AIRCRAFT TAIL NAVIGATION LIGHT, AIRCRAFT COMPRISING AN AIRCRAFT TAIL NAVIGATION LIGHT, AND METHOD OF OPERATING AN AIRCRAFT TAIL NAVIGATION LIGHT

Abstract

An aircraft tail navigation light comprises: a navigation lighting assembly for emitting a regular navigation light output; and an orientation lighting assembly for emitting an orientation light output. The aircraft tail navigation light is switchable between emitting the regular navigation light output having a navigation light intensity and emitting the orientation light output having an orientation light intensity, with the navigation light intensity being larger than the orientation light intensity

Claims

1. An aircraft tail navigation light, comprising: a navigation lighting assembly for emitting a regular navigation light output; and an orientation lighting assembly for emitting an orientation light output; wherein the aircraft tail navigation light is switchable between emitting the regular navigation light output having a navigation light intensity and emitting the orientation light output having an orientation light intensity; and wherein the navigation light intensity is larger than the orientation light intensity.

2. The aircraft tail navigation light according to claim 1, wherein the navigation light intensity is at least 5 times as large, in particular between 5 times and 50 times as large, further in particular between 5 times and 20 times as large, as the orientation light intensity.

3. The aircraft tail navigation light according to claim 1, wherein the navigation lighting assembly has a navigation light output area and the orientation lighting assembly has an orientation light output area, as seen from a distance from the aircraft tail navigation light, in particular as seen from a distance of between 10 m and 50 m from the aircraft tail navigation light; and wherein the orientation light output area is larger than the navigation light output area.

4. The aircraft tail navigation light according to claim 3, wherein the orientation light output area is at least 100 times as large as the navigation light output area; wherein the orientation light output area is in particular at most 3000 times as large as the navigation light output area; wherein the orientation light output area further in particular is between 100 and 3000 times as large as the navigation light output area.

5. The aircraft tail navigation light according to claim 1, wherein the navigation lighting assembly comprises at least one navigation light source and an optical system, which is arranged over the at least one navigation light source for shaping the regular navigation light output from light emitted by the at least one navigation light source; wherein the optical system in particular comprises a lens for shaping the regular navigation light output.

6. The aircraft tail navigation light according to claim 1, wherein the orientation lighting assembly comprises at least one orientation light source and an orientation light output diluting element, which is arranged over the at least one orientation light source for shaping the orientation light output from light emitted by the at least one orientation light source.

7. The aircraft tail navigation light according to claim 6, wherein the orientation light output diluting element comprises a light sieve, and wherein the light sieve comprises light blocking barrier portions and light passing portions.

8. The aircraft tail navigation light according to claim 7, wherein the light sieve is made of a material that is partly reflective and partly translucent for light emitted by the at least one orientation light source; and/or wherein the light blocking barrier portions of the light sieve are partly reflective and partly translucent for light emitted by the at least one orientation light source.

9. The aircraft tail navigation light according to claim 7, wherein the light passing portions include openings or transparent inserts that allow light emitted by the at least one orientation light source to pass through the light sieve.

10. The aircraft tail navigation light according to claim 7, wherein the light passing portions are arranged in a pattern; wherein a projection of the at least one orientation light source onto said pattern is located at a center portion of the pattern.

11. The aircraft tail navigation light according to claim 10, wherein light passing portions located at a greater distance from the center portion of the pattern are larger than light passing portions arranged closer to the center portion of the pattern.

12. The aircraft tail navigation light according to claim 10, wherein the pattern includes multiple annular arrangements of light passing portions; or wherein the pattern includes a rectangular matrix arrangement of light passing portions, in particular a quadratic matrix arrangement of light passing portions.

13. The aircraft tail navigation light according to claim 6, wherein the orientation light output diluting element, in particular the light sieve thereof, has a light emission surface area of at least 100 mm.sup.2, in particular a light emission surface area of at least 1000 mm.sup.2; and/or wherein the orientation light output diluting element, in particular the light sieve thereof, has an extension of at least 10 mm, in particular an extension of between 30 mm and 70 mm, further in particular an extension of between 40 mm and 60 mm.

