FOREIGN PRIORITY

This application claims priority to European Patent Application No. 19210630.0 filed Nov. 21, 2019, the entire contents of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention is in the field of exterior aircraft lighting. In particular, the present invention relates to exterior aircraft lights having a modular structure.

BACKGROUND

Almost all aircraft are equipped with exterior lighting systems. For example, large commercial aircraft have many different exterior aircraft lights. An exemplary group of exterior aircraft lights are lights for passive visibility and signalling, such as navigation lights and anti-collision lights. Another exemplary group of exterior aircraft lights are headlights that allow the pilots to view the area in front of them, when they are seated in the cockpit, such as taxi lights, take-off lights, landing lights, and runway turn-off lights. Yet another exemplary group of exterior aircraft lights are scan lights that allow the inspection of the aircraft structure in the dark, such as wing scan lights. A sudden failure of an exterior aircraft light may have severe safety implications. As a consequence, an aircraft may have to be kept on the ground, until a broken exterior aircraft light is repaired or replaced.

Accordingly, it would be beneficial to provide exterior aircraft light components and exterior aircraft lights that allow for an improved reliability of the aircraft lighting system.

SUMMARY

Exemplary embodiments of the invention include a replaceable light head for an exterior aircraft light, comprising: a mounting structure for attaching the replaceable light head to the exterior aircraft light; a power terminal, coupleable to an internal power supply of the exterior aircraft light; at least one light source, coupled to the power terminal for receiving power from the internal power supply of the exterior aircraft light; a data interface, coupleable to a controller of the exterior aircraft light; and a memory, coupled to the data interface and configured to receive and store usage data of the internal power supply of the exterior aircraft light.

Exemplary embodiments of the invention allow for an effective monitoring of the operation of the internal power supply of an exterior aircraft light and may, thus, allow for a timely replacement of the internal power supply and/or associated components, before a sudden failure occurs. The replaceable light head is an effective carrier for information about the operation of the internal power supply. In many exterior aircraft lights, the replaceable light head has a much shorter life cycle than the exterior aircraft light as a whole and than the internal power supply. When removing the replaceable light head from the exterior aircraft light, the usage data of the internal power supply may be conveniently read out and may be analysed for evaluating an operating status of the internal power supply. An informed decision with respect to the internal power supply can be made for the next scheduled maintenance interval and/or for an extraordinary maintenance. The shorter life cycle of the at least one light source, as compared to the circuit components of the internal power supply, can be made use of by using the replacement of the light head for communicating information about the internal power supply to an entity outside of the exterior aircraft light.

The replaceable light head has a power terminal that is coupleable to an internal power supply of the exterior aircraft light. In other words, upon installing the replaceable light head in the exterior aircraft light, the power terminal may be coupled to the internal power supply of the exterior aircraft light. When removing the replaceable light head from the exterior aircraft light, the power terminal may be de-coupled from the internal power supply of the exterior aircraft light. When coupling the power terminal to the internal power supply, an electric connection between the internal power supply and the power terminal and, thus, an electric connection between the internal power supply and the at least one light source of the replaceable light head can be established.

The replaceable light head has a data interface, coupleable to the controller of the exterior aircraft light. When installing the replaceable light head in the exterior aircraft light, the data interface may be coupled to the controller of the exterior aircraft light. When removing the replaceable light head from the exterior aircraft light, the data interface may be de-coupled from the controller of the exterior aircraft light. When installing the replaceable light head in the exterior aircraft light, a data channel between the controller of the exterior aircraft light and the data interface and, thus, between the controller of the exterior aircraft light and the memory of the replaceable light head may be established.

The replaceable light head has a power terminal coupleable to an internal power supply of the exterior aircraft light and a data interface coupleable to a controller of the exterior aircraft light. In this way, the replaceable light head has a power and data interface, which allows reception of power for operating the at least one light source on the one hand and allows for reception of usage data of the internal power supply of the exterior aircraft light for storage in the memory on the other hand.

The replaceable light head has at least one light source. The at least one light source may be at least one LED. With LEDs being reliable, compact, and power efficient light sources, a compact, reliable and efficient implementation of the replaceable light head may be achieved.

