# Patent

## Title
Method for diagnosing a speed brake system fault

## Abstract

A method of diagnosing a speed brake fault, where the method includes receiving a position signal from the at least one position sensor, determining a variation in the position signal relative to a reference position and diagnosing a fault in the speed brake system based on the variation.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. §119 to British Patent Application No. 13085147, filed May 13, 2013, the disclosure of which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
Contemporary aircraft may include speed brake systems, which may include control surfaces on each wing. The use of the control surfaces may increase drag to aid in the reduction of airspeed for a given thrust, which is especially beneficial during landing of the aircraft. Currently, after a fault occurs with the system, airlines or maintenance personnel attempt to identify the cause and fix it either during scheduled or most likely during unscheduled maintenance.
BRIEF DESCRIPTION OF THE INVENTION
In one embodiment, the invention relates to a method of diagnosing a speed brake fault in an aircraft having a speed brake system including multiple control surfaces, a handle for setting the position of the multiple control surfaces, and at least one control surface position sensor, the method includes receiving a position signal from the at least one position sensor, determining a variation in the position signal relative to a reference position, diagnosing a fault in the speed brake system based on the variation, and providing an indication of the diagnosed fault.



BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a schematic view of an aircraft having an exemplary speed brake system;
FIG. 2 is a perspective view of the aircraft of FIG. 1 and a ground system in which embodiments of the invention may be implemented; and
FIG. 3 is a flowchart showing a method of diagnosing a speed brake fault in an aircraft according to an embodiment of the invention.