14. An aircraft, such as an airplane or a helicopter, comprising the aircraft tail navigation light according to claim 1.

15. A method of operating the aircraft tail navigation light according to claim 1, wherein the method includes selectively operating the aircraft tail navigation light in a regular navigation light mode or in an orientation light mode; wherein, when the aircraft tail navigation light is operated in the regular navigation light mode, the navigation lighting assembly is activated, providing the regular navigation light output, and the orientation lighting assembly is deactivated; and wherein, when the aircraft tail navigation light is operated in the orientation light mode, the navigation lighting assembly is deactivated, and the orientation lighting assembly is activated, providing the orientation light output.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Further exemplary embodiments of the invention are described in the following with respect to the accompanying drawings, wherein:

[0070] FIG. 1 depicts a schematic top view of an aircraft according to an exemplary embodiment of the invention, which is equipped with a variety of exterior aircraft lights;

[0071] FIG. 2 depicts a schematic side view of an aircraft according to an exemplary embodiment of the invention, which is equipped with an aircraft tail navigation light in accordance with an exemplary embodiment of the invention;

[0072] FIG. 3 shows a perspective view of an aircraft tail navigation light according to an exemplary embodiment of the invention;

[0073] FIG. 4 shows a cross-sectional view of the aircraft tail navigation light depicted in FIG. 3, with the cross-sectional plane extending through the orientation lighting assembly;

[0074] FIG. 5 depicts a perspective view of an orientation light output diluting element of an aircraft tail navigation light according to an exemplary embodiment of the invention;

[0075] FIG. 6 depicts a plan view of the orientation light output diluting element depicted in FIG. 5; and

[0076] FIG. 7 depicts a cross-sectional view of the orientation light output diluting element depicted in FIGS. 5 and 6.

DETAILED DESCRIPTION

[0077] FIG. 1 shows a schematic top view of an aircraft 100 according to an exemplary embodiment of the invention. The aircraft 100 is an airplane, comprising a fuselage 130, which houses a cockpit 202 and a passenger cabin 204, and two wings 140a, 140b, extending from the fuselage 130. Two horizontal stabilizers 170a, 170b and a vertical stabilizer 180 extend from a rear portion of the fuselage 130. A respective engine 150a, 150b is mounted to each of the wings 140a, 140b.

[0078] The aircraft 100 depicted in FIG. 1 is equipped with a wide variety of exterior lights. In particular, the aircraft 100 is equipped with three navigation lights 106a-106c, two logo lights 108, two wing scan lights 110, two engine scan lights 112, two runway turn-off lights 114, two cargo loading lights 116, three white strobe anti-collision lights 118a-118c, two red-flashing anti-collision beacon lights 120, a landing light 122, a take-off light 124, and a taxi light 126. It is pointed out that these kinds of lights and their numbers are exemplary only and that the aircraft 100 may be equipped with additional lights that are not shown in FIG. 1.

[0079] A port side navigation light 106a, emitting light having red color, is arranged at the wing tip 142a of the left wing 140a. A starboard navigation light 106b, emitting light having green color, is arranged at the wing tip 142b of the right wing 140b. A tail navigation light 106c, emitting light having white color, is positioned at the tail 160 of the aircraft 100.

[0080] The different colors of the light outputs, as emitted by the different navigation lights 106a-106c, indicate to the aircraft environment if they are looking at the port side, at the starboard side or at the tail side of the aircraft 100. Traditionally, the navigation lights 106a-106c are normally activated during all phases of the flight and in all flight conditions.

[0081] The logo lights 108 are directed to the vertical stabilizer 180 of the aircraft 100 and are provided for illuminating the same, in particular for illuminating the logo commonly provided on the vertical stabilizer 180. The logo lights 108 are normally switched on for the entire duration of the flight during night flights. It is also possible that the logo lights are only used during taxiing on the airport and are normally switched off during the flight.

