RU2267142C2 - Device for estimation of landing visibility at different altitides of clouds and weather conditions (landing visibility estimation board) - Google Patents

Abstract

FIELD: meteorological instrumentation engineering; landing of combat aircraft at day time.

SUBSTANCE: proposed device is made in form of board with immovable circles and circle-disk revolving between them. Circular tables made on immovable circles on face and rear sides of board are used for estimation of landing visibility for different altitudes of clouds and meteorological visibility ranges at ground. Circles have three ports each for reading-off initial and intermediate information applied on disk-circle. Each side of disk-circle has three circular scales containing information pertaining to altitude of clouds measured by light radar, altitude of clouds defined more accurately at correction for aircraft speed and maximum landing visibility. Information of each scale coincides with center of respective port in respective immovable circle. Besides that, device is provided with two transparent pointers-rules revolving relative to center of immovable circles and tables applied on these circles. Rules may be set on columns of tables, thus providing for correct reading-out of landing visibility.

EFFECT: enhanced efficiency (estimation time 8-10 s) and accuracy of estimation of landing visibility.

10 dwg

Description

The present invention relates to the field of meteorological instrumentation and can be used to predict landing visibility in the daytime with meteorological support for flights and flights of multi-purpose combat maneuverable aircraft.

The idea of creating various computing devices, consisting of one or more moving parts, which allows to obtain the necessary information with a sufficient degree of accuracy in a limited time and thereby increase operational efficiency, is not new.

The well-known slide rule [1], which until recently was the main tool in engineering calculations.

Known navigation devices, consisting of several interacting parts, with which you can quickly and accurately determine the location of aircraft and ships. So, for example, the navigation counting line NL-10 (NL-10M) is intended to perform the necessary calculations for aircraft navigation [2].

To process spherical pilot observations, the A-39 logarithmic circle is sometimes used, proposed by A.E. Shchekin [3], which consists of a fixed disk, a moving circle, and an index ruler. However, the processing of spherical observations using the circle of P. A. Molchanov (A-30 tablet), which consists of a wooden or metal base with a nomogram glued on it, a movable celluloid disk rotating near its center, and a mobile celluloid ruler [3 , ..., 6].

When receiving signals from the Meteor (or "NOAA") space system, the graphic method for calculating target designations using a special tablet [7] is used, on the base of which a map of the Northern or Southern Hemisphere is glued with a tracking diagram plotted on it relative to the receiving point, and a rotating celluloid a circle with the projection of the orbit of one of the orbits of the satellite on the Earth's surface indicated on it. A slightly modified large target designation tablet is used in the Voronezh VAII when conducting classes in the discipline "Space meteorology" [8]. It allows you to show the actual rotation of the Earth relative to satellite orbits, which increases the visibility in training.

Another typical example of a device consisting of several moving parts (movable scales) is a photo exposure meter [9], which is designed to select and set the required exposure depending on the illumination of the subject and the photosensitivity of the photo material.

Examples of the use of computing devices, such as those described above, can be given further, referring to other areas of knowledge, including a purely military field. For example, devices are known with the help of which the quantitative characteristics of the damaging factors of weapons of mass destruction are quickly and accurately calculated. These devices have neither electrical nor electronic circuits, which ensures their high reliability in combat conditions.

In order to find out information about the possible existence of a device or any device designed to assess landing visibility, a patent search was carried out, starting from 1950 and to 2002, in the following countries: USA, UK, Germany, Germany, USSR, RF It was found that work on the assessment and modeling of slant (landing) visibility was carried out in the USSR and to this day continues in Russia [10, ..., 14]. No information was found on the existence of a device for assessing landing visibility.

It should be noted that during the patent search some materials of foreign origin were found that had a pronounced advertising character, in which, in particular, it was alleged that the captain of the Boeing 737 aircraft during flight on the landing line and the absence or restriction of visibility at aerodromes equipped with blind landing systems ("automated landing"), it is generally forbidden to fly the aircraft until the runway is touched, after which it is necessary to turn on the braking system. Commenting on the foregoing, indirectly asserting that there are no problems with landing visibility in the United States, apparently, it should be critical to the "prohibition of control" in difficult meteorological conditions. Difficult weather conditions are not only fog or dense haze. It is easy to guess what the loss of piloting skills in case of failure of the automatic stabilization system during landing in intense convective phenomena, when the pilots have to “manually” start damping alternating moments of pitch, roll and yaw, even when visibility is limited by rainfall, can lead to it.