DESCRIPTION OF EMBODIMENTS OF THE INVENTION
FIG. 1 schematically depicts a portion of an aircraft 10 that may execute embodiments of the invention and may include one or more propulsion engines 12 coupled to a fuselage 14, a cockpit 16 positioned in the fuselage 14, and wing assemblies 18 extending outward from the fuselage 14. A speed brake system 20 is included in the aircraft 10 and includes multiple control surfaces or spoilers 22 on each of the wing assemblies 18. The multiple spoilers 22 may include hinged surfaces mounted on each of the wing assemblies 18 to reduce the speed of the aircraft 10 and to increase the angle of descent for landing. The term spoiler is meant to include any control surface in the speed brake system 20 that increases the profile drag of the aircraft 10. While multiple spoilers have been illustrated it will be understood that the speed brake may be a single dedicated control surface. There are many different types of control surfaces and their use may depend on the size, speed, and complexity of the aircraft 10 on which they are to be used. Further, on some aircraft, they are hinged to and faired with the side or bottom of the fuselage. Regardless of their location, their purpose is the same. Such differing speed brake types are not germane to the embodiments of the invention and will not be described further herein. Further, while four spoilers 22 have been illustrated on each of the wing assemblies 18 it may be understood that there may be any number of spoilers 22 included in the speed brake system 20. Additional control surfaces 23, which serve other purposes including trailing edge flaps and forward edge slats, have been illustrated.
A speed brake handle 24 may be included in the cockpit 16 and may be operated by a pilot to set the position of the multiple spoilers 22. The speed brake handle 24 may provide an input to a speed brake drive 26, which may be used to move the multiple spoilers 22 into the position set by the speed brake handle 24. The term speed brake handle as used in this description is not limited to a physical brake handle, rather it relates to the control device used to set the position of the speed brakes. Throughout the early part of aviation, this control device was a handle and the term speed brake handle has now become generic to the control device used to set the speed brake position, regardless of whether the control device is an actual handle or a button on a touch-screen user interface. Therefore, the specific drive mechanisms may vary and have not been illustrated for the sake of clarity.
A speed brake handle sensor 25 or other suitable mechanism may be used for determining the position of the speed brake handle 24; that is, the set position of the speed brakes. In most aircraft, the speed brakes have a predetermined number of set positions, which correspond to different flight phases. While the speed brakes can be variably, even infinitely adjustable, typically the speed brakes have a predetermined number of fixed positions.
Further, one or more control surface position sensors or speed brake position sensors 28 may be included in the speed brake system 20 and each may output a position signal indicative of the position of at least one of the multiple spoilers 22. For example, a skew sensor may be operably coupled to each of the multiple spoilers 22 and indicate the angle of each of the multiple spoilers 22.
Referring now to FIG. 2, it may more easily be seen that a plurality of additional aircraft systems 29 that enable proper operation of the aircraft 10 may also be included in the aircraft 10 as well as a controller 30, and a communication system having a wireless communication link 32. The controller 30 may be operably coupled to the plurality of aircraft systems 29 including the speed brake system 20. For example, the speed brake drive 26, the speed brake handle 24, the speed brake handle sensor 25, and the one or more speed brake position sensors 28 may be operably coupled to the controller 30. Further, the position signal may be stored in a storage device on the aircraft 10 and accessed by the controller 30.
The controller 30 may also be connected with other controllers of the aircraft 10. The controller 30 may include memory 34, the memory 34 may include random access memory (RAM), read-only memory (ROM), flash memory, or one or more different types of portable electronic memory, such as discs, DVDs, CD-ROMs, etc., or any suitable combination of these types of memory. The controller 30 may include one or more processors 36, which may be running any suitable programs. The controller 30 may be a portion of an FMS or may be operably coupled to the FMS.
A computer searchable database of information may be stored in the memory 34 and accessible by the processor 36. The processor 36 may run a set of executable instructions to display the database or access the database. Alternatively, the controller 30 may be operably coupled to a database of information. For example, such a database may be stored on an alternative computer or controller. It will be understood that the database may be any suitable database, including a single database having multiple sets of data, multiple discrete databases linked together, or even a simple table of data. It is contemplated that the database may incorporate a number of databases or that the database may actually be a number of separate databases.
The database may store data that may include historical data related to the multiple spoilers 22 for the aircraft 10 as well as historical speed brake data related to a fleet of aircraft. The database may also include reference values including predetermined reference position values for the angle of multiple spoilers 22 when the speed brake handle 24 is in a variety of positions and variation reference values. The database may also include diagnosis criteria for determining various faults with the speed brake system 20.
Alternatively, it is contemplated that the database may be separate from the controller 30 but may be in communication with the controller 30 such that it may be accessed by the controller 30. For example, it is contemplated that the database may be contained on a portable memory device and in such a case, the aircraft 10 may include a port for receiving the portable memory device and such a port would be in electronic communication with the controller 30 such that the controller 30 may be able to read the contents of the portable memory device. It is also contemplated that the database may be updated through the wireless communication link 32 and that in this manner, real time information such as information regarding historical fleet wide data may be included in the database and may be accessed by the controller 30.
Further, it is contemplated that such a database may be located off the aircraft 10 at a location such as airline operation center, flight operations department control, or another location. The controller 30 may be operably coupled to a wireless network over which the database information may be provided to the controller 30.