[0082] The wing scan lights 110 and the engine scan lights 112 are positioned on the left and right sides of the fuselage 130, in front of the roots 144a, 144b of the wings 140a, 140b of the aircraft 100. The wing scan lights 110 and the engine scan lights 112 are normally off during the flight and may be switched on periodically or upon reasonable cause by the pilots or by the aircrew, in order to check the wings 140a, 140b and the engines 150a, 150b of the aircraft 100.

[0083] The runway turn-off lights 114 are positioned in the roots 144a, 144b of the wings 140a, 140b. The runway turn-off lights 114 are directed forwards and are normally switched off during the flight and switched on during taxiing, at least at night.

[0084] The cargo loading lights 116 are positioned on the left and right sides of the fuselage 130, behind the wings 140a, 140b and in front of the tail structure of the aircraft 100. They are normally switched off during the flight of the aircraft 100.

[0085] A white wing strobe anti-collision light 118a-118b is positioned in the left and right wing tip 142a, 142b, respectively. A white tail strobe anti-collision light 118c is positioned at the tail 160 of the aircraft 100. During normal operation of the aircraft 100, the white strobe anti-collision lights 118a-118b emit respective sequences of white light flashes. It is also possible that the white strobe anti-collision lights 118a-118b are only operated during night and in bad weather conditions.

[0086] The red-flashing anti-collision beacon lights 120 are positioned on the top and the bottom of the fuselage 130 of the aircraft 100. They are arranged at the height of the wings in the longitudinal direction of the aircraft 100. While one of the red-flashing anti-collision beacon lights 120 is disposed on the top of the fuselage 130, the other one of the red-flashing anti-collision beacon lights 120 is disposed on the bottom of the fuselage 130 and is therefore shown in phantom in FIG. 1. The red-flashing anti-collision beacon lights 120 are normally switched on during taxiing and during take-off and landing. Their output is perceived as a sequence of red light flashes in a given viewing direction. In alternative configurations, three red-flashing anti-collision beacon lights may be provided alongside or integrated with the white strobe anti-collision lights 118a-118b.

[0087] In the embodiment depicted in FIG. 1, the runway turn-off lights 114 are located in the wings 140a, 140b, in particular in the roots 144a, 144b of the wings 140a, 140b, and the landing light 122, the take-off light 124 and the taxi light 126 are mounted to the front gear 135 of the aircraft 100. The front gear 135 is stored within the fuselage 130 of the aircraft 100 during flight, and it is deployed during landing, taxiing and take off.

[0088] In alternative embodiments, which are not explicitly shown in the figures, the runway turn-off lights 114 may be mounted to the front gear 135 and/or at least one of the landing light 122, the take-off light 124 and the taxi light 126 may be installed in the wings 140a, 140b, in particular in the roots 144a, 144b of the wings 140a, 140b, of the aircraft 100.

[0089] The aircraft 100 may also comprise one or more multi-functional lights, which combine(s) the functionalities of at least two of a landing light, a take-off light, a taxi light, a runway turn-off light, a navigation light, a white strobe anti-collision light, and a red-flashing beacon light.

[0090] Since the landing light 122, the take-off light 124, and the taxi light 126 are arranged on the bottom of the aircraft 100, they are also depicted in phantom in FIG. 1.

[0091] In the exemplary embodiment of FIG. 1, the tail navigation light 106c is an aircraft tail light in accordance with an exemplary embodiment of the invention. It is also possible that a combined aircraft tail light in accordance with an exemplary embodiment of the invention is provided at the tail of the aircraft 100, with the combined aircraft tail light providing the functionalities of the tail navigation light 106c and the tail anti-collision light 118c. Having an aircraft tail light in accordance with an exemplary embodiment of the invention, the aircraft 100 is an aircraft in accordance with an exemplary embodiment of the invention.

