Patent Publication Number: US-2022212782-A1

Title: Distributed trailing edge actuation systems and methods for aircraft

Description:
RELATED APPLICATION 
     This patent claims the benefit under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 63/134,824, titled “Distributed Trailing Edge Actuation Systems and Methods for Aircraft,” filed Jan. 7, 2021, which is hereby incorporated by this reference in its entirety. 
    
    
     FIELD OF THE DISCLOSURE 
     This disclosure relates generally to aircraft and, more particularly, to distributed trailing edge systems and methods for aircraft. 
     BACKGROUND 
     Many aircraft employ high lift devices, sometimes referred to as auxiliary airfoils or movable control surfaces, along the leading and trailing edges of the wings. For example, flaps are a common type of high lift device that are movably coupled along the trailing edge of a wing. The flaps may be moved (e.g., tilted) downward from the trailing edge of the wing to change the shape of the wing to generate more or less lift. The flaps are often deployed during takeoff and landing, for instance, to generate more lift at slower speeds. 
     SUMMARY 
     An example aircraft disclosed herein includes a wing, a flap coupled to the wing, the flap movable between a stowed position and a deployed position, and a distributed trailing edge (DTE) actuation system including a flap actuator coupled to the wing to move the flap. The flap actuator includes an integrated hydraulic powered actuator and electric powered actuator. The flap actuator is operable in a hydraulic powered mode in which the hydraulic powered actuator is activated to move the flap, an electric powered mode in which the electric powered actuator is activated to move the flap, and a hybrid mode in which the hydraulic power actuator and the electric powered actuator are activated simultaneously to move the flap. 
     An example aircraft disclosed herein includes a left wing, a right wing, flaps movable relative to trailing edges of the left and right wings, and a distributed trailing edge (DTE) actuation system including flap actuators coupled to the left and right wings to move the flaps. Each of the flap actuators is a rotary actuator including an integrated hydraulic powered actuator and electric powered actuator. The DTE actuation system also includes actuator control electronics (ACEs), wherein each of the hydraulic powered actuators of the flap actuators is controllable by at least two of the ACEs. 
     An example method disclosed herein includes determining an engine of an aircraft has failed. The failure of the engine causes a reduction in hydraulic power in an aircraft hydraulic system. The aircraft includes a flap actuator to move a flap relative to a trailing edge of a wing. The flap actuator includes an integrated hydraulic powered actuator and electric powered actuator. The example method further includes, in response to determining the engine has failed, operating the flap actuator in a hybrid mode in which the hydraulic powered actuator and the electric powered actuator are activated simultaneously to move the flap. 
     An example flap actuator for an aircraft is disclosed herein. The flap actuator includes a crank arm rotatable about an axis. The crank arm is to be coupled to a flap of the aircraft via a linkage assembly. The flap actuator also includes a hydraulic powered actuator coupled to the crank arm. The hydraulic powered actuator is to rotate the crank arm when activated. The flap actuator further includes an electric powered actuator coupled to the crank arm. The electric powered actuator is to rotate the crank arm when activated. 
     An example aircraft disclosed herein includes a wing, a flap, and a rotary flap actuator coupled to the wing. The rotary flap actuator is to move the flap between a stowed position and a deployed position. The rotary flap actuator includes an integrated hydraulic powered actuator and electric powered actuator. 
     An example flap actuator for an aircraft is disclosed herein. The flap actuator includes a crank arm, a hydraulic powered actuator coupled to the crank arm, and an electric powered actuator coupled to the crank arm. The hydraulic powered actuator and the electric powered actuator are simultaneously operable to rotate the crank arm. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example aircraft in which the examples disclosed herein can be implemented. 
         FIG. 2A  is a schematic diagram of an example distributed trailing edge (DTE) actuation system including an example DTE control system.  FIG. 2A  show components of the DTE control system for hydraulically controlling one or more flap actuators of the aircraft of  FIG. 1 . 
         FIG. 2B  is schematic diagram of the example DTE actuation system of  FIG. 2A  showing example components of the DTE control system for electrically controlling the one or more flap actuators of the aircraft of  FIG. 1 . 
         FIG. 3A  is a side view of an example flap actuator of the example DTE actuation system of  FIG. 2A  and an example linkage system used to move an example flap.  FIG. 3A  shows the example flap in a stowed position. 
         FIG. 3B  is a side view of the example flap actuator, example linkage assembly, and example flap of  FIG. 3A  showing the example flap in a deployed position. 
         FIG. 4A  illustrates an example flap actuator of the example DTE actuation system of  FIGS. 2A and 2B .  FIG. 4A  shows a partial cross-sectional view of an example hydraulic powered actuator of the example flap actuator and a schematic diagram of an example hydraulic control module used to control the hydraulic powered actuator.  FIG. 4A  shows an example valve of the example hydraulic control module in a first state in which pressurized hydraulic fluid is supplied to the example hydraulic powered actuator to move an example crank arm in a first direction. 
         FIG. 4B  shows the example valve of the example hydraulic control module of  FIG. 4A  in a second state in which pressurized hydraulic fluid is supplied to the example hydraulic powered actuator to move the example crank arm in a second direction. 
         FIG. 4C  shows the example hydraulic powered actuator of  FIGS. 4A and 4B  in a bypass mode. 
         FIG. 5  is a cross-sectional view of the example flap actuator taken along line A-A of  FIG. 4C .  FIG. 5  shows the example hydraulic powered actuator and an example electric powered actuator of the example flap actuator. 
         FIG. 6  is a flowchart representative of machine readable instructions to implement the example DTE control system of  FIGS. 2A and 2B  for checking whether a failure of a component or system of the example aircraft has occurred. 
         FIG. 7  is a flowchart representative of machine readable instructions that may be executed in connection with the flowchart of  FIG. 6  when two actuator control electronics (ACEs) of the example DTE actuation system are inoperable. 
         FIG. 8  is a flowchart representative of machine readable instructions that may be executed in connection with the flowchart of  FIG. 6  when a mechanical failure of a flap actuator has occurred. 
         FIG. 9  is a flowchart representative of machine readable instructions that may be executed in connection with the flowchart of  FIG. 6  when a loss of an aircraft hydraulic system has occurred. 
         FIG. 10  is a flowchart representative of machine readable instructions that may be executed in connection with the flowchart of  FIG. 6  when a malfunction in a hydraulic control module has occurred. 
         FIG. 11  is a flowchart representative of machine readable instructions that may be executed in connection with the flowchart of  FIG. 6  when a failure or loss of one aircraft engine has occurred. 
         FIGS. 12A-12D  are tables of cases that can be utilized in connection with the example flowchart in  FIG. 7 . 
         FIG. 13  is a table of cases that can be utilized in connection with the example flowchart in  FIG. 8 . 
         FIG. 14  is a block diagram of an example processing platform structured to execute the instructions of  FIGS. 6-11  to implement the example DTE control system of  FIGS. 2A and 2B . 
     
    
    
     The figures are not to scale. Instead, the thickness of the layers or regions may be enlarged in the drawings. Although the figures show layers and regions with clean lines and boundaries, some or all of these lines and/or boundaries may be idealized. In reality, the boundaries and/or lines may be unobservable, blended, and/or irregular. In general, the same reference numbers will be used throughout the drawing(s) and accompanying written description to refer to the same or like parts. As used in this patent, stating that any part (e.g., a layer, film, area, region, or plate) is in any way on (e.g., positioned on, located on, disposed on, or formed on, etc.) another part, indicates that the referenced part is either in contact with the other part, or that the referenced part is above the other part with one or more intermediate part(s) located therebetween. As used herein, connection references (e.g., attached, coupled, connected, and joined) may include intermediate members between the elements referenced by the connection reference and/or relative movement between those elements unless otherwise indicated. As such, connection references do not necessarily infer that two elements are directly connected and/or in fixed relation to each other. As used herein, stating that any part is in “contact” with another part is defined to mean that there is no intermediate part between the two parts. 