While a commercial aircraft has been illustrated, it is contemplated that portions of the embodiments of the invention may be implemented anywhere including in a controller or computer 40 at a ground system 42. Furthermore, database(s) as described above may also be located in a destination server or a computer 40, which may be located at and include the designated ground system 42. Alternatively, the database may be located at an alternative ground location. The ground system 42 may communicate with other devices including the controller 30 and databases located remote from the computer 40 via a wireless communication link 44. The ground system 42 may be any type of communicating ground system 42 such as an airline control or flight operations department. The computer 40 may be any suitable type of computer and may include any suitable memory, processing units, etc.
One of the controller 30 and the computer 40 may include all or a portion of a computer program having an executable instruction set for detecting or diagnosing a speed brake fault in the aircraft 10. Such diagnosed faults may include improper operation of components as well as failure of components. As used herein the term diagnosing refers to a determination after the fault has occurred. This contrasts with prediction, which refers to a forward looking determination that makes the fault known in advance of when the fault occurs. Along with diagnosing, the controller 30 and/or computer 40 may detect the fault. Regardless of whether the controller 30 or the computer 40 runs the program for diagnosing the fault, the program may include a computer program product that may include machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media may be any available media, which can be accessed by a general purpose or special purpose computer or other machine with a processor. Generally, such a computer program may include routines, programs, objects, components, data structures, algorithms, etc. that have the technical effect of performing particular tasks or implementing particular abstract data types. Machine-executable instructions, associated data structures, and programs represent examples of program code for executing the exchange of information as disclosed herein. Machine-executable instructions may include, for example, instructions and data, which cause a general purpose computer, special purpose computer, or special purpose processing machine to perform a certain function or group of functions.
It will be understood that the aircraft 10 and computer 40 merely represent two exemplary embodiments that may be configured to implement embodiments or portions of embodiments of the invention. During operation, either the aircraft 10 and/or the computer 40 may diagnose a speed brake fault. By way of non-limiting example, while the aircraft 10 is being operated, the speed brake handle 24 may be utilized to set the position of the multiple spoilers 22. The speed brake handle sensor 25 may output a signal indicative of the position of the speed brake handle 24 and the speed brake position sensors 28 may output a position signal indicative of the position of the multiple spoilers 22. Each of the multiple spoilers 22 should behave the same when the speed brake handle 24 sets the position of the multiple spoilers 22 as it is not possible to set the spoilers 22 differently.
The controller 30 and/or the computer 40 may utilize inputs from the speed brake handle sensor 25, the speed brake position sensors 28, the database(s) and/or information from airline control or flight operations department to diagnose the speed brake fault or detect a fault that the airline maintenance crew were previously unaware of Among other things, the controller 30 and/or the computer 40 may analyze the data output by the speed brake position sensors 28 to determine differences between the movements of the multiple spoilers 22. The controller 30 and/or the computer 40 may also analyze the speed brake data to determine differences between the movement of the spoilers 22 and discrepancies between where the speed brake handle 24 has set the position and the actual position of the multiple spoilers 22 to diagnose faults in the speed brake system 20. The controller 30 and/or computer 40 may also determine the time it takes each of the multiple spoilers 22 to reach a specific position and determine timing differences based thereon. Thus, it will be understood that the controller 30 and/or the computer 40 may make any number of comparisons to determine differences with various thresholds to diagnose faults in the speed brake system 20. Once a speed brake fault has been diagnosed, an indication may be provided on the aircraft 10 and/or at the ground system 42. It is contemplated that the diagnosis of the speed brake fault may be done during flight, may be done post flight, may be done at the end of the day after any number of flights, or may be done after any number of flights. The wireless communication link 32 and the wireless communication link 44 may both be utilized to transmit data such that the fault may be diagnosed by either the controller 30 and/or the computer 40.
In accordance with an embodiment of the invention, FIG. 3 illustrates a method 100, which may be used for diagnosing a speed brake fault, which can include a failure. The method 100 begins at 102 by receiving a position signal from at least one of the one of the speed brake position sensors 28, which is indicative of a position of at least one of the multiple spoilers 22. Alternatively, this may include receiving multiple position signals from the speed brake position sensors 28, with each position signal corresponding to a different one of the multiple spoilers 22.
At 104, the controller 30 and/or the computer 40 may determine a variation in the position signal relative to a reference position value. For example, the determination may be made by comparing the position signal and the reference position value. The reference position value may include any number of reference values related to the speed brake system 20. For example, the reference position value may include a value related to a position of any of the multiple spoilers 22, historical information regarding the position of the at least one of the multiple spoilers 22, and theoretical information regarding the position of the at least one of the multiple spoilers. For example, the theoretical information may include a set position or predetermined position for one of the multiple spoilers 22. Furthermore, the reference position value may include a speed brake handle position. In such an instance, the method may include determining a position of the speed brake handle 24 such as by receiving an output from the speed brake handle sensor 25 to define the reference position value. Alternatively, the reference position values may be stored in one of the database(s) as described above.