[0092] FIG. 2 shows a schematic side view of an aircraft 100 according to an exemplary embodiment of the invention, as it is depicted in FIG. 1. In order to enhance the clarity of the illustration, only the aircraft tail navigation light 106c is depicted at the tail of the aircraft 100 of FIG. 2. The aircraft 100 may comprise at least one additional aircraft tail light, which is not depicted in FIG. 2.

[0093] FIG. 3 shows a perspective view of an aircraft tail navigation light 106c according to an exemplary embodiment of the invention.

[0094] The aircraft tail navigation light 106c comprises a navigation lighting assembly 4 for emitting a regular navigation light output, and an orientation lighting assembly 6 for emitting an orientation light output. The navigation lighting assembly 4 and the orientation lighting assembly 6 are spaced in a transverse direction of the aircraft tail navigation light 106c, i.e. in a transverse direction in the aircraft frame of reference, when the aircraft tail navigation light 106c is mounted to an aircraft.

[0095] In the embodiment depicted in FIG. 3, the navigation lighting assembly 4 is located on a left side/portside of the aircraft tail navigation light 106c, and the orientation lighting assembly 6 is located on a right side/starboard side of the aircraft tail navigation light 106c. This is, however, only an exemplary configuration, and exemplary embodiments of the invention may include different configurations, such as configurations in which the orientation lighting assembly 6 is located on the left side of the navigation lighting assembly 4. In further embodiments, the orientation lighting assembly 6 may be located on top of or below the navigation lighting assembly 4.

[0096] The aircraft tail navigation light 106c further comprises a circuit board 10, extending between the navigation lighting assembly 4 and the orientation lighting assembly 6 and supporting electric circuitry 12.

[0097] The navigation lighting assembly 4, the orientation lighting assembly 6, and the circuit board 10 are located in a common housing 8. The housing 8 comprises a surrounding flange 9, which allows for mounting the housing 8 to the fuselage 130 of an aircraft 100.

[0098] In operation, a light transmissive cover 14 (see FIG. 4), which is not shown in FIG. 3, covers the navigation lighting assembly 4, the orientation lighting assembly 6, and the circuit board 10.

[0099] The orientation lighting assembly 6 comprises at least one orientation light source 62 and an orientation light output diluting element 18. The orientation light output diluting element 18 is arranged over the at least one orientation light source 62 for shaping the orientation light output from light emitted by the at least one orientation light source 62.

[0100] The navigation lighting assembly 4 comprises at least one navigation light source 42 and an optical system 44. The optical system 44 is arranged over the at least one navigation light source 42 for shaping the regular navigation light output from light emitted by the at least one navigation light source 42.

[0101] The optical system 44 may, for example, comprise at least one of a lens, a reflector and a shutter for shaping the regular navigation light output from light emitted by the at least one navigation light source 42. In the exemplary embodiment of FIG. 3, the optical system 44 consists of a single lens.

[0102] The at least one navigation light source 42 and the optical system 44 may be mounted to and supported by the circuit board 10.

[0103] FIG. 4 shows a cross-sectional view of the aircraft tail navigation light 106c depicted in FIG. 3, with the cross-sectional plane extending through the orientation lighting assembly 6. In particular, the cross-sectional plane may extend orthogonal to the circuit board 10 and/or may be a vertical cross-sectional plane in the aircraft frame of reference that is substantially aligned with the longitudinal direction of the aircraft. Accordingly, the rearward direction of the aircraft is towards the right in the drawing plane of FIG. 4.

[0104] The light transmissive cover 14 covers the navigation lighting assembly 4, not shown in FIG. 4, and the orientation lighting assembly 6.

[0105] The orientation lighting assembly 6 comprises at least one orientation light source 62 and an orientation light output diluting element 64, which is arranged over the at least one orientation light source 62 for shaping the orientation light output from light emitted by the at least one orientation light source 62.

[0106] The at least one orientation light source 62 and the orientation light output diluting element 64 may be mounted to and supported by the circuit board 10.