     Unless specifically stated otherwise, descriptors such as “first,” “second,” “third,” etc. are used herein without imputing or otherwise indicating any meaning of priority, physical order, arrangement in a list, and/or ordering in any way, but are merely used as labels and/or arbitrary names to distinguish elements for ease of understanding the disclosed examples. In some examples, the descriptor “first” may be used to refer to an element in the detailed description, while the same element may be referred to in a claim with a different descriptor such as “second” or “third.” In such instances, it should be understood that such descriptors are used merely for identifying those elements distinctly that might, for example, otherwise share a same name. 
     DETAILED DESCRIPTION 
     Disclosed herein are example distributed trailing edge (DTE) actuation systems and methods for aircraft. With the advances in composite material and manufacturing, most modern aircraft are designed with thinner, lighter wings for performance benefits. The example systems disclosed herein have reduced spatial requirements, which enables the construction of these thinner, lighter wings for the aircraft, which are generally more aerodynamically efficient than thicker, heavier wings. The example systems and methods disclosed herein include independently controllable flap actuators that enhance control of the flap actuation operations. Further, the example systems and methods disclosed herein utilize a redundant architecture that enables continued functionality (or at least partial functionality) in the event of a failure of one or more components or systems. 
     Aircraft typically include one or more flaps (e.g., outboard flaps and/or inboard flaps) located at and/or along the trailing edges of the wings. The flaps can be moved between a stowed position and one or more deployed positions to change the lift generated by the wings. The flaps are typically deployed during takeoff and landing, for example. The flaps are moved via a trailing edge actuation system. Some known trailing edge actuation systems include a series of geared rotary actuators (GRAs) arranged along the wings to move the flaps. The GRAs are coupled via a series of a torque tubes to a power drive unit. When the power drive unit is activated, the power drive unit rotates the series of torque tubes, which drives all of the GRAs simultaneously to move the flaps in unison. 
     These known systems and components require a significant amount of space behind the rear spar of the wing. Thus, the spatial integration of such hardware requires thicker wings, which are generally less efficient than thinner wings. Additionally, these known trailing edge actuation systems require multiple sub-assemblies (e.g., torque tubes, couplings, angle bear boxes, universal joints, and ball screws, etc.), all of which require significant labor installation hours. 
     Disclosed herein are example DTE actuation systems and methods that include independently controllable flap actuators. The example flap actuators can be activated to move the flaps independently or simultaneously between their stowed and deployed positions. In some examples, multiple flap actuators are associated with the same flap. In such instances, the flap actuators can be activated in parallel to move the respective flap. 
     The example flap actuators and associated linkage assemblies disclosed herein utilize less space than known actuators. As such, the examples disclosed herein enable the construction of thinner, lighter wings, which produce more efficient flight. The example flap actuators are also easier to install and, thus, reduce build time of aircraft with high production rates. 
     The example DTE actuation systems and methods disclosed herein include multiple levels of redundancy that improve fault tolerance and enable the continuous operation (or partial operation) of one or more components of the DTE system even if one or more failures occur. In some examples, the flap actuators disclosed herein are hybrid hydraulic-electric actuators that that include an integrated hydraulic powered actuator and electric powered actuator. Each of the flap actuators can be operated in multiple modes including a hydraulic powered mode, an electric powered mode, and a hybrid mode. In the hydraulic powered mode, hydraulic power is used to activate the hydraulic powered actuator to move the flap while the electric powered actuator is inactive, off, or bypassed. In the electric powered mode, electrical power is used to activate the electric powered actuator to move the flap while the hydraulic powered actuator is inactive, off, or bypassed. In the hybrid mode, both the hydraulic powered actuator and the electric powered actuator are activated simultaneously, such that the hydraulic powered actuator and the electric powered actuator act in combination to move the flap. The flap actuator can be switched between the different powered modes if a failure occurs that affects one of the actuators. For example, if the hydraulic powered actuator and/or one of its associated control components fails, the flap actuator can be operated in the electric powered mode in which the electric powered actuator is used. In another example, both the hydraulic powered actuator and the electric powered actuator can be used in combination. For example, if one of the engines fails, the total hydraulic power in the aircraft is reduced. In such an instance, the flap actuator can be switched to its hybrid mode, where the electric powered actuator is activated in combination with the hydraulic powered actuator to compensate for the loss of power. 
     Further, the example DTE actuation systems disclosed herein include a DTE control system with redundant actuator control electronics (ACEs). As a result, if one of the ACEs associated with a flap actuator fails, another ACE can be used to hydraulically and/or or electrically control the hydraulic and electric powered actuators of the flap actuator. Depending on the type and number of failures, the DTE control system can switch the flap actuators between the different modes. 
     As used herein, the term “switch” refers to a mechanical and/or electrical device, component, software implementation, and/or assembly that enables a change in a mode of operation of a device coupled thereto. As used herein, the term “actuator” refers to a device, component, and/or assembly used to convert energy (e.g., electrical energy, fluid/pressure energy, etc.) into motion. Accordingly, the terms “electric powered actuator” and “electric actuator” refer to an actuator that converts electrical power or energy into motion, while the terms “hydraulic powered actuator” and “hydraulic actuator” refer to an actuator that converts hydraulic pressure into motion. 
       FIG. 1  illustrates an example aircraft  100  in which the examples disclosed herein can be implemented. In the illustrated example, the aircraft  100  includes a fuselage  102 , a left wing  104  coupled to the fuselage  102 , and a right wing  106  coupled to the fuselage  102 . The aircraft  100  also includes a first engine  108  coupled to the left wing  104  and a second engine  110  coupled to the right wing  106 . In other examples, the aircraft  100  may have multiple engines coupled to each of the left and right wings  104 ,  106  and/or disposed in other locations on the aircraft  100  (e.g., coupled to the fuselage  102 , coupled to a tail section of the aircraft  100 , etc.). In addition to producing thrust, each of the engines  108 ,  110  drives one or more engine driven pumps for producing pressurized hydraulic fluid for use by one or more systems of the aircraft  100 . Further, each of the engines  108 ,  110  drives one or more generators for producing electrical power for use by one or more electrical motor pumps for producing pressurized hydraulic fluid for use by one or more hydraulic systems of the aircraft  100 . 
     The left and right wings  104 ,  106  may have one or more control surfaces such as high lift devices (e.g., auxiliary airfoils) that are located along the trailing edges of the left and right wings  104 ,  106 . Such high lift devices may be displaced or extended from the trailing edges of the left and right wings  104 ,  106  to change the aerodynamic lift of the aircraft  100  and are typically used during takeoff and landing. For example, in  FIG. 1 , the aircraft  100  includes an outboard left flap  112  (a first flap) and an inboard left flap  114  coupled to the left wing  104 , and an inboard right flap  116  (a third flap) and an outboard right flap  118  (a fourth flap) coupled to the right wing  106 . The flaps  112 - 118  can be moved relative to the trailing edges of the left and right wings  104 ,  106  to change the shape of the left and right wings  104 ,  106  and generate more or less lift. Each of the flaps  112 - 118  is controlled via one or more flap actuators, as disclosed in further detail herein. While in this example the left and right wings  104 ,  106  each include two flaps, in other examples, the left and right wings  104 ,  106  can include more or fewer flaps (e.g., one flap, three flaps, four flaps, etc.). 