Currently, in Russia, all documents defining the rules of flights and flights are being processed and brought into line with international rules [15, ..., 18]. However, until the appearance of official documents regulating flight work, the Flight Operations Manual (NPP-85), and, consequently, a number of other instructions and instructions, remains in force [17, 18]. According to NPP-85, landing visibility is determined by the landing manager when the aircraft enters the descent glide path according to the report of the pilot (crew commander):

"I see the strip!"

Closest to the claimed device is the "Nomographic device" [19], which is a nomogram of aligned points with parallel scales rolled up in a circle. It consists of several rotating limbs and a central disk with scales applied to them, overlapped by a common lid with a sector cut and a radial sight line. The device is designed to solve tactical aviation and marine trigonometric tasks with several variables.

The present claimed device is two interconnected nomograms with "parallel" movable and fixed scales, also folded into a circle. Instead of a sector cut-out, the device has on its front and back sides three round "windows" for reading information, and instead of a radial sighting line, a radial transparent arrow-ruler designed to fix the final result.

This work is the logical conclusion of a long-term comprehensive study on the assessment of landing visual range. Earlier on this topic in the central press, for example, in [6, 20, 21], as well as in university literature (the earliest - [22]) a part of the studies was published, some proposals were presented that facilitate the guidance and flight management group a priori assessment of visibility the beginning of the runway from an aircraft with different cloud heights and horizontal visibility

L _r = 2, ..., 8 km. In particular, in [6] on p. 288, 289 the author’s nomogram for landing visibility assessment is used, which is still used in the practice of work of meteorological aviation units of the Armed Forces. However, due to the lack of flight experiment data, an area with visibility less than 2 km remained unexplored. visibility in dense haze and fog, or in precipitation, worsening horizontal visibility to the specified values. Practice has shown that this drawback allows to a certain extent to compensate for the diagram for determining the inclined visibility range given in [23] on p.573, 574. Here, the value of the inclined visibility is determined by the initial values of horizontal meteorological visibility in the surface layer (usually at a height equal to 5 m, i.e. the height of the plane’s alignment) and the height of the base of the clouds of the lower tier, divided into 5 gradations. Comparison of this diagram [23] with the nomogram [6, 20] showed fairly identical results for estimating the inclined (landing) visibility for all gradations of cloud height and visibility near the earth from 2 to 3 km. Therefore, an attempt was made to use the graphs [23] for an analytical description of the unexplored area, taking into account the corrections [20] for weather phenomena. Only after that, the work on the topic of landing visibility acquired in a certain sense a finished look.

It is well known that using a nomogram (in this case, 8 separate schedules grouped together) requires certain skills and special knowledge. In addition, subjective error in reading information is not ruled out. Therefore, these nomograms [6, 20, ..., 23] can be intended more for a weather engineer than for flight personnel. To make them accessible to pilots and navigators, as well as to increase the efficiency in the work of meteorological support, we need a radically different, simpler form of representing the interrelations of random variables, which does not allow their double interpretation. In other words, instead of the usual prognostic interval for practice, a strictly unambiguous interpretation of the quantitative characteristics of intermediate and final meteorological values is required. For this, as in [19], first of all, “parallel” tables were constructed that easily “fold” into a circle. This form of presentation of information allowed us to start implementing the idea of designing a special device for assessing landing visibility.

The technical side of the problem was reduced to the calculation and execution of the current model of a double-sided tablet (Figures 1 and 2), consisting of five components: two fixed sides (Figures 3 and 4), rigidly connected among themselves, with circular tables of final data plotted on them; a moving disk circle (Figures 5 and 6), rotating between them, with the circular scales of the source and intermediate information plotted on it on both sides; two transparent line arrows (dashed lines in Figures 1 and 2) rotating around the center of symmetry of the circular tables on the front (Figure 1) and back (Figure 2) sides of the tablet. In this case, the center of rotation of the circle-disk has its axis of rotation O ', which does not coincide with the single axis of rotation O of the arrow-rulers.

A diagram of the components of the model is shown in Figure 7. Material for the manufacture of celluloid, cardboard, paper, glue, connecting fasteners. Two transparent celluloid arrows-rulers 1 rotate around the center of symmetry O of two fixed sides 2, and a movable circle-disk 3 - about their axis of symmetry O 'between the fixed sides 2.