[0107] The at least one navigation light source 42 and the at least one orientation light source 62 may be LEDs, respectively.

[0108] The at least one navigation light source 42 and the at least one orientation light source 62 may have light output areas that do not exceed 2 mm.sup.2, respectively. The light output areas of the at least one navigation light source 42 and the at least one orientation light source 62 may, in particular, not exceed 1 mm.sup.2.

[0109] The at least one navigation light source 42 and the at least one orientation light source 62 may be switchable independently of each other. The tail navigation light 106c may in particular be switchable between a navigation light mode, in which the at least one navigation light source 42 is activated for emitting a navigation light output, and an orientation light mode, in which the at least one navigation light source 42 is deactivated and the at least one orientation light source 62 is activated for emitting an orientation light output. When the tail navigation light 106c is operated in the navigation light mode, the at least one orientation light source 62 is usually deactivated, but it may also be activated.

[0110] The at least one navigation light source 42 and at least one orientation light source 62 may be of identical design. The light sources 42, 62 may, in particular, be of a design of a conventional tail navigation light comprising redundant light sources. This may allow for retrofitting/reconfiguring existing aircraft tail navigation lights, which have redundant navigation lighting functionality, to aircraft tail navigation lights 106c according to exemplary embodiments of the invention, which are selectively operable in a navigation light mode and in an orientation light mode.

[0111] FIG. 5 depicts a perspective view of an orientation light output diluting element 64 of an aircraft tail navigation light according to an exemplary embodiment of the invention. FIG. 6 depicts a plan view of the orientation light output diluting element 64, as depicted in FIG. 5, and FIG. 7 depicts a cross-sectional view of the orientation light output diluting element 64, as depicted in FIGS. 5 and 6.

[0112] The exemplary embodiment of an orientation light output diluting element 64, as depicted in FIGS. 5 to 7, is provided as a light cap, which is rotationally symmetric with respect to an axis A. This orientation light output diluting element 64 may be employed in an aircraft tail navigation light in accordance with an exemplary embodiment of the invention, as for example depicted in FIG. 3 and/or FIG. 4.

[0113] The orientation light output diluting element 64 comprises a base portion 66, having a circular shape around the axis A and configured to be mounted to the circuit board 10, as for example depicted in FIG. 4.

[0114] When the orientation light output diluting element 64 is mounted to the circuit board 10, the base portion 66 surrounds the at least one orientation light source 62, which may be located in a central part of the base portion 66 on or close to the axis A, as for example depicted in FIG. 4.

[0115] The orientation light output diluting element 64 further comprises a front portion 68. When the orientation light output diluting element 64 is mounted to the circuit board 10, its front portion 68 is spaced from the circuit board 10 and the at least one orientation light source 62, as it is depicted in FIG. 4.

[0116] The orientation light output diluting element 64 comprises a support portion 70 extending between the base portion 66 and the front portion 68 for supporting the front portion 68.

[0117] The support portion 70 has rotational symmetry with respect to the axis A as well. The support portion 70 may have a curved shape, as it is exemplarily depicted in FIGS. 5 to 7. The support portion 70 may in particular be formed similar to a cup, with a narrow portion having a first diameter at an end facing the base portion 66 and with a wide portion having a second diameter at the front portion 68, wherein the second diameter is larger than the first diameter.

[0118] The front portion 68 of the orientation light output diluting element 64 may be or may include a light sieve 69, comprising light passing portions 72 and light blocking barrier portions 74.

[0119] For clarity of illustration, only some of the light passing portions 72 and only some of the light blocking barrier portions 74 are exemplarily denoted with reference signs in FIGS. 5 and 6.

[0120] The light blocking barrier portions 74 are formed by the material of the front portion 68 between the light passing portions 72. The light passing portions 72 are formed by openings through the front portion 68 of the orientation light output diluting element 64.