In this manner, a variation may be determined from the position signal received and the reference value. For example, a variation may be determined between at least two of the multiple position signals, with one of the multiple position signals being treated as the reference position value. Determining the variation may include determining from the position signal a time for at least one of the multiple spoilers 22 to move to a set position. In this manner a variety of variations may be determined including a variation in the time it takes one of the multiple spoilers 22 to reach its maximum angle after the speed brake handle 24 moves as compared to historical timings for that particular aircraft and/or related to the fleet, a variation in the time it takes one of the multiple spoilers 22 to be deployed after landing as compared to historical timings for that particular aircraft and/or related to the fleet, etc. Any number of variations may be determined. Including that determining the variation may include determining variations in the position signals for the multiple spoilers relative to multiple corresponding reference positions. In such an instance the multiple corresponding reference positions may be values related to angles of deployed spoilers. More specifically, the reference positions may include historical information regarding the angles of deployed spoilers.
At 106, the controller 30 and/or the computer 40 may diagnose a fault in the speed brake system 20 based on the variation. For example, a fault in the speed brake system 20 may be diagnosed when the variation comparison has been determined to satisfy a predetermined threshold value. In this manner, the controller 30 and/or the computer 40 may determine if the variation comparison is acceptable. The term “satisfies” the threshold is used herein to mean that the variation comparison satisfies the predetermined threshold, such as being equal to, less than, or greater than the threshold value. It will be understood that such a determination may easily be altered to be satisfied by a positive/negative comparison or a true/false comparison. For example, a less than threshold value can easily be satisfied by applying a greater than test when the data is numerically inverted. Such a threshold may be defined based on the tolerance for the various components being compared including the tolerance for the sensors being used. For example, if the position comparison includes comparing a position signal of one of the multiple spoilers 22 to a reference value then the threshold may be defined by tolerances for the spoilers 22 and/or the speed brake position sensors 28. Alternatively, if the controller 30 and/or the computer 40 is tracking the variation over time of each set speed brake position to the sensed speed brake position, then the variation reference value may be related to an acceptable change in the variation over time.
For example, a fault may be diagnosed when the determined variations indicates one spoiler differs from its historical angle for a given speed brake input position. For example, a fault may be diagnosed as a spoiler position sensor fault or a fault with an actuator when it is determined that the angle of a spoiler 22 when deployed differs from its historical angle while the other of the multiple spoilers are determined to be at correct positions. Further, a fault with an interlock for the spoiler 22, such as an interlock cable for the spoiler 22, may be diagnosed when the variations indicate that the position of all of the multiple spoilers on a wing differ from the historical information. A fault may be diagnosed with a speed brake control unit when the variation indicates that all of the multiple spoilers are not deployed and it is determined that the handle position corresponds to a deployment position of the multiple spoilers.
At 108, the controller 30 and/or the computer 40 may provide an indication of the fault in the speed brake system 20 diagnosed at 106. The indication may be provided in any suitable manner at any suitable location including in the aircraft 10 and at the ground system 42. By way of non-limiting example, the indication may be provided on a primary flight display (PFD) in the cockpit 16 of the aircraft 10.
In implementation, the reference values and comparisons may be converted to an algorithm to diagnose faults in the speed brake system 20. Such an algorithm may be converted to a computer program including a set of executable instructions, which may be executed by the controller 30 and/or the computer 40. The computer program may also take into account various information such as binary flags for commanded operations from the pilot and/or auto pilot as well as standard parameters recorded by onboard systems such as altitude and air/ground speed in diagnosing the fault in the speed brake system 20. Such a computer program may determine faults including out of range sensors readings, speed brake handle faults, speed brake/spoiler position faults, etc. Indications may then be given as to the time proximity of when the manifestation of the fault is likely to occur and the severity of the fault type. If the controller 30 ran the program, then the suitable indication may be provided on the aircraft 10 and/or may be uploaded to the ground system 42. Alternatively, if the computer 40 ran the program, then the indication may be uploaded or otherwise relayed to the aircraft 10. Alternatively, the indication may be relayed such that it may be provided at another location such as an airline control or flight operations department.
It will be understood that the method 100 of diagnosing a speed brake fault is flexible and the method illustrated is merely for illustrative purposes. For example, the sequence of steps depicted is for illustrative purposes only, and is not meant to limit the method 100 in any way as it is understood that the steps may proceed in a different logical order or additional or intervening steps may be included without detracting from embodiments of the invention. By way of non-limiting example, variation comparisons may be defined over a number of flights of the aircraft 10 to define multiple variation comparisons. The diagnosis of the fault may be based on the multiple variation comparisons. More specifically, a fault may be diagnosed when the variation parameter exceeds the variation reference value a predetermined number of times over a predetermined number of flights. Alternatively, the fault may be diagnosed based on data from a single flight. Further, the method may include determining the number of position signals that are outside a defined range for each spoiler 22 and such information may be compared to historic data for that particular aircraft and related to the fleet. Further, it is contemplated that maintenance data related to predicted faults or previously diagnosed faults in the speed brake system 20 may be received by the controller 30 and/or the computer 40. The received maintenance data may indicate an accuracy of previous diagnosed faults or predicted faults. Based on such information the controller 30 and/or the computer 40 may further diagnose the fault based on the received maintenance data including specifically diagnosing the fault type or severity of the fault.
Technical effects of the above described embodiments include that data gathered by the aircraft during flight may be utilized to diagnose a speed brake fault. The above described embodiments may result in many benefits including reduced maintenance times and the operational impact of faults and issues due to the speed brake system faults. Particularly there may be a reduction in the time required to diagnose an issue and issues may be diagnosed accurately. This allows for cost savings by reducing maintenance cost, rescheduling cost, and minimizing operational impacts including minimizing the time aircraft are grounded.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