     Each of the flaps  112 - 118  is movable between a stowed position and a deployed position (sometimes referred to as a retracted position and an extended position, respectively). In the stowed position, the flaps  112 - 118  are generally aligned with the respective left and right wings  104 ,  106 , as shown in  FIG. 1 . During cruise, for example, the flaps  112 - 118  are typically held in the stowed position, which is more aerodynamic and fuel efficient. In the deployed position, the flaps  112 - 118  are tilted and/or otherwise moved downward relative to the trailing edges of the left and right wings  104 ,  106 . For example, during takeoff and/or landing, the flaps  112 - 118  can be deployed, which increases the chord length of the left and right wings  104 ,  106  to generate more lift. The aircraft  100  includes a cockpit  120  with controls that the pilot(s) can use to control the flaps  112 - 118 . The flaps  112 - 118  can also be moved to any position between the stowed position and the deployed position (e.g., one or more deployed positions between the stowed position and a fully or maximum deployed position). 
       FIG. 2A  illustrates an example distributed trailing edge (DTE) actuation system  200  constructed in accordance with the teachings of this disclosure. The example DTE actuation system  200  is implemented in connection with the aircraft  100  ( FIG. 1 ) for controlling movement (e.g., extending or retracting) of the flaps  112 - 118 . The DTE actuation system  200  is also referred to herein as the system  200 . As disclosed above, each of the flaps  112 - 118  is movable between a stowed position and a deployed position, which affects the lift of the left and right wings  104 ,  106 . The system  200  includes one or more flap actuators for moving the respective flaps  112 - 118 . In particular, as shown in  FIG. 2A , the system  200  includes a first flap actuator  202 , a second flap actuator  204 , a third flap actuator  206 , a fourth flap actuator  208 , a fifth flap actuator  210 , a sixth flap actuator  212 , a seventh flap actuator  214 , and an eighth flap actuator  216 . In some examples, the flap actuators  202 - 216  are rotary actuators (which may be referred to herein as rotary flap actuators). In this example, each of the flaps  112 - 118  is controlled by two of the flap actuators  202 - 216 . The first and second flap actuators  202 ,  204  are outboard and inboard flap actuators coupled to the left wing  104  for controlling movement of the outboard left flap  112 . The third and fourth flap actuators  206 ,  208  are outboard and inboard flap actuators coupled to the left wing  104  for controlling movement of the inboard left flap  114 . The fifth and sixth flap actuators  210 ,  212  are inboard and outboard flap actuators coupled to the right wing  106  for controlling movement of the inboard right flap  116 . The seventh and eighth flap actuators  214 ,  216  are inboard and outboard flap actuators coupled to the right wing  106  for controlling movement of the outboard right flap  118 . The flap actuators  202 - 216  can be operated in pairs to move the respective flaps  112 - 118 . For example, the first and second flap actuators  202 ,  204  can be activated in unison to move the outboard left flap  112  between the stowed position and the deployed position. The flap actuators  202 - 216  can be operated to move the respective flaps  112 - 118  independently of each other or simultaneously. At cruise, the aircraft performance is enhanced by independently positioning the inboard and outboard flaps. Thus, examples disclosed herein enable the TEVC (Trailing Edge Variable Camber) function. While in this example the system  200  includes eight flap actuators, in other examples, the system  200  can include more or fewer flap actuators. Further, each of the flaps  112 - 118  can be activated by more or fewer flap actuators (e.g., one flap actuator, three flap actuators, etc.). 
     In the illustrated example, the system  200  includes a DTE control system  218  for controlling the flap actuators  202 - 216 . Unlike known systems that utilize a series of torque tubes to activate all of the actuators simultaneously, the DTE control system  218  can independently control each of the flap actuators  202 - 216 . In other words, each of the flap actuators  202 - 216  can be operated independently of the other flap actuators. The DTE control system  218  controls the flap actuators  202 - 218  based on commands from a pilot inceptor  220  (e.g., a flap lever) located in the cockpit  120 . The DTE control system  218  determines the position of the pilot inceptor  220  and activates the flap actuators  202 - 216  accordingly. This type of system is considered a fly-by-wire control system. 
     In the example system  200 , each of the flap actuators  202 - 216  is a hybrid hydraulic-electric actuator that includes a hydraulic powered actuator and an electric powered actuator (which may also be referred to as a hydraulic actuator portion and an electric actuator portion, respectively). The DTE control system  218  can operate the flap actuators  202 - 216  in different modes. In this example, the DTE control system  218  can operate the flap actuators  202 - 216  in a first mode, referred to herein as a normal mode or hydraulic powered mode, a second mode, referred to herein as an alternate mode or electric powered mode, and a third mode, referred to herein as a hybrid mode. In the hydraulic powered mode, the DTE control system  218  controls each of the flap actuators  202 - 216  using hydraulic power to operate their hydraulic powered actuators. In the electric powered mode, the DTE control system  218  controls each of the flap actuators  202 - 216  using electrical power to operate their electric powered actuators. In the hybrid mode, the DTE control system  218  controls the flap actuators  202 - 216  using a combination of both their hydraulic powered actuators and their electric powered actuators. An example of a hydraulic-electric actuator is disclosed in further detail herein in connection with  FIGS. 4A-4C and 5 . 
     In the illustrated example, the DTE control system  218  includes actuator control electronics (ACEs) for controlling the flap actuators  202 - 216  in their hydraulic powered mode, electric powered mode, and hybrid mode. In this example, the DTE control system  218  includes a first ACE  222 , a second ACE  224 , a third ACE  226 , and a fourth ACE  228 . The ACEs  222 - 228  control the hydraulic powered actuators and electric powered actuators of certain ones of the flap actuators  202 - 216 , as disclosed in further detail herein. The ACEs  222 - 228  provide redundant control of the flap actuators  202 - 216 . The ACEs  222 - 228  detect a position of the pilot inceptor  220  and command remote electronics units (REUs) (an example of which is shown in  FIGS. 4A, 4B and 4C ) and/or electric motor control units (EMCUs) (an example operation of which is disclosed in connection with  FIG. 8 ) for controlling the flap actuators  202 - 216  based on the detected position. For example, if a pilot moves the pilot inceptor  220  to a position corresponding to a 15° deployment, the ACEs  222 - 228  activate the flap actuators  202 - 216  to move the flaps  212 - 218  to their 15° position. 
       FIG. 2A  shows the components of the DTE control system  218  for controlling the flap actuators  202 - 216  using hydraulic power, and  FIG. 2B  shows the components of the DTE control system  218  for controlling the flap actuators  202 - 216  using electrical power. Referring first to  FIG. 2A , the aircraft  100  ( FIG. 1 ) includes an aircraft hydraulic system  230 . The aircraft hydraulic system  230  provides pressurized hydraulic fluid to various systems of the aircraft  100 . The aircraft hydraulic system  230  can include one or more pumps driven by each of the engines  108 ,  110  ( FIG. 1 ). The aircraft hydraulic system  230  is fluidly connected (e.g., via hydraulic lines or tubes) to each of the hydraulic powered actuators of the flap actuators  202 - 216 . The DTE control system  218  can control the hydraulic powered actuators of the flap actuators  202 - 216  by controlling the flow of pressurized hydraulic fluid into and out of the hydraulic powered actuators. In the illustrated example, each of the hydraulic powered actuators of the flap actuators  202 - 216  is controllable by one of two remote electronics units that are controlled by the ACEs  222 - 228 . 
