent in the

  following description of an exemplary embodiment, with reference to the drawings

  appended in which: - Figure 1 shows schematically the position of the instrument panel according to the present invention and the various sensors in an aircraft; FIG. 2 is a schematic diagram of the instrument panel according to the present invention; FIGS. 3A to 3C show different images displayed by the instrument according to the present invention, and

  - Figures 4 to 7 show other images that can be displayed.

  With reference to FIGS. 1 and 2, the on-board instrument according to the present invention comprises an electronic box 1 connected to a display unit 2 by a cable 3. The display unit 2 is mounted in the instrument panel the cockpit of the aircraft so that it is in the peripheral field of vision of the pilot. Case 1 can be mounted anywhere

  o in the airplane or inside the unit containing the display device.

  The instrument panel receives inputs from a landing gear contact 4 and a landing contact 5 of the main landing gear. These contacts 4 and 5 provide outputs to indicate whether the nose gear or main gear is touching or touching the ground. The instrument panel also receives an output 0 from a pitch angle sensor 6. This sensor 6 can be housed inside the control unit 1, or it can be in the form of a separate sensor located outside said housing. According to another alternative, the pitch angle detection function can be performed by a sensor

  pitch angle existing, used for other purposes.

  The control unit 1 comprises a processor 40, which receives the output of the pitch angle sensor 6 and from which derives an output δ representative of the gradient of the pitch angle. According to another alternative, the pitch speed can be input directly from a gyroscopic angle variation sensor. Preferably, the processor 40 also performs a function of averaging to reduce the effect of piloting oscillations and other minor disturbances in the pitch angle signal. The output of processor 40 is

  respectively connected to one of the inputs of two comparators 41 and 42.

  The comparator 41 has its other input connected to a reference source 43, which determines a maximum value of the pitch angle gradient (Oma.) The other comparator 42 has its other input connected to a reference source 44, which determines a minimum value of the pitch angle gradient Omin The outputs of the two comparators 41 and 42 are connected to a display control unit 50. This display control unit 50 also receives the outputs of the laying contact 4 of the nose gear and the main landing gear contact 5. It is also connected to the display unit 2

  by means of the cable 3 and provides the output of the electronic box 1.

  The display unit 2 is rectangular in shape and has a front face or screen 20 composed of a matrix table of liquid crystal display elements 21, or other electrically excited display elements, such as

electroluminescent diodes.

  When the aircraft begins to roll on the ground, both the nose gear and the main gear are in contact with the ground and the sensors 4 and 5 provide signals to the flight instrument 1. During this part of the take-off procedure, the on-board instrument 1 maintains the display unit

  off so that the driver is not disturbed.

  When the pilot pulls on the broomstick to straighten the nose of the aircraft and start the rotation phase of the takeoff, the nosewheel begins to leave the ground and the landing pose 4 of the nosewheel changes its output. This causes the instrument panel 1 to turn on the display unit 2. While the pilot maintains the pitch speed of the aircraft within safe limits, the display control 50 displays on the screen 20 an image as shown in Figure 3B. This image consists of a number of dark horizontal bars 22 (three bars are shown in Figure 3B) crossing the screen and separated by clear spaces 23. It remains stationary as the aircraft is maintained within the safety limits of pitch speed, ie less than max. and greater than em. The pilot will then have the display, when turned on, in his peripheral field of vision, so that he will be notified that the nose gear has left the runway. During the rotation, the pilot receives, in his peripheral field of vision, guidance from the display while looking forward through the windshield of the cockpit, and without having to fix his gaze on

The display.

  When the main gear of the plane leaves the track, the sensor 6 modifies its output. This causes the processor 40 to trigger a delay and, after a predetermined time and sufficient for the aircraft to have reached a height at which there is no longer a risk of having a tail feel (usually about 5 seconds ) has elapsed, the instrument panel I triggers the display 2, which is then no longer necessary. Alternatively, the instrument panel can be connected to receive an output of the radar altimeter 7 of the aircraft, instead of the landing contact 5 of the main gear. In this case, the display unit 2 will be triggered as soon as the aircraft has reached a safety height at which there is no longer a risk of having a tail feel. However, if the pilot pulls on the joystick too quickly and causes an excessively high pitching speed and is sufficient for there to be a risk of touching the tail, the input on the comparator 41 will exceed the reference value OmL of the source 43. The comparator 41 will then change its output to the display control unit 50 so that the control unit moves the bars 22 downward, giving the appearance of a continuous stream of bars moving towards the bottom. The speed of movement of the bars is proportional to the difference between the actual pitch speed of the aircraft and the maximum safe pitch speed. This display warning movement easily appears in the driver's peripheral field of view without having to look directly at the display. As a result, the pilot can immediately make a correction without having to turn his head or change his visual focus. The pilot will note that his correction maneuver produces a slower movement of the bars until the aircraft is below the safety limit of the pitch speed, when the image on the display screen becomes at

new stationary.