When working with a tablet, only one of its sides is used. The choice of side of the tablet is determined by the value of horizontal visibility at the ground. Regardless of the weather phenomenon, with actual runway visibility greater than or equal to 2 km, the front side of the tablet is used (Figure 1), which reflects the estimated landing visibility by OA Zubkov’s nomogram [20]. To work with this side, a circular digitization of three circle-disk scales is shown, shown in Figure 5. When visibility on the runway is less than 2 km, the reverse side of the tablet is used (Figure 2), which reflects the sloping visibility rating according to the diagram of A. S. Zverev [23]. Three circular dials of the reverse side are plotted on the other side of the same disk circle (Figure 6).

When you turn the circle-disk on either side of the device in three special holes called "windows" (windows 1, 2, 3), a numerical value of three meteorological values will appear immediately. The windows have a circle shape with a diameter of about 10-12 mm and are cut out on the fixed parts of the tablet. They are located on the free sector of the field of circular tables and are indicated in the field of tables by the type of information that appears in them due to the rotation of the circle-disk relative to O '(Figures 1, ..., 4): the height of the clouds "according to the optical fiber" N _SL ( m) (window 1); cloud height "by plane" N _CAM (m) (window 2); data on theoretical (maximum possible) landing visibility L _{P max} (window 3). The location of the windows is directly related to the dials printed on both sides of the disk circle. Each window is located strictly above the "own" scale. Therefore, each value of the height H _SL (window 1) corresponds to one (and only one!) Value of the height H _CAM (window 2) and the value L _{P max} (window 3). For example (Figure 1), the height H _SL = 250 m (window 1) corresponds to the height H _CAM = 233 m (window 2) and the maximum possible visibility L _{P max} = 5.4 km (window 3). Another example (Figure 2), the height H _SL = 120 m (window 1) corresponds to the height H _CAM = 96 m (window 2) and the theoretical visibility L _{P max} = 2.6 km. Any other combination of information (Figures 5 and 6) will simply be covered by the front (back) side of the landing visibility assessment tablet (OPV tablet). The information turns out to be consistent, linked to each other, it is impossible to see other values of meteorological values. For three other variables to appear, you need to rotate the circle-disk.

In Figures 1, ..., 4.7, a horizontal technological slice made from above on both fixed parts of the tablet is clearly visible. It serves to organize the rotation of the disk-circle relative to the axis O '(Figures 1, ..., 4) in order to set the initial information in window 1 and automatically read the intermediate information in windows 2 and 3. Therefore, the disk-disk located between two fixed sides should slightly protrude above the technological slice (Figures 1 and 2). The axis O 'of rotation of the disk-disk is shifted by a certain distance from a single center of symmetry O of circular tables plotted on the front and back sides of the device (Figures 1, ..., 4.7). This distance, determined empirically, is commensurate with half the radius of the circular tables. Structurally, the rotation axis of the disk-circle from the center of symmetry of the circular tables can be produced in any direction; from an aesthetic point of view - strictly up (360 °) to the center of the technological cut. It should be noted that the displacement of the axis of rotation O ′ of the disk-circle is also determined by the diameter of the first (external) circular scale applied to the disk-circle (Figures 5 and 6). This scale should not protrude above the technological slice.

Figures 1, ..., 4 show that information about landing visibility printed on the front and back sides of the device is distributed in a circle with the center O coinciding with the axis of rotation of the transparent arrow-rulers. Rows of tables correspond to weather phenomena indicated by the symbols adopted in meteorology. The columns of the tables correspond to the horizontal visibility values on the runway. The table of the front side of the OPV tablet (Figure 3) is divided into six sectors, any of which illustrates the results of calculating landing visibility using one of the six equations proposed in [20]. The back side table (Figures 2 and 4) is divided into four sectors that display the results of calculating landing visibility from the four lower curves of the diagram [23] in the horizontal visibility range L _g = 200, ..., 1800 m. The circular tables have the standard meteorological standard color: haze, fog - yellow; rain, snow, drizzle - green.

Two identical transparent arrow-rulers (Figures 1 and 2 (dotted line), 7) rotate independently of the moving circle-disk near the center О of both circular tables. The length of the ruler arrows is equivalent to their outer radius, the width is 15 mm. Arrow-rulers were cut from white transparent celluloid. Their purpose is to fix the column of the circular table with the desired landing visibility L _P depending on the weather, horizontal visibility L _g on the runway and the height of the clouds "converted to the plane" N _CAM (window 2). The last predictor takes into account the features of the cockpit glazing, runway detection height, speed on the landing line, etc. The use of rulers eliminates a possible error in reading the final information under stressful loads on the body of the weather foreman on duty during the flight support period. The ruler arrow overrides the entire column containing the information sought.