     In the illustrated example, the DTE control system  218  includes remote electronics units (REUs). In the hydraulic powered mode and the hybrid mode, the REUs can control the hydraulic powered actuators of the flap actuators  202 - 216  to move the respective flaps  112 - 118 . In particular, the REUs receive commands from the ACEs  222 - 228  and convert the commands into control signals for activating the hydraulic powered actuators of the flap actuators  202 - 216 . In the illustrated example, the DTE control system  218  includes a first REU  232 , a second REU  234 , a third REU  236 , a fourth REU  238 , a fifth REU  240 , a sixth REU  242 , a seventh REU  244 , and an eighth REU  246 . The first REU  232  and the eighth REU  246  are controlled by the first ACE  222 . The first REU  232  controls the hydraulic powered actuators of the first and second flap actuators  202 ,  204  based on commands from the first ACE  222 , and the eighth REU  246  controls the hydraulic powered actuators of the seventh and eighth flap actuators  214 ,  216  based on commands from the first ACE  222 . The second REU  234  and the seventh REU  244  are controlled by the second ACE  224 . The second REU  234  controls the hydraulic powered actuators of the first and second flap actuators  202 ,  204  based on commands from the second ACE  224 , and the seventh REU  244  controls the hydraulic powered actuators of the seventh and eighth flap actuators  214 ,  216  based on commands from the second ACE  224 . Thus, the first and second ACEs  222 ,  224  are redundant, the first and second REUs  232 ,  234  are redundant, and the seventh and eighth REUs  244 ,  246  are redundant. If one of the first or second ACEs  222 ,  224  and/or their associated REUs  232 ,  234 ,  244 ,  246  fails and/or otherwise becomes inoperable, the other ACE and its REUs can continue to operate the first, second, seventh, and eighth flap actuators  202 ,  204 ,  214 ,  216  to move the outboard left and right flaps  112 ,  118 . For example, the first REU  232  or the second REU  234  can control the hydraulic powered actuator of the first flap actuator  202  (based on commands from the first and second ACEs  222 ,  224 , respectively). If one of these two REUs fails and/or otherwise becomes inoperable, the other REU can control the hydraulic powered actuator of the first flap actuator  202 . The first REU  232  or the second REU  234  can also control the hydraulic powered actuator of the second flap actuator  204  (based on commands from the first and second ACEs  222 ,  224 , respectively). Similarly, the seventh REU  244  or the eighth REU  246  can control the hydraulic powered actuator of the seventh flap actuator  214  (based on commands from the second and first ACEs  224 ,  222 , respectively). If one of these two REUs fails and/or otherwise becomes inoperable, the other REU can control the hydraulic powered actuator of the seventh flap actuator  214 . The seventh REU  244  or the eighth REU  246  can also control the hydraulic powered actuator of the eighth flap actuator  216  (based on commands from the second and first ACEs  224 ,  222 , respectively). Therefore, the hydraulic powered actuator in DTE control system  218  is controlled by redundancy channels such that if one of the two REU fails, the remaining REU (channel) can still control hydraulic powered actuator of the flap actuator. 
     Similarly, the third and fourth ACEs  226 ,  228  control the hydraulic powered actuators of the third, fourth, fifth, and sixth flap actuators  206 - 212  in a redundant fashion. The third REU  236  and the sixth REU  242  are controlled by the third ACE  226 . The third REU  236  controls the hydraulic powered actuators of the third and fourth flap actuators  206 ,  208  based on commands from the third ACE  226 , and the sixth REU  242  controls the hydraulic powered actuators of the fifth and sixth flap actuators  210 ,  212  based on commands from the third ACE  226 . The fourth REU  238  and the fifth REU  240  are controlled by the fourth ACE  228 . The fourth REU  238  controls the hydraulic powered actuators of the third and fourth flap actuators  206 ,  208  based on commands from the fourth ACE  228 , and the fifth REU  240  controls the hydraulic powered actuators of the fifth and sixth flap actuators  210 ,  212  based on commands from the fourth ACE  228 . Thus, the third and fourth ACEs  226 ,  228  are redundant, the third and fourth REUs  236 ,  238  are redundant, and the fifth and sixth REUs  240 ,  242  are redundant. If one of the third or fourth ACEs  226 ,  228  and/or their associated REUs  236 - 242  fails and/or otherwise becomes inoperable, the other ACE and its REUs can continue to operate the third, fourth, fifth, and sixth flap actuators  206 - 212 . For example, the third REU  236  or the fourth REU  238  can control the hydraulic powered actuator of the third flap actuator  206  (based on commands from the third and fourth ACEs  226 ,  228 , respectively). If one of these two REUs fails and/or otherwise becomes inoperable, the other REU can control the hydraulic powered actuator of the third flap actuator  236 . The third REU  236  or the fourth REU  238  can also control the hydraulic powered actuator of the fourth flap actuator  208  (based on commands from the third and fourth ACEs  226 ,  228 , respectively). Similarly, the fifth REU  240  or the sixth REU  242  can control the hydraulic powered actuator of the fifth flap actuator  210  (based on commands from the fourth and third ACEs  228 ,  226 , respectively). If one of these two REUs fails and/or otherwise becomes inoperable, the other REU can control the hydraulic powered actuator of the fifth flap actuator  210 . The fifth REU  240  or the sixth REU  242  can also control the hydraulic powered actuator of the sixth flap actuator  212  (based on commands from the fourth and third ACEs  228 ,  226 , respectively). Therefore, the hydraulic powered actuator in DTE control system  218  is controlled by redundancy channels such that if one of the two REU fails, the remaining REU (channel) can still control hydraulic powered actuator of the flap actuator. 
     Turning to  FIG. 2B , the DTE control system  218  can also control the electric powered actuators of the flap actuators  202 - 216  to move the flaps  112 - 118 . In particular, in the electric powered mode or the hybrid mode, the ACEs  222 - 228  control the electric powered actuators of certain ones of the flaps actuators  202 - 216  to move the respective flaps  112 - 118 . 
     As shown in  FIG. 2B , the aircraft  100  ( FIG. 1 ) includes an aircraft electrical system  248 . The ACEs  222 - 228  control the supply of electrical power to the electric powered actuators of the flap actuators  202 - 216 . In particular, the ACEs  222 - 228  receive pilot inceptor position and command one or more electric motor control units (disclosed in further detail herein) based on the received pilot inceptor position. The electric motor control units control the electric powered actuators to actuate the respective flap actuators  202 - 216 . In this manner, the ACEs  222 - 228  control the electric powered actuators in the electric powered mode and the hybrid mode. In the illustrated example, the first ACE  222  controls the electric powered actuators of the first and eighth flap actuators  202 ,  216 , the second ACE  224  controls the electric powered actuators of the third and sixth flap actuators  206 ,  212 , the third ACE  226  control the electric powered actuators of the second and seventh flap actuators  204 ,  214 , and the fourth ACE  228  controls the electric powered actuators of the fourth and fifth flap actuators  208 ,  210 . Therefore, at least one of the electric powered actuators of the flap actuators  202 ,  204 ,  214 ,  216  associated with the outboard left and right flaps  112 ,  118  is controlled by the second ACE  224 , and at least one of the electric powered actuators of the flap actuators  206 - 212  associated with the inboard left and right flaps  114 ,  116  is controlled by the third ACE  226 . 