  If the pilot has not been sufficiently cautious and has not requested a sufficiently high pitch speed, there is a risk that the aircraft will not provide adequate thrust fast enough and track. When the pitch speed is too low, the input that the processor 40 provides to the comparator 42 falls below that of the reference source 43. This causes the comparator 42 to change its output which, in turn, causes the display control unit 50 moves the bars on the image represented on the screen upwardly at a speed proportional to the difference between the actual pitching speed of the apparatus and the minimum pitch pitch Omin . This warns the pilot that he must increase

the pitching speed.

  The present invention allows the pilot to be notified when the pitch speed of the aircraft is out of the safe limits, without having to present him with information that would bother him when they are not needed. The instrument panel may also include an audible alarm, which is triggered when the visual alarm has not caused a corrective response

  from the pilot in a predetermined time.

  The image represented on the display can take many other forms, such as those, for example, represented by FIGS. 4 to 7. In FIG. 4B, the safety pitching speed is represented by a line

  horizontal, continuous extending at mid-height, through the display.

  When the pitch speed is too high, the central part of the line is moved downwards, as shown in FIG. 4A, and when the pitching speed is too low, the central part of the line is moved upwards, as shown in FIG. 4C. In the representation of the display illustrated in Fig. 5, the correct pitch speed produces a white screen, as shown in Fig. 5B, while a too fast pitching speed produces a downward-pointing arrow, such as 5A, and a slow pitching speed produces an upwardly directed arrow as shown in FIG. 5C. The representation of the display can be arranged to change color, as shown in FIG. 6. When the pitch speed is within a safety zone, the image represented is a uniformly green screen, such as 6B, when the pitch speed is too high, the display changes to a red color and a text, such as "FAST" appears on the display, as shown in Figure 6A, and when the speed pitch is too low, the display changes to an orange color and a text, such as "SLOW" is displayed. The format of the display of Figure 6 can be combined with a moving image so that the pilot's attention is drawn with

more strength on the display.

  The instrument panel according to the present invention can also be used to prevent a tail feel during landing due to an excessive pitch angle during the descent phase. The risk of a tail-touch during landing depends only on the inclination, rather than the pitch speed, so the processor does not calculate

  not the gradient of the pitch angle during this phase.

  In the display represented by FIGS. 7A to 7C, the upper part of the display screen 70 shows a representation of the display of the same kind as that of FIG. 6. The lower part of the screen 71 is occupied. by a lateral guidance display. The side guidance display indicates to the pilot if the aircraft is deviating from the center line of the track. It is formed by inclined bands that remain stationary when the unit is properly aligned with the track. When the heading of the aircraft deviates to the right or to the left of the center line, the bands move across the width of the display to the right or left depending on and to a degree depending on the value of the deviation . Since the instrument instrument of the present invention, which warns of a tail feel, is used only during the take-off rotation phase, or during take-off and landing, it is possible to use the display at other points. ends at other times. For example, it can be used to display a warning about an anti-collision action to be performed when there is a risk of collision in the air, as described in GB 2 223 924. It can also be used to display air traffic control instructions, as described

in GB 2 250 494.

  The present invention is not limited to the embodiment described but

  extends to any obvious modification and variation for a person skilled in the art.

Claims (9)

claims   A flight instrument intended to control the pitch speed of an aircraft during take-off, characterized in that it is arranged to provide a signal representative of the variation of the pitch angle of said aircraft and to determine if the variation of this pitch angle deviates from a safety limit value, and in that it comprises a display device (2) arranged to warn the pilot when the gradient of the pitch angle during the phase Takeoff rotation deviates from the safety limit value 2. Instrument instrument according to claim 1, characterized in that it comprises an input for a sensor (6) sensitive to the recovery of the wheel   before the plane at the beginning of the rotation.   3. Instrument instrument according to claim 1 or 2, characterized in that it comprises a first warning display when the pitch speed is too high and a second warning display when the speed of pitching is too weak.   Instrument panel according to one of the preceding claims, characterized   in that the warning display comprises symbols (22, 23) which move vertically when the pitch speed deviates from a safe limit value and which remain stationary when the pitch speed is   equal to a safety limit value.   Instrument panel according to one of the preceding claims, characterized   in that it comprises a processor (40), a comparator (41, 42), a reference source (43) of a maximum gradient of the pitch angle and a reference source (44) of a gradient pitch angle, in that the processor (40) receives signals from a pitch angle sensor (6) and derives a pitch pitch gradient signal, in that the comparator (41, 42) receives, from the reference source outputs (44, 43), minimum and maximum pitch angle gradients and the signal representative of the pitch angle gradient, and that the comparator ( 41, 42) provides an output for engaging the warning display when the signal representative of the pitch angle gradient exceeds the maximum gradient of the pitch angle or falls below the minimum gradient the pitch angle.   Instrument panel according to one of the claims   preceding, characterized in that it triggers the display after a time   predetermined when the main landing gear has left the ground.   7. Instrument panel according to any one of the claims   preceding, characterized in that it triggers the display when the aircraft has   It reaches a predetermined height above the ground.   8. Instrumentation according to any one of the claims   preceding, characterized in that it comprises a warning display during the descent phase if the pitch angle of the aircraft exceeds one safety limit value.   9. Instrumentation according to any one of the claims   preceding, characterized in that it comprises a display for providing the   driver information on lateral guidance.