The tablet model, structurally consisting of the parts shown in Figure 7, was made in the amount of three copies. In order to find out its operability and practical suitability, the device was tested during the year in the educational process of the Hydrometeorological Faculty of the Voronezh Aviation Institute, as well as while providing flights with the weather services of the Krasnodar Aviation Institute (now Krasnodar VVAUL) and military unit 35451 (Chita). This made it possible to identify a number of shortcomings and begin to create a more perfect model - a stand-tablet for assessing landing visibility. In the general opinion, such shortcomings were:

- fuzzy matching of three movable dials with windows 1, 2 and 3, which in some cases leads to "hiding" information;

- insufficient structural rigidity, indirectly affecting the correct reading of data;

- lack of a protective coating (film) that protects the device from contamination during repeated use.

The first drawback was eliminated by the location on the moving disk-disk of two dial scales with three-digit cloud heights (Figures 5 and 6), determined by the light-locator (H _SL ) and by plane (H _CAM ) along the two circles of the largest diameter, and with two-digit theoretical values landing visibility (L _{P max} ) - along the inner circumference of the smallest diameter. Comparing Figure 1 with Figure 9 and Figure 2 with Figure 10, you can see that the change led to the replacement of the information in windows 2 and 3. In a more advanced version of the tablet (figures 8, ..., 10) in window 2 (figures 9 and 10) instead of data on the height of N _CAM (Figures 1 and 2), information is given on the visibility L _{P max} , and in window 3 instead of visibility L _{P max} is the height H _CAM .

Two other drawbacks were eliminated by using three plexiglass sheets and two 500 × 500 mm plastic sheets in the design, tightened with six M: 3 screws, two of which are the axis of rotation of the movable circle and transparent ruler arrows. Figures 7 and 8 are made in order to compare the design of the OPV tablet model (Figures 1 and 2) and the OPV tablet stand (Figures 9 and 10). The diagram (Figure 8) shows that the tablet stand consists of eight parts: two ruler arrows 1 (for the front and back sides) made of (yellow 2 mm) plexiglass and designed to fix the column of horizontal visibility values on the runway depending from the height of the clouds, determined by the plane N _CAM ; two transparent (2 mm) sheets of Plexiglass 2 (for the front and back side of the tablet that can be dirty; two thin sheets of plastic 3 (for the front and back sides), which are the basis for two sheets of Whatman paper with circular tables; the central sheet of hard material 4 (in in this case - 3 mm plexiglass), providing free rotation of the disk-disk 5, made of thinner (2 mm) plexiglass with two-sided information on the cloud height H _SL and H _CAM and visibility L _{P max} .

The technical solution shown in Figures 8, ..., 10 does not change the essence of the device (Figures 1, ..., 7), but only is its improvement. Therefore, the principle of working with this stand-tablet, made mainly for educational purposes, is absolutely identical to working with its original version.

In addition to the above disadvantages, other ones were mentioned that either do not require explanation or go beyond the description of the device. For example, during the operation of the tablet in military unit 35451, the reverse side ruler broke, and in Krasnodar VAI, the axis of rotation of the circle-disk became loose from repeated use. Attention was drawn to some issues related to landing visibility theory: the tablet "underestimates" landing visibility at night; the tablet does not take into account cases of higher landing visibility than horizontal visibility on the runway during surface inversion, which greatly impairs visibility at the height of the plane’s alignment.

The following is an algorithm for working with an OPV tablet using the examples of Figures 1 and 2. The choice of an example variant — by model or by tablet stand — is purely conditional in nature, without affecting the procedure for determining the predictive value of landing visibility L _P.