     In the illustrated example, the DTE control system  218  includes electric motor control units (EMCUs). Each of the EMCUs controls one or more of the electric powered actuators of the flap actuators  202 - 216 , and each of the EMCUs is controlled by an ACE. The EMCUs receive commands from the ACEs  222 - 228  and convert the commands into control signals for activating the electric powered actuators of the flap actuators  202 - 216 . In the illustrated example, the DTE control system  218  includes a first EMCU  250 , a second EMCU  252 , a third EMCU  254 , and a fourth EMCU  256 . The first EMCU  250  controls the electric powered actuators of the first and eighth flap actuators  202 ,  216  based on commands from the first ACE  222 . The second EMCU  252  controls the electric powered actuators of the third and sixth flap actuators  206 ,  212  based on commands from the second ACE  224 . The third EMCU  254  controls the electric powered actuators of the second and seventh flap actuators  204 ,  214  based on commands from the third ACE  226 . The fourth EMCU  256  controls the electric powered actuators of the fourth and fifth flap actuators  208 ,  210  based on commands from the fourth ACE  228 . 
     In the illustrated example, the DTE control system  218  includes a first switch  258  that is electrically coupled between the aircraft electrical system  248  and the first EMCU  250 . The first switch  258  is controlled by the first ACE  222 . To operate the electric powered actuators of the first and eighth flap actuators  202 ,  216  (e.g., in the electric powered mode and/or the hybrid mode), the first ACE  222  activates the first switch  258  (e.g., to create a closed circuit), which enables the supply of electrical power from the aircraft electrical system  248  to the first EMCU  250 . The first EMCU  250  then activates the electric powered actuators of the first and eighth flap actuators  202 ,  216  (e.g., by controlling the supply of electrical power to the electric powered actuators) based on commands from the first ACE  222 . Similarly, the DTE control system  218  includes a second switch  260  between the aircraft electrical system  248  and the second EMCU  252 , a third switch  262  between the aircraft electrical system  248  and the third EMCU  254 , and a fourth switch  264  between the aircraft electrical system  248  and the fourth EMCU  256 . The second, third, and fourth switches  260 ,  262 ,  264  are similarly controlled by the respective second, third, and fourth ACEs  224 - 228 . 
     As shown in  FIGS. 2A and 2B , the DTE control system includes a failure detector  266 . In some examples, the failure detector  266  determines whether there has been a failure or loss of normal functionality in one or more systems or components of the system  200  and/or other systems or components of the aircraft  100  ( FIG. 1 ). In some examples, the failure detector  266  determines whether there has been a failure based on input from one or more sensor(s)  268 . The sensor(s)  268  can be operatively coupled and/or associated with various components and/or systems. For example, the sensor(s)  268  can include sensors in the flap actuators  202 - 216  for detecting failure of the flap actuators  202 - 216 , a sensor in the aircraft hydraulic system  230  for detecting failure of loss of hydraulic power, etc. Based on whether there has been a failure, and/or what type of failure, the ACEs  222 - 228  can switch between operating the flap actuators  202 - 216  in the hydraulic powered mode, the electric powered mode, and the hybrid mode. 
     As shown in  FIGS. 2A and 2B , the DTE control system  218  includes an alert generator  270 . In some examples, the alert generator  270  generates an alert in a flight deck  272  (e.g., a screen or monitor, a control panel, etc.) in the cockpit  120  to indicate to the pilot that certain ones of the flaps  112 - 118  are inoperable. The pilot can then operate the aircraft  100  according to a non-normal procedure to compensate for the lack of certain ones of the flaps  112 - 118 . For example, if one or more of the flap actuators associated with the outboard left and right flaps  112 ,  118  are inoperable, the DTE control system  218  may disable the flap actuators  202 ,  204 ,  214 ,  216  associated with the outboard left and right flaps  112 ,  118 , and lock the outboard left and right flaps  112 ,  118  in place (e.g., via no-backs). In such an instance, the flap actuators  206 - 212  may still be used to move the inboard left and right flaps  114 ,  116 . Therefore, the pilot can still use the inboard left and right flaps  114 ,  116  to control the aircraft  100  ( FIG. 1 ). 
     The ACEs  222 - 228 , the REUs  232 - 246 , the EMCUs  250 - 256 , the switches  258 - 264 , the failure detector  266 , and/or the alert generator  270 , can be implemented by separate devices or implemented in combination by one or more devices, such as the processor  1412  disclosed in connection with  FIG. 14 . Before describing the types of failures and modes of operation, a description of the flap actuators and actuator linkage assemblies is described in connection with  FIGS. 3A, 3B, 4A-4C, and 5 . 
       FIGS. 3A and 3B  are cross-sectional views of the left wing  104  showing the first flap actuator  202  and an example linkage assembly  300  associated with the first flap actuator  202  for moving the outboard left flap  112 .  FIG. 3A  shows the outboard left flap  112  in the stowed position and  FIG. 3B  shows the outboard flap in the deployed position. The first flap actuator  202  can be activated to move the outboard left flap  112  between the stowed position and the deployed position via the linkage assembly  300 . Each of the other flap actuators  204 - 216  ( FIGS. 2A and 2B ) includes a similar linkage assembly and operates in a similar manner. To avoid redundancy, the linkage assembly  300  is only described in connection with the first flap actuator  202  of the outboard left flap  112 . However, it is understood that other flap actuators  204 - 216  can include similar linkage assemblies for moving the respective flaps in a similar manner. 
     In the illustrated example, the first flap actuator  202  is coupled to the left wing  104 . For example, the first flap actuator  202  can be coupled to a support beam in the left wing  104 , such as a rear spar  302  and/or a rib  304  in the left wing  104 . In other examples, the first flap actuator  202  can be coupled to another structure in the left wing  104 . 
     In this example, the first flap actuator  202  is a rotary actuator. As shown in  FIGS. 3A and 3B , the first flap actuator  202  includes a crank arm  306 , sometimes referred to as an output arm. The crank arm  306  is rotatable about an axis (e.g., an axis  502  shown in  FIG. 5 ). The first flap actuator  202  can be activated to rotate the crank arm  306 . In particular, the first flap actuator  202  can be activated to rotate the crank arm  306  in a first direction (the clockwise direction in  FIGS. 3A and 3B ) to move the outboard left flap  112  from the stowed position to the deployed position, or activated to rotate the crank arm  306  in a second direction (the counter-clockwise direction in  FIGS. 3A and 3B ) to move the outboard left flap  112  from the deployed position to the stowed position. The crank arm  306  can be driven by the hydraulic powered actuator and/or the electric powered actuator of the first flap actuator  202 . Examples of the hydraulic powered actuator and the electric powered actuator are disclosed in further detail in connection with  FIGS. 4A-4C and 5 . 
     The crank arm  306  is coupled to the outboard left flap  112  via the linkage assembly  300 . The linkage assembly  300  includes a plurality of links (which may be referred to as arms, rods, cranks, etc.) that couple the crank arm  306  to the outboard left flap  112  such that movement of the crank arm  306  causes movement of the outboard left flap  112 . In the illustrated example, the linkage assembly  300  includes a push rod  308 , a first crank  310 , a second crank  312 , a third crank  314 , and a support arm  316 . In the illustrated example, the push rod  308  is coupled between the crank arm  306  and the first crank  310 . In particular, one end of the push rod  308  is pivotably coupled to the crank arm  306  at a first pivot  318 , and the opposite end of the push rod  308  is pivotably coupled to an end of the first crank  310  and a flap horn arm  330  at a second pivot  320 . 