## Claims

1. A method of diagnosing a speed brake fault in an aircraft, comprising:
receiving a position signal from the at least one position sensor associated with a set of control surfaces;
storing the position signal in a storage device on the aircraft;
determining during flight, by a controller on the aircraft, a variation in the position signal based on at least one of predicted faults or previously diagnosed faults;
diagnosing during flight, by the controller, a fault in a speed brake system based on the variation; and
generating, by the controller, an indication of the diagnosed fault, and providing the indication to at least one of the aircraft or a ground station.

2. The method of claim 1 wherein the receiving the position signal comprises receiving a set of position signals, a subset of the position signals corresponding to disparate control surfaces included in the set of control surfaces.

3. The method of claim 2 wherein determining the variation comprises determining variations in the position signals for disparate control surfaces included in the set of control surfaces relative to a set of reference positions.

4. The method of claim 3 wherein the reference position value at a first time differs from the reference position value at a second time.

5. The method of claim 3 wherein a subset of the reference positions are values related to angles of deployed control surfaces.

6. The method of claim 5 wherein the reference positions comprise historical information regarding the angles of deployed control surfaces.

7. The method of claim 6 wherein the fault is diagnosed when the determined variations indicate a subset of the control surfaces differ from their historical angle.

8. The method of claim 7 wherein the fault is diagnosed when it is further determined that the subset of the control surfaces are determined to be at correct positions.

9. The method of claim 8 wherein the fault is diagnosed as a fault with a control surface position sensor or a fault with an actuator.

10. The method of claim 6 wherein the fault is diagnosed when the variations indicate that the position of the set of control surfaces on a wing differ from the historical information.

11. The method of claim 10 wherein the fault is diagnosed as a fault with an interlock for a subset of the control surfaces.

12. The method of claim 6 wherein the received historical information indicates an accuracy of the previously diagnosed fault.

13. The method of claim 3, further comprising determining a handle position, which controls an angle of a subset of the control surfaces.

14. The method of claim 13 wherein the fault is diagnosed when the variation indicates that a subset of the control surfaces are not deployed and the controller determines that the handle position corresponds to a deployment position of a subset of the control surfaces.

15. The method of claim 1 wherein the control surfaces comprise spoilers.

16. The method of claim 1 wherein the variation in the position signal is based in part on a tolerance of the position sensor or the control surfaces.