The replaceable light head has a memory that is configured to receive and store usage data of the internal power supply of the exterior aircraft light. The memory is able to store data and to maintain said data in the memory. In particular, the memory is able to maintain the data in the absence of electrical power. The memory may be configured to store the usage data of the internal power supply of the exterior aircraft light in a dedicated memory portion and/or in accordance with a suitable data storage protocol. The memory may for example be an EEPROM or a flash memory or any other suitable type of memory that allows for reliably storing the usage data of the internal power supply in the demanding environment of an exterior aircraft light. The memory may in particular be suitable for maintaining the usage data after removing the replaceable light head from the exterior aircraft light.

The replaceable light head has a power terminal coupleable to the internal power supply of the exterior aircraft light. The term internal power supply refers to an entity within the exterior aircraft light that is configured to provide the required energy for generating the light output of the exterior aircraft light. The exterior aircraft light in turn may be coupled to an aircraft on-board power supply network. When the replaceable light head is installed in the exterior aircraft light, power form the aircraft on-board power supply network may be received at the exterior aircraft light and may be provided to the replaceable light head via the internal power supply. The internal power supply may therefore also be seen as a power conditioning circuit, receiving power from the aircraft on-board power supply network and providing power, suitable for operating the at least one light source in a desired manner.

According to a further embodiment, the usage data of the internal power supply of the exterior aircraft light comprises at least one of operating time of the internal power supply and operating temperature of the internal power supply. In this way, the number of operating hours and/or the temperature during operation of the internal power supply can be logged in the memory of the replaceable light head. The combination of operating time and operating temperature may be evaluated as a good indicator for the strain exerted onto the internal power supply. For example, extended operations of the internal power supply in very hot conditions, such as on an airport in the desert or a desert-like region, may be recorded and may be taken into account when evaluating the residual life time of the internal power supply. The operating temperature may be an ambient temperature within the exterior aircraft light. It is also possible that the operating temperature is the operating temperature within one or more circuit components of the exterior aircraft light, in particular within one or more circuit components of the internal power supply of the exterior aircraft light. Both the ambient temperature and the operating temperature of a circuit component may be valid indicators for the temperature strain exerted onto the internal power supply.

According to a further embodiment, the replaceable light head further comprises a light sensor, arranged to monitor the at least one light source, wherein the light sensor is coupled to the memory and wherein the memory is configured to store light sensor data, output by the light sensor. In this way, the replaceable light head may not only act as a carrier for the usage data of the internal power supply of the exterior aircraft light, but also as a carrier for information about the performance of the at least one light source. In this way, when replacing the light head of the exterior aircraft light, it may be determined whether the at least one light source degraded in an expected manner or whether abnormalities in the performance of the at least one light source occurred. Such abnormalities may be an indicator for a malfunction of the internal power supply of the exterior aircraft light and/or may help in adapting the next light head to the particular exterior aircraft light in question.

According to a further embodiment, the replaceable light head further comprises a temperature sensor, arranged to monitor an operating temperature of the replaceable light head, wherein the temperature sensor is coupled to the memory and wherein the memory is configured to store temperature sensor data, output by the temperature sensor. In this way, additional context with respect to the operation of the replaceable light head may be stored in the memory and may be available for analysis, after the replaceable light head has been removed from the exterior aircraft light. The temperature sensor data may for example explain an unexpectedly quick degradation of the performance of the at least one light source. As a further example, the temperature sensor data of the temperature sensor of the replaceable light head may be related to the operating temperature of the internal power supply, in order to potentially detect abnormal temperature gradients between the internal power supply and the replaceable light head and to explain operating faults therefrom.

According to a further embodiment, the replaceable light head further comprises at least one of a position sensor, a velocity sensor, and an acceleration sensor, configured to issue a trigger signal, indicative of an aircraft take-off, to the memory. In this way, the memory may store usage data of the internal power supply and/or light sensor data and/or temperature sensor data in conjunction with an indication whether or not the aircraft is on the ground. The mentioned sensors may be configured to issue the trigger signal on the basis of the raw sensor data or may be configured to issue the trigger signal on the basis of some post-processing of the sensor data. For example, the velocity sensor may issue the trigger signal in case a velocity of more than 250 km/h is reached. The position sensor may deduce the reaching of such a velocity threshold by evaluating the gradient of the position. In another example, the acceleration sensor may issue the trigger signal in case a typical take-off acceleration pattern is detected, such as an acceleration in excess of a predefined acceleration threshold value for more than 20 s.