     As shown in  FIGS. 3A and 3B , the first crank  310  is pivotably coupled to the support arm  316  at a third pivot  322 . The support arm  316  is pivotably coupled to the left wing  104  at a fourth pivot  324 . The support arm  316  extends aft from the left wing  104 . The second crank  312  is coupled between the left wing  104  and the first crank  310 . In particular, one end of the second crank  312  is pivotably coupled to the left wing  104  at a fifth pivot  326 , and the opposite end of the second crank  312  is pivotably coupled to the first crank  310  at a sixth pivot  328 . The sixth pivot  328  is between the second and third pivots  320 ,  322 . The push rod  308  and the first crank  310  are also pivotably coupled at the second pivot  320  to the flap horn arm  330  of the outboard left flap  112 . 
     In the illustrated example, the third crank  314  is coupled between an end of the support arm  316  and the flap horn arm  330  on the outboard left flap  112 . In particular, one end of the third crank  314  is pivotably coupled to the support arm  316  at a seventh pivot  332 , and the opposite end of the third crank  314  is pivotably coupled to the flap horn arm  330  at an eighth pivot  334 . 
     To move the outboard left flap  112  from the stowed position in  FIG. 3A  to the deployed position in  FIG. 3B , for example, the first flap actuator  202  is activated to rotate the crank arm  306  in the clockwise direction in  FIGS. 3A and 3B . As the crank arm  306  rotates, the crank arm  306  pushes the push rod  308  to the right in  FIGS. 3A and 3B . This causes the first crank  310  to pivot about the third pivot  322  in the clockwise direction of  FIGS. 3A and 3B . The second crank  312  pivots about the fifth pivot  326  in the counter-clockwise direction in  FIGS. 3A and 3B . The first crank  310  pushes the support arm  316  downward, such that the support arm  316  pivots about the fourth pivot  324 . The push rod  308  also pushes the flap horn arm  330  to the right in  FIGS. 3A and 3B  and, thus, moves the outboard left flap  112  downward, as shown in  FIG. 3B . 
     The first flap actuator  202  can be stopped or deactivated when the outboard left flap  112  reaches the deployed position. The first flap actuator  202  can be activated to rotate the crank arm  306  in the opposite direction (the counter-clockwise direction in  FIGS. 3A and 3B ) to move the outboard left flap  112  back to the stowed position. The first flap actuator  202  can be activated to move the outboard left flap  112  to any position between the stowed position shown in  FIG. 3A  and the deployed position shown in  FIG. 3B . 
     In some examples, the linkage assembly  300  is disposed at least partially within a flap support fairing  336  coupled to and movable with the outboard left flap  112 . The flap support fairing  336  provides an aerodynamic covering for the linkage assembly  300 . 
     The example first flap actuator  202  and the example linkage assembly  300  are more compact than known actuators and linkage assemblies. Further, the example first flap actuator  202  and the example linkage assembly  300  do not require torque tubes or transmissions between the torque tubes along the rear spar  302  as in known assemblies. As a result, less space is utilized behind the rear spar  302 . As such, the left wing  104  is be constructed thinner, which produces more efficient flight. 
       FIG. 4A  is a partial cross-sectional view of the example first flap actuator  202  and a schematic diagram of associated control components. Each of the other flap actuators  204 - 216  ( FIGS. 2A and 2B ) is substantially the same as the first flap actuator  202 . Therefore, any of the structures and/or functions disclosed in connection with the first flap actuator  202  can likewise apply to the other flap actuators  204 - 216 . 
     As disclosed above, the first flap actuator  202  is a hydraulic-electric actuator. The first flap actuator  202  includes a hydraulic powered actuator  400  (which may also be referred to as a hydraulic actuator) shown in  FIGS. 4A-4C  and an electric powered actuator  500  (which may also be referred to as an electric actuator) shown in  FIG. 5 . As shown in  FIGS. 4A-4C , the first flap actuator  202  includes a hydraulic control module (HCM)  404  to control the operation of the hydraulic powered actuator  400 . The hydraulic powered actuator  400  ( FIGS. 4A-4C ) is coupled to the crank arm  306  and can be actuated to rotate the crank arm  306  to move the outboard left flap  112  ( FIG. 1 ), and the electric powered actuator  500  ( FIG. 5 ) is coupled to the crank arm  306  and can be activated to rotate the crank arm  306  to move the outboard left flap  112 . The first flap actuator  202  is operable in the hydraulic (normal) powered mode in which the hydraulic powered actuator  400  is activated to move the outboard left flap  112 , the electric (alternate) powered mode in which the electric powered actuator  500  is activated to move the outboard left flap  112 , and the hybrid mode in which the hydraulic powered actuator  400  and the electric powered actuator  500  are activated simultaneously to move the outboard left flap  112 . 
     Referring to  FIG. 4A , the hydraulic powered actuator  400  includes a dual piston arrangement. In some examples, using such a dual tandem or multiple tandem pistons arrangement generates adequate output forces for moving the crank arm  306  and minimizes the actuator diameter. In the illustrated example, the hydraulic powered actuator  400  includes a first housing  406  (e.g., a cylinder) and a second housing  408  coupled to the first housing  406 . The hydraulic powered actuator  400  includes an integrated piston and rack assembly  410  (referred to herein as the piston assembly  410 ). The piston assembly  410  includes a first piston  412  disposed in the first housing  406  and a second piston  414  disposed in the second housing  408 . The piston assembly  410  also includes a piston rod  416  that couples the first and second pistons  412 ,  414  such that the first and second pistons  412 ,  414  move together (in tandem). As shown in  FIG. 4A , the first piston  412  divides the first housing  406  into a first chamber  418  and a second chamber  420 . Similarly, the second piston  414  divides the second housing  408  into a first chamber  422  and a second chamber  424 . When there is higher pressure in the first chambers  418 ,  422 , the first and second pistons  412 ,  414  are moved to the right in  FIG. 4A , and when there is higher pressure in the second chambers  420 ,  424 , the first and second pistons  412 ,  414  are moved to the left in  FIG. 4A . In some examples, one or more seals are disposed between the first and second pistons  412 ,  414  and the respective housings  406 ,  408  to prevent leakage of hydraulic fluid between the chambers. 
     In the illustrated example, the first piston  412  includes a first sub-piston  426  and a second sub-piston  428  spaced apart from the first sub-piston  426 . The hydraulic powered actuator  400  also includes a rack  430  with teeth. In the illustrated example, the rack  430  is part of the piston assembly  410  and coupled between the first sub-piston  426  and the second sub-piston  428 . In other examples, the rack  430  can be disposed in another location (e.g., on the piston assembly  410  outside of the first and second housings  406 ,  408 ). In the illustrated example, the hydraulic powered actuator  400  includes a pinion gear  432 . The pinion gear  432  is at least partially disposed in the first housing  406  and engaged (meshed) with the rack  430 . The pinion gear  432  is coupled to the crank arm  306  such that linear movement of the rack  430  causes rotation of the pinion gear  432  and, thus, rotation of the crank arm  306 . When the first piston  412  is moved to the right in  FIG. 4A  (e.g., by pressurizing the first chambers  418 ,  422 ), the crank arm  306  is rotated in the counter-clockwise direction, and when the first piston  412  is moved to the left in  FIG. 4A  (e.g., by pressurizing the second chambers  420 ,  424 ), the crank arm  306  is rotated in the clockwise direction. While in this example the hydraulic powered actuator  400  utilizes a dual piston arrangement, in other examples, the hydraulic powered actuator  400  may only include one piston (e.g., only the first housing  406  and the first piston  412 ). 