Suppose that for some atmospheric phenomenon (haze, fog, rain, snow, drizzle) that worsens visibility, the weather conditions correspond to the height of the clouds "on the instrument" N _SL = 250 m and the horizontal range of visibility on the runway (near the ground) L _g = 5 5 km. It should be noted that current information about the height of H _SL and the visibility of L _g at any time of the day is available in the weather division. The algorithm of the meteorological engineer (pilot, navigator) on the tablet is as follows:

a) it follows from the weather conditions that the horizontal range of visibility at the ground is more than 2 km, which requires contacting the front side of the device (according to O.A. Zubkov);

b) by turning a disk-circle (Figure 3) by its part protruding above the upper technological section (Figure 1) in window 1, the initial condition for the cloud height of 250 m, measured by the light-beam, is established, which immediately leads to the reading of the cloud height in the window 2 " by plane "233 m, and in window 3 - the maximum possible (theoretical) landing visibility L _{P max} equal to 5.4 km;

c) if the height of the clouds "by plane" is 233 m, then this necessitates the use of a circular table (Figure 1) in the sector 200≤N _CAM ≤250 m;

d) taking into account the initial condition of horizontal visibility equal to 5.5 km, you should rotate (figure 1 - dashed line) the transparent arrow-ruler on the border of adjacent columns of the table corresponding to horizontal visibility of 5 and 6 km, and obtain (interpolate) the final a priori value of the landing visibility

e) record the result of the assessment of landing visibility in the workbook of the meteorologist on duty (on duty at the airfield): with haze - 2.8 km; in the rain - 2.6 km; with snow - 2.35 km; drizzle - 2.25 km.

From a comparison of these data with the value of the maximum possible landing visibility L _{P max} = 5.4 km, it follows that meteorological phenomena worsen landing visibility by about half (by 50%).

Forecast: under weather conditions of 250 m × 5.5 km and the corresponding phenomena, landing visibility will not exceed 3 km, or in another way - 2, ..., 3 km.

Suppose that for some (another example) atmospheric phenomenon (haze, fog, rain, snow, drizzle) that worsens visibility, weather conditions correspond to the height of the clouds along the radar N _SL = 120 m and the horizontal range of visibility on the runway L _g = 1600 m. The landing visibility assessment algorithm is as follows (Figure 2):

a) if the visibility at the ground L _{g is} less than 2 km, then this requires the use of the back of the tablet (according to A.S. Zverev);

b) by turning the disk-disk (Figure 4) for its part protruding above the upper technological section (Figure 2) in window 1, the initial condition is established for the height of the lower boundary of the clouds 120 m, which leads to the reading in the window 2 of the cloud height "by plane" m, and in window 3 - the maximum possible landing visibility under these conditions, equal to 2.6 km;

c) if the height of the clouds "by plane" is 96 m, then this necessitates an appeal to the sector of circular tables N _CAM <100 m (Figure 2);

d) when visibility L _g = 1600 m, you should rotate (Figure 2 - dotted line) a transparent arrow-ruler on the column corresponding to this visibility in sector H _CAM <100 m;

d) get the final version of landing visibility: with haze - 400 m; in the rain - 360 m; in the snow - 340 m; with drizzle - 320 m.

A comparison of these values with the value of the theoretically possible visibility L _{P max} = 2.6 km shows that in a particular case, precipitation and dense haze worsen landing visibility by 85-88%, i.e. almost 7-8 times. The last example illustrates very well the effect of a high landing speed of a fighter on the pilot's identification of the start of a runway.

Forecast: under weather conditions of 120 m × 1600 m and the corresponding weather phenomena, landing visibility does not exceed 300-400 m.

The time for assessing landing visibility in both examples is 8-10 seconds.

In conclusion, we sincerely thank Peter Vasilyevich Shelyganov (Lipetsk, military unit 62632) - the pilot of the MiG-29 aircraft, who died tragically in the line of duty. Joint discussions and real data on visibility in weather phenomena during landings and imitations of landings made by him personally made significant progress on this topic. This recognizes his full right of co-authorship of the claimed device.

Sources of information

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Claims (1)

A device for assessing landing visibility at different cloud heights and weather phenomena, made in the form of a tablet and containing fixed circles and a circle-disk rotating between them with circular scales applied to it, information from each of which is removed in the corresponding window of the fixed circle, characterized in that fixed circles on the front and back sides of the tablet are marked with circular landing visibility tables for different ranges of cloud heights and meteorological visibility ranges near the ground, and in the indicated three windows for reading the source and intermediate information printed on the disk-circle are made, and on each side of the disk-circle there are three circular scales with information about the cloud height measured by radar, about the cloud height adjusted for airplane speed and about the maximum possible landing visibility so that the information of each scale coincides with the center of the corresponding window in the corresponding fixed circle, while the device is equipped with two transparent arrows-rulers, rotating from relative to the center of the fixed circles and the indicated circular tables plotted on these circles, with the possibility of installing on one or another column of the circular table.

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