According to a further embodiment, the memory is configured to store usage data of the internal power supply after receipt of the trigger signal. In a particular embodiment, the memory may be configured to store usage data of the internal power supply continuously after the first receipt of the trigger signal. In this way, the memory may distinguish between a functional test of the replaceable light head on the ground and the intended operation of the replaceable light head within an exterior aircraft light. It can thus be ensured that usage data will only be stored, after the replaceable light head is installed in the exterior aircraft light and actually used during operation of the aircraft. Time periods, in which the replaceable light head is waiting for its operation in the exterior aircraft light and which may distort the analysis of the usage of the internal power supply, may thus be eliminated. It is also possible that the memory is configured to wait for the trigger signal after each power-up operation, before starting to store usage data of the internal power supply. In this way, each take-off will start a new data storage cycle. The memory may further be configured to store light sensor data and/or temperature sensor data after receipt of the trigger signal.

According to a further embodiment, the memory is configured to store erosion data indicative of a state of erosion of a lens cover of the exterior aircraft light. In this way, the replaceable light head may additionally be used as a carrier for information about the state of the lens cover of the exterior aircraft light, such that a targeted replacement of the lens cover may be carried out. Also, the erosion data may help in determining whether the exterior aircraft was subject to abnormal impacts, particularly adverse operating conditions, etc. The state of erosion may be determined by detecting light diffusely reflected by the lens cover. This may be done via above discussed light sensor, e.g. in response to a predefined lens cover illumination pattern, or via another light sensor, dedicated to detecting diffusely reflected light from the lens cover.

According to a further embodiment, the exterior aircraft light, to which the replaceable light head may be mounted, is a multi-function exterior aircraft light, having at least two light heads, and the memory of the replaceable light head is configured to store data copied from another light head. In other words, the replaceable light head may be installed in an operating environment, where two or more light heads are arranged in the exterior aircraft light. In addition to being configured to store usage data of the internal power supply of the exterior aircraft light, the memory of the replaceable light head may be configured to store data copied from one or more of the other light head(s) present in the exterior aircraft light. In the particular example of the exterior aircraft light having two light heads, such as a navigation light head and an anti-collision light head, each one of the two light heads may be a replaceable light head as described herein. Further, one or both of these light heads may have a memory that is configured to store data copied from the respectively other light head. The data copied from another light head may be usage data of the internal power supply and/or data regarding the other light head, such as light sensor data and/or temperature sensor data of the other light head, and/or erosion data regarding the lens cover of the exterior aircraft light. By storing copied data, redundancy between the multiple light heads may be achieved. In case the data on one of the memories is corrupted, the other memory may still be used to convey usage data of the internal power supply and potentially other data, when removed from the exterior aircraft light. Data mirroring may take place between the memories of the multiple light heads.

According to a further embodiment, the mounting structure comprises a circuit board, with the at least one light source and the memory being mounted to the circuit board. The circuit board may in particular be a printed circuit board. In this way, the mounting structure integrates the functions of mechanically attaching the replaceable light head to the exterior aircraft light and providing the electric connections to the electric components of the replaceable light head.

According to a further embodiment, the replaceable light head further comprises an optical system arranged over the at least one light source and mounted to the mounting structure. The optical system may comprise one or more lenses and/or one or more shutters and/or one or more reflectors. The terminology of the optical system being arranged over the at least one light source is not meant to imply a particular orientation of the optical system in the replaceable light head. Rather, the optical system is meant to be arranged in such a way with respect to the at least one light source that it transforms the light output of the at least one light source into a desired light output of the exterior aircraft light. The at least one light source and the optical system can therefore be said to jointly provide a light put of the exterior aircraft light. In case the mounting structure comprises a circuit board, the optical system may be attached to the circuit board, in particular arranged over the at least one light source and attached to the circuit board in one or more mounting spots around the at least one light source.

According to a further embodiment, the replaceable light head is configured to provide at least one of a navigation light output, a white strobe anti-collision light output, and a red flashing beacon light output. In particular, the replaceable light head may be configured to provide a navigation light output that satisfies legal requirements and/or design parameters of the navigation lighting system for at least a part of the space around the aircraft. Additionally/alternatively, the replaceable light head may be configured to provide a white strobe anti-collision light output that satisfies legal requirements and/or design parameters of the white strobe anti-collision lighting system for at least a part of the space around the aircraft. Alternatively/additionally, the replaceable light head may be configured to provide a red flashing beacon light output that satisfies legal requirements and/or design parameters of the beacon lighting system for at least part of the space around the aircraft. Exemplary legal requirements for navigation lights are given in Federal Aviation Regulations (FAR) sections 25.1385, 25.1387, 25.1389, 25.1391, 25.1393, 25.1395, and 25.1397. Exemplary legal requirements for white strobe anti-collision lights and red flashing beacon lights are given in Federal Aviation Regulations (FAR) section 25.1401. It is pointed out that the functions of navigation lighting, white strobe anti-collision lighting, and red flashing beacon lighting may be combined in a single replaceable light head or may be distributed among different replaceable light heads of one exterior aircraft light or may be distributed among replaceable light heads of different exterior aircraft lights.