     In some examples, the piston assembly  410  includes an anti-rotation device to prevent the piston assembly  410  from rotating in the first and second housings  406 ,  408  to maintain engagement between the pinion gear  432  and the rack  430 . For example, as shown in  FIG. 4A , the piston assembly  410  includes first and second tabs  434 ,  436  (the second tab  436  is shown in  FIG. 5 ). In this example, the first and second tabs  434 ,  436  extend from the rack  430  toward an inner wall of the first housing  406 . The first and second tabs  434 ,  436  are disposed on opposite sides of a ridge  438  extending from an inner surface of the first housing  406 . The first and second tabs  434 ,  436  slide or move along the ridge  438  as the piston assembly  410  moves. Should the piston assembly  410  start to rotate, one of the tabs  434 ,  436  engages the ridge  438  to prevent the piston assembly  410  from rotating. The anti-rotation feature prevents the rack teeth from disconnecting from the pinion teeth. 
     In the illustrated example, the hydraulic powered actuator  400  includes the HCM  404 . The HCM  404  controls the flow of pressurized fluid into or out of the chambers  418 - 424  to control the movement of the first and second pistons  412 ,  414 , and thereby control the movement of the crank arm  306 . The HCM  404  is redundantly controlled by the first or the second REUs  232 ,  234 . For example, in  FIG. 2A , the first REU  232  has a primary role to control the first flap actuator  202 . The second REU  234  has primary role is to control the second actuator  204 . The first REU  232  has a secondary role to control the second flap actuator  204  when the second REU  234  fails. Similarly, the second REU  234  has a secondary role to control the first flap actuator  202  when the first REU  232  fails. This method allows airplane dispatch with one failed REU. The first ACE  222  sends commands to the first REU  232  to the first flap actuator  202 . The first REU  232  interprets the commands and controls electrical components of the HCM  404  of the first flap actuator  202  (e.g., to achieve the commanded position). If the first REU  232  fails, the second REU  234  can interpret commands from the second ACE  224  and control the electrical components of the HCM  404  of the first flap actuator  202 . Thus, the first and second ACEs  222 ,  224  and the first and second REUs  232 ,  234  provide redundant electrical control for the first flap actuator  202 . The first and second ACEs  222 ,  224  and the first and second REUs  232 ,  234  similarly provide redundant electrical control for the second flap actuator  204 . 
     As shown in  FIG. 4A , the HCM  404  is fluidly coupled to the aircraft hydraulic system  230 . In particular, the HCM  404  is fluidly coupled to a supply line  440  and a return line  442  of the aircraft hydraulic system  230 . The supply line  440  provides high pressure hydraulic fluid from the aircraft hydraulic system  230 , and the return line  442  returns low pressure hydraulic fluid to the aircraft hydraulic system  230 . In some examples, as shown in  FIG. 4A , the HCM  404  includes a fluid filter  444  coupled to the supply line  440  to filter particles, debris, and/or contaminants from the hydraulic fluid before entering the HCM  404 . In some examples, the HCM  404  includes anti-cavitation valves to prevent aiding airloads from causing actuator cavitation during flap retraction. 
     In the illustrated example, the HCM  404  includes a first valve  446 , a second valve  448 , and a third valve  450 . In this example, the first valve  446  is a Solenoid Operating Valve (SOV), referred to herein as the SOV  446 , the second valve  448  is a Mode Selector Valve (MSV), referred to herein as the MSV  448 , and the third valve  450  is an Electro-hydraulic Servo-valve (EHSV), referred to herein as the EHSV  450 . As shown in  FIG. 4A , the supply line  440  and the return line  442  are fluidly coupled to the first valve  446 . The SOV  446  is controlled by the first REU  232 . The SOV  446  is operable between a first state  452  and a second state  454 , referred to herein as an OFF state  452  and an ON state  454  (sometimes referred to as valve positions, or ported positions). The SOV  446  is spring loaded to bias to the OFF state  452  (e.g., via a spring). As shown in the callout in  FIG. 4A , the SOV  446  includes a solenoid  456  with a first coil  458  and a second coil  460 . The first and second coils  458 ,  460  are electrically coupled to the first and second REUs  232 ,  234 , respectively, via separate control channels. Thus, the SOV  446  includes redundant electrically controlled coils interfaced with redundant control channels. When either one of the two coils  458 ,  460  is activated, the SOV valve  446  is switched to or maintained in the ON state  454 . Therefore, if one of the two coils  458 ,  460  fails, the other coil can still energize the solenoid of the SOV  446 . For example, during normal operation, the first REU  232  applies electrical power to one of the two or more redundant coils  458 ,  460  to maintain the SOV  446  in the ON state  454 . In this ON state  454 , as shown in  FIG. 4A , the SOV  446  fluidly couples the supply line  440  to a pilot  462  of the MSV  448 . This provides pressure to maintain the MSV  448  in an active state, as disclosed in further detail below. As shown in  FIG. 2A , if one of the ACEs  222 ,  224  and/or their associated REU  232 ,  234  fails and/or otherwise becomes inoperable, the other ACE and its REU can maintain the SOV  446  in the ON state  454  and, thus, maintain the MSV  448  in the active state. If both the first and second REUs  232 ,  234  cease power to the SOV  446  (e.g., via a command or because of a failure), the SOV  446  switches to the OFF state  452 , which cuts off pressure to the pilot  462  of the MSV  448  and vents the pressure at the pilot  462  to the return line  442 . Therefore, when the SOV  446  is supplied with an electrical signal from at least one of the first REU  232  or the second REU  234 , the SOV  446  is switched to the ON state  454 , and when the SOV  446  is not supplied with the electrical signal from at least one of the first REU  232  or the second REU  234 , the SOV  446  is switched to the OFF state  452 . 
     In the illustrated example, the MSV  448  is fluidly coupled to the supply line  440  and the return line  442  and controls the flow of pressurized hydraulic fluid to the EHSV  450 . The MSV  448  is operable between a two states  464  and  466 , referred to as the bypass state  464  and the active state  466 . In the bypass state  464  the MSV  448  disconnects the supply line  440  and the return line  442  from the EHSV  450 , and fluidly couples the first chambers  418 ,  422  and the second chambers  420 ,  424  to each other. An example of this state is disclosed in further detail in connection with  FIG. 4C . In the active state  466 , which is the state shown in  FIG. 4A , the MSV  448  fluidly couples the supply line  440  and the return line  442  to the EHSV  450 . In this example, the MSV  448  is a piloted valve. The MSV  448  is biased to the bypass state  464  (e.g., via a mechanical spring). If pressure is supplied to the pilot  462 , such as when the SOV  446  is in the ON state  454 , the MSV  448  is switched to and/or otherwise held in the active state  466 . If pressure is ceased at the pilot  462 , such as when the SOV  446  is in the OFF state  452 , the MSV  448  is switched to and/or otherwise held the bypass state  464 . Therefore, as long as either the first REU  232  or the second REU  234  applies energy to the channels  458 ,  460 , the MSV  448  remains in the active state  466 . 
     In the illustrated example, the hydraulic powered actuator  400  includes a first control fluid line  468  fluidly coupled to the first chambers  418 ,  422 , and a second control fluid line  470  fluidly coupled to the second chambers  420 ,  424 . As shown in  FIG. 4A , the EHSV  450  is multi orifice flow-control component with the first and second control fluid line  468 ,  470 , and two control ports  472  and  476 . When the EHSV  450  is in the first control port  472 , it meters the supply fluid (from the supply line  440 ) to the first control fluid line  468  and opens the second control fluid line  470  to return (to the return line  442 ). When the EHSV  450  is in the second control port  476 , it meters the supply fluid (from the supply line  44 ) to the second control fluid line  470  and opens the first control fluid line  468  to return (to the return line  442 ). When the EHSV  450  in a middle port  474  (which may be referred to as the normal state), the pressure in the first and second control fluid lines  468 ,  470  are equal. 