[0121] The material forming the front portion 68 of the orientation light output diluting element 64 may be partly reflective and partly translucent for the light emitted by the at least one orientation light source 62. In such a configuration, the light blocking barrier portions 74 are partly reflective and partly translucent for light emitted by the at least one orientation light source 62.

[0122] In an alternative embodiment, the material forming the front portion 68 of the orientation light output diluting element 64 may be opaque and at least partly reflective for the light emitted by the at least one orientation light source 62, so that the light blocking barrier portions 74 are opaque and at least partly reflective for light emitted by the at least one orientation light source 62.

[0123] In the exemplary embodiment of FIGS. 5 to 7, at least the inside of the orientation light output diluting element 64 is at least partly reflective for spreading the light emitted by the at least one orientation light source 64. The resulting set of light rays within the chamber underneath orientation light output diluting element 64 may form the basis for fine tuning the light output of the orientation light output diluting element 64 by varying the numbers and sizes of the light passing portions 72 and light blocking barrier portions 74. In this way, a high level of luminance uniformity across the orientation light output diluting element 64 may be achieved.

[0124] The orientation light output diluting element 64 be made from standard, non-optical materials that are inexpensive and that are not sensitive to harsh environmental conditions, such as heat, UV radiation or other stresses to which an aircraft tail navigation light may be exposed in operation.

[0125] The orientation light output diluting element 64 may in particular be made from a non-UV sensitive material, such as Ultem 9085 or another engineering plastics such as PES, or PA.

[0126] The base portion 66, the front portion 68 and the support portion 70 may be made from the same material. The base portion 66, the front portion 68 and the support portion 70 may in particular be formed integrally with each other, providing an integrated orientation light output diluting element 64. The orientation light output diluting element 64 may be provided in the form of a light cap that can be placed over the at least one orientation light source 62.

[0127] The integrated orientation light output diluting element 64/the light cap may be manufactured by 3D printing, injection molding or another suitable production method.

[0128] In the embodiment depicted in FIGS. 5 to 7, the light passing portions 72 are provided as openings 72 formed in the front portion 68 of the orientation light output diluting element 64.

[0129] The openings 72 are in particular arranged as annular arrangements along multiple concentric circles, which have different radii and which are centered on axis A.

[0130] In the exemplary embodiment depicted in FIGS. 5 to 7, the openings 72 are arranged in four annular arrangements along four circles, with all circles comprising the same number of openings 72. This is, however, only an exemplary configuration, and the openings may be provided in other configurations as well.

[0131] The openings 72 may, for example, be arranged along circles comprising different numbers of openings 72. The openings 72 may also be arranged in different patterns, for example in a rectangular or honeycomb pattern.

[0132] Additionally, a central opening, which is not part of any of the four annular arrangements, may be formed at the center of the front portion 68.

[0133] In the exemplary embodiment depicted in FIGS. 5 to 7, the diameter of the openings 72 increases with increasing distance from the axis A. In other words, the openings 72 of an outer circle of openings 72 having a first radius have a larger diameter than the openings 72 of an inner circle of openings 72 having a second radius that is smaller than the first radius. The different diameters of the openings 72 may compensate for a lower intensity of the light emitted by the at least one orientation light source 62 that reaches the outer regions of the front portion 68 of the orientation light output diluting element 64, as compared to the light emitted by the at least one orientation light source 62 that reaches the inner regions of the front portion 68. Such a configuration of the openings 72 may allow for generating a highly homogeneous orientation light output.

[0134] The openings 72 may have diameters in the range in the range of between 0.4 mm and 4 mm. The largest openings 72, which are located at the outer periphery of the front portion 68, may have diameters in the range in the range of between 2.5 mm and 4 mm. The smallest openings 72, which are located in a central part of the front portion 68, may have diameters in the range in the range of between 0.4 mm and 1.5 mm.

[0135] The front portion 68 of the orientation light output diluting element 64 may have an extension, in particular a diameter, D of at least 10 mm. The front portion 68 of the orientation light output diluting element 64 may in particular have an extension, in particular a diameter, D of between 30 mm and 70 mm, further in particular an extension, in particular a diameter, D of between 40 mm and 60 mm.