Exemplary embodiments of the invention further include an exterior aircraft light, comprising: a power input, coupleable to an aircraft on-board power supply network; an internal power supply, coupled to the power input; a controller; and a replaceable light head, as described in any of the embodiments above; wherein the power supply terminal of the replaceable light head is coupled to the internal power supply and wherein the data interface of the replaceable light head is coupled to the controller. The additional features, modifications, and effects, described above with respect to the replaceable light head, apply to the exterior aircraft light in an analogous manner. The controller is coupled to the internal power supply and is configured to effect/control the power transfer from the power input to the at least one light source via the internal power supply. In this way, the controller is inherently aware of the operating times of the internal power supply and may convey said information to the memory via the data interface of the replaceable light head.

According to a further embodiment, the exterior aircraft light has a power supply temperature sensor, coupled to the controller. The controller may convey power supply temperature sensor data to the memory of the replaceable light head via the data interface.

According to a further embodiment, the exterior aircraft light is one of a navigation light, a white strobe anti-collision light, a red flashing beacon light, and a headlight. The term headlight may include any of a landing light, a take-off light, a runway turn-off light, and a taxi light. The exterior aircraft light may also be a multipurpose exterior aircraft light, combining two or more of said lighting functions. For example, the exterior aircraft light may be a combined aircraft navigation and white strobe anti-collision light. In case of such multi-purpose exterior aircraft lights, the different lighting functions may be distributed among different replaceable light heads or may be combined in a single replaceable light head. For example, a combined aircraft navigation and anti-collision light may have a first replaceable light head for the navigation lighting functionality and a second replaceable light head for the white strobe anti-collision lighting functionality.

Exemplary embodiments of the invention further include an aircraft comprising at least one exterior aircraft light, as described in any of the embodiments above. The additional features, modifications, and effects, described above with respect to the replaceable light head and with respect to the exterior aircraft light, apply to the aircraft in an analogous manner. The aircraft may in particular be an air plane, such as a commercial passenger air plane.

Exemplary embodiments of the invention further include a method of evaluating an operating status of an internal power supply of an exterior aircraft light, comprising: during operation of the exterior aircraft light, storing usage data of the internal power supply of the exterior aircraft light in a memory of a replaceable light head of the exterior aircraft light; removing the replaceable light head from the exterior aircraft light; and reading the usage data out of the memory and evaluating the operating status of the internal power supply of the exterior aircraft light from the usage data. The additional features, modifications, and effects, as described above with respect to the replaceable light head and with respect to the exterior aircraft light, apply to the method of evaluating the operating status of the internal power supply of the exterior aircraft light in an analogous manner.

The removing of the replaceable light head may take place at a regular maintenance interval or pursuant to the detection of a near end of life condition of the at least one light source or pursuant to the detection of any other condition requiring maintenance.

The reading out of the usage data may take place in a convenient working space separate from the aircraft, such as in a factory, a laboratory or similar setting. It is also possible that a diagnosis tool may be coupled to the memory of the replaceable light head for reading out the usage data, when the replaceable light head is still fully or partially installed in the exterior aircraft light. It is further possible that an initial evaluation of the operating status takes place via such diagnosis tool, while a full evaluation of the usage data takes place in a setting separate from the aircraft.

According to a further embodiment the method further comprises detecting an aircraft take-off; and starting the storing of usage data of the internal power supply of the exterior aircraft light in response to an aircraft take-off being detected. The storing of usage data may continue as long as the replaceable light head is installed in the exterior aircraft light, after a first aircraft take-off is detected. It is also possible that the storing of usage data is stopped, when the exterior aircraft light is powered down, such as when the aircraft is put to an overnight parking position. In that case, the storing of usage data may be re-started at the next aircraft take-off.

