Communications: electrical – Aircraft alarm or indicating systems – Nonairplane
Reexamination Certificate
1999-09-22
2001-07-03
Lee, Benjamin C. (Department: 2736)
Communications: electrical
Aircraft alarm or indicating systems
Nonairplane
C340S971000, C340S972000, C340S973000, C340S975000, C701S016000
Reexamination Certificate
active
06255965
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for aiding the piloting of an aircraft, especially a rotary-wing aircraft and in particular a helicopter.
More precisely, it relates to a device making it possible to present information cues to a pilot of the aircraft, which are capable of providing the latter with indications regarding the exact position of said aircraft with respect to the surrounding space, especially in poor visibility, or even in the complete absence of visibility. Such cues are generally very useful, or even indispensable, when approaching a landing strip.
2. Description of Related Art
On aeroplanes, especially civil transport aeroplanes, a device for presenting cues of this type is known, and is associated with a guidance beam or axis (for example of the “ILS” type) transmitted from the ground in proximity to a landing strip and which is intended to guide the aeroplane during the approach to the strip, with a view to landing.
To this end, the known device provides the pilot(s) with two cues presented on a display screen, namely:
a first cue (“LOC”) comprising an arrow which the pilot must orient in terms of heading on the guidance axis and a deviation bar, whose lateral displacement on the screen with respect to the arrow is representative of the offset between the guidance beam and the position of the aircraft; and
a second cue (“GLIDE”) which indicates the relative vertical position between said guidance axis and the position of the aircraft.
These cues relate to values which are proportional to the angle between said guidance axis and the line of aim of the point at which the aircraft expects to touch down.
Such a known device for presenting cues is well suited to an approach made in a straight manner, with a fixed and relatively gentle slope, for example 3°, as is generally the case for an aeroplane.
However, when the approach has to be made according to a preset path which exhibits several successive segments exhibiting different headings and slopes, as well as relatively large values of slope of up to 15°, as may be the case for a helicopter, the aforesaid cues are not appropriate and are moreover inadequate.
This is because a cue in angular form obliges the pilot to pass through a particular point in space. Now, such a constraint is not useful in respect of the various points of transition of a path having a plurality of segments, with the exception of the last segment terminating in the landing strip.
Moreover:
an approach at gentle slope, around 3°, is not well suited to the deployment capabilities of helicopters; and
helicopters must be able to land on unprepared zones which are not furnished with guidance beams.
Consequently, the known and aforesaid device is not satisfactory for guidance along complex preset paths.
The document FR-2 666 428 describes a process for displaying pilot-aid symbols on a screen aboard an aircraft. This known document teaches in particular the displaying, according to a three-dimensional representation, of the approach segments situated on the path which the aeroplane must travel. To this end, the current segment of travel, as well as the next segment, are displayed respectively according to two parallelepipeds, in perspective.
Furthermore, the document FR-2 752 051 discloses a device for assisting the guidance of a vehicle over a path. This known device comprises means for determining the slope and the heading of a flight path which the vehicle can take in order to join up with a preset path and means for displaying a guidance window, into which must be brought and wherein must be maintained a symbol representing the speed vector of the aeroplane, during the guidance of the aeroplane. This guidance window is centered on a preset point which represents the direction of guidance to be followed by the aircraft, in terms of heading and slope. The coordinates of this preset point are defined by the point of intersection between a sphere (of fixed radius) centered on the position of the aeroplane and the preset path.
However, the pilot has no information regarding the discrepancies of slope and of heading between the preset and flight paths, and this may be very detrimental in certain flight conditions.
SUMMARY OF THE INVENTION
The object of the present invention is to remedy these drawbacks. It relates to a pilot-aid device capable of presenting to a pilot of an aircraft, and especially of a helicopter, cues enabling him to carry out, in a simple and efficient manner, piloting along a complex preset path, exhibiting for example a plurality of segments of different slopes and headings.
To this end, according to the invention, the device for aiding the piloting of an aircraft, especially a rotary-wing aircraft, in particular a helicopter, comprises:
first means for determining the slope and the heading of a flight path which said aircraft can take in order to join up with a preset path; and
second means for presenting, on a display screen, a second characteristic sign, whose position on said display screen is representative both of the slope and of the heading of said flight path,
is noteworthy in that said first means moreover determine the slope and the heading of the preset path of the aircraft, in that said second means moreover present, simultaneously with said second characteristic sign, a first characteristic sign, whose position on said display screen is representative both of the slope and of the heading of said preset path, and in that said slope and said heading of the flight path are such that the distance between said first and second characteristic signs on said display screen is dependent:
according to a first direction representing the heading, on the distance in a horizontal plane between the position of the aircraft and said preset path; and
according to a second direction representing the slope, on the distance in a vertical plane between the position of the aircraft and said preset path.
Thus, by virtue of the invention, the pilot(s) is (are) presented not with cues in angular form, but with cues representative of distance offsets, specified below, thereby making it possible to remedy the aforesaid drawbacks.
Moreover, by virtue of the invention, cues are also provided which relate to the slope, both of the guidance path and of the preset path, this not being the case for the aforesaid device disclosed by the document FR-2 752 051. These cues provided simultaneously are necessary in particular when various segments of the preset path exhibit arbitrary slopes which may have high values. This is because, when the aircraft is for example situated below the preset path, it is necessary to know the slope of the latter so as to bring about a greater descent slope of the aircraft, so that it can join up with this preset path. Moreover, by virtue of the invention, the discrepancies in heading and in slope between said preset and guidance paths are deduced easily and rapidly by a pilot from the distances between said first and second characteristic signs, along said first and second directions respectively.
Furthermore, the device in accordance with the invention is not bound by a guidance axis and can be used anywhere.
Furthermore, preferably:
the discrepancy in slope p and the discrepancy in heading r between said preset and flight paths satisfy the following relations which depend on the distances dv and dh in meters m respectively in the vertical plane and the horizontal plane between the position of the aircraft (H) and said preset path (T):
if dv>25 m, p is proportional to {square root over (d)}
if dv<25 m, p is proportional to dv/5
if dh>25 m, r is proportional to {square root over (dh)}
if dh<25 m, r is proportional to dh/5; and
when the preset path comprises a plurality of successive segments, the current segment, used to determine the slope and the heading of said preset path, is advantageously the one which is closest to the position of the aircraft.
It will be noted that within the context of the present invention, said display screen can be
Eurocopter
Lee Benjamin C.
Stevens Davis Miller & Mosher LLP
LandOfFree
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