[0136] The orientation light output diluting element 64 may have a height H (see FIG. 7) in the range of between 10 mm and 20 mm.

[0137] The closest distance between adjacent openings 72 may be less than 5 mm. The closest distance between adjacent openings 72 may in particular be less than 4.5 mm, more particularly the closest distance between adjacent openings 72 may be less than 4.3 mm.

[0138] In an alternative embodiment, which is not shown explicitly in the figures, the light passing portions 72 may be provided by a transparent or nearly transparent material that allows a large portion of the light emitted by the at least one orientation light source 62 to pass through.

[0139] The transparent or nearly transparent material may by provided in the form of inserts and may be introduced into the openings 72 that are formed in the front portion 68 of the orientation light output diluting element 64.

[0140] Alternatively, the front portion 68 of the orientation light output diluting element 64 may be formed integrally to comprise highly light transmissive light passing portions 72 and to comprise at least partly reflective, and potentially fully opaque, light blocking barrier portions 74.

[0141] The front portion 68 of the orientation light output diluting element 64 may, for example, be formed from a transparent material, and the light blocking barrier portions 74 may be formed by applying an at least partly reflective, and potentially fully opaque, coating to selected portions of the front portion 68 of the orientation light output diluting element 64. This coating may be applied to the inside or to the outside of the front portion 68 of the orientation light output diluting element 64.

[0142] The front portion 68 of the orientation light output diluting element 64 with the light passing portions 72 may provide a light emission surface of the orientation lighting assembly 6 that has a light emission surface area of at least 500 mm.sup.2, in particular a light emission surface area more than least 1000 mm.sup.2.

[0143] In contrast, the area of the light emission surface of the navigation lighting assembly 4, which is provided by the at least one navigation light source 42/by the combination of the at least one navigation light source 42 and the optical system 44 arranged over the at least one navigation light source 42, may be smaller than 5 mm.sup.2, in particular smaller than 2 mm.sup.2.

[0144] As a result, when viewed from a certain distance, in particular from a distance of more than 10 m, from the aircraft tail navigation light 106c, the light emitted by the navigation lighting assembly 4 is perceived as a point source. In contrast, the light emitted by the orientation lighting assembly 6 is perceived as an illuminated area having an extension in the horizontal direction and in the vertical direction, respectively. The horizontal and vertical extension of the illuminated area provides a visual reference that allows a pilot of a trailing aircraft, flying behind the aircraft 100 that is equipped with an aircraft tail navigation light 106c according to an exemplary embodiment of the invention, to evaluate the distance between the trailing aircraft and the leading aircraft 100 based on the perceived illuminated area.

[0145] Further, since the light emitted by the orientation lighting assembly 6 has a considerably lower light intensity than the light emitted by a conventional aircraft tail navigation light 106c, the risk of glaring the pilot of the trailing aircraft and the resulting risks of eye fatigue and reduced dark adaption of the pilot's eyes are considerably reduced. In consequence, it is easier for the pilot of the trailing aircraft to safely navigate the trailing aircraft behind the leading aircraft 100, in particular for receiving fuel from the leading aircraft 100 via an in-flight fueling device provided by the leading aircraft 100.

[0146] In aircraft tail navigation lights according to exemplary embodiments of the invention, the navigation light intensity may be at least 10 times as large, in particular between 10 times and 100 times as large, as the orientation light intensity. The difference in light intensity may stem from different intrinsic intensities of the at least one navigation light source and the at least one orientation light source or from different ways of driving/supplying current to the at least one navigation light source and the at least one orientation light source. It is also possible that the light intensities, as emitted by the at least one navigation light source and the at least one orientation light source, are substantially the same or similar and that the difference in light intensities of the navigation light output and the orientation light output stems from the optical effect of the orientation light output diluting element.

[0147] While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.