     The EHSV  450  has two or more redundant coils. In particular, as shown in the callout in  FIG. 4A , the EHSV  450  has a solenoid  477  with a first coil  478  and a second coil  480 . The first coil  478  is electrically coupled to the first REU  232  and the second coil  480  is electrically coupled to the second REU  234 . Thus, the EHSV  450  includes redundant electrically controlled coils interfaced with redundant control channels. Therefore, either the first or the second REUs  232 ,  234  can control the state of the EHSV  450 . As such, if one of the ACEs  222 ,  224  and/or its associated REU  232 ,  234  fails, the other ACE and its REU can continue to operate the EHSV  450  to control the hydraulic powered actuator  400 . If both the first and second REUs  232 ,  234  cease power to the EHSV  450  (e.g., via a command or because of a failure), the EHSV  450  switches to the middle port  474 . 
     When the outboard left flap  112  reaches the desired position (e.g., the stowed position or any flap commanded position), the first REU  232  controls the EHSV  450  to the middle port  474  shown in  FIG. 4A , thereby maintaining the outboard left flap  112  at the desired position. When the EHSV  450  is in the middle port  474 , the pressures in the first and second control fluid lines  468 ,  478  are approximately equal. As such, the crank arm  306  is held in its current position and, thus, the outboard left flap  112  is held in its current position for short term. For long term (e.g., to compensate for internal hydraulic leakages either at pistons or at others), the outboard left flap  112  is held in its current position by a no-back  544  in  FIG. 5 . 
     In some examples, the first or second REUs  232 ,  234  control the movement of the outboard left flap  112  based on feedback from a position sensor  482  shown in  FIG. 5 . In some examples, the position sensor  482  measures or detects the position of the crank arm  306 , which corresponds to a position of the outboard left flap  112 . For example, while the hydraulic powered actuator  400  is moving the outboard left flap  112 , the first and/or second REUs  232 ,  234  monitor the position of the crank arm  306  based on feedback from the position sensor  482 . When the crank arm  306  reaches a position corresponding to the desired position of the outboard left flap  112 , the first and/or second REUs  232 ,  234  commands the EHSV  450  to the middle port  474 . The data (measurements) of the position sensor  482  from two actuators on a flap are processed by the ACEs to ensure the positions of two actuators do not result in an unacceptable force fight threshold which may cause a fatigue damage. Also, data (measurements) the position sensors from two flap pairs (e.g., left inboard flap and right inboard flap) are processed by the ACEs to ensure the positions of two flap pairs are synchronized (e.g., mismatch is small and does not introduce unwanted airplane rolling moment). 
       FIG. 4B  shows an example in which the HCM  404  controls the hydraulic powered actuator  400  to move the outboard left flap  112  ( FIG. 1 ) in the opposite direction such as, for example, if the first REU  232  or second REU  234  is commanded to deploy the outboard left flap  112  (e.g., move the outboard left flap  112  to the deploy position ( FIG. 3B )). The EHSV  450  is controlled to the second control port  476 . This causes the crank arm  306  to rotate in the clockwise direction in  FIG. 4B , thereby moving the outboard left flap  112  toward the deployed position. As such, the EHSV  450  is operable between a first state (the first control port  472 ) to move the crank arm  306  in a first direction and a second state (the second control port  476 ) to move the crank arm  306  in a second direction. 
     As shown in  FIG. 4B , the crank arm  306  has rotated an angle β relative to the position shown in  FIG. 4A . The angle β can be controlled to be any angle. In some examples, the angle β represents the total angle to move the outboard left flap  112  ( FIG. 1 ) between the stowed position ( FIG. 3A ) and the maximum deployed position ( FIG. 3B ). 
     As shown in  FIGS. 4A and 4B , a cavity or chamber  484  is formed between the first and second sub-pistons  426 ,  428  of the first piston  412 . The chamber  484  is filled with hydraulic fluid and connected to a hydraulic return system (e.g., an exhaust line  486  that fluidly couples the chamber  484  to the return line  442 ). It also serves as a lubricant for the rack and pinion, and the bearing  516  and  518  (shown in  FIG. 5 ). 
       FIG. 4C  shows an example of the hydraulic powered actuator  400  in which the SOV and MSV  446 ,  448  are controlled to their first states  452 ,  464 , which is referred to as a bypass mode. In  FIG. 4C  the EHSV  450  is in second control port  476 , because the EHSV  450  may have failed in this position (although the EHSV  450  may fail in any of the three ports/states). As disclosed above, in some instances, it may be desired to disable use of the hydraulic powered actuator  400 . This may occur, for example, if there is a failure in the hydraulic powered actuator  400  or loss of the aircraft hydraulic system  230 . In such an instance, it may be desirable to control the hydraulic powered actuator  400  into a bypass mode, such that the electric powered actuator  500  ( FIG. 5 ) can control the crank arm  306  to move the outboard left flap  112  ( FIG. 1 ). For example, if the first and second ACEs  222 ,  224  fail and/or otherwise become inoperable, the first and second REUs  232 ,  234  cease power to the solenoid of the SOV  446 . As a result, the SOV  446  operates to the OFF state  452 , as shown in  FIG. 4C . In the OFF state  452 , the SOV  446  vents the pilot  462  of the MSV  448  to the return line  442 . As a result, the MSV  448  operates to the bypass state  464 , which cuts off the supply of pressurized fluid to the EHSV  450 . Therefore, the SOV  446  is operable between the OFF state  452  in which SOV  446  (via the MSV  448 ) shuts off the supply of pressurized hydraulic fluid to the EHSV  450 , and the ON state  454  in which the SOV  446  enables the pressurized hydraulic fluid to be supplied to the EHSV  450 . When the MSV  448  is in its bypass state  464 , the MSV  448  fluidly couples the first and second control fluid lines  468 ,  470 . Thus, the first chambers  418 ,  422  and the second chamber  420 ,  424  are fluidly coupled. This enables the piston assembly  410  to be moved freely and be back-driven by the electric powered actuator. The crank arm  306  can then be controlled via the electric powered actuator  500  ( FIG. 5 ) to move the outboard left flap  112 . Similarly, if the failure detector  266  determines there has been a failure of a mechanical portion of the hydraulic powered actuator  400  and/or there has been a loss of hydraulic power, the first and second ACEs  222 ,  224  can command the first and second REUs  232 ,  234  to switch the SOV  446  to the OFF state  452  (e.g., by ceasing power to the solenoid  456 ) to disable the hydraulic powered actuator  400 . 
       FIG. 5  is a cross-sectional view of the first flap actuator  202  taken along line A-A in  FIG. 4C .  FIG. 5  shows the hydraulic powered actuator  400  and the electric powered actuator  500  of the first flap actuator  202  that can be used to move the crank arm  306  to control the position of the outboard left flap  112  ( FIG. 1 ). The crank arm  306  rotates or pivots about an axis  502  shown in  FIG. 5 . 
     As shown in  FIG. 5 , the hydraulic powered actuator  400  is coupled to a support bracket  504  in the left wing  104  ( FIG. 1 ). The support bracket  504  can be mounted to the rear spar  302  ( FIG. 3A ), the rib  304  ( FIG. 3A ), and/or any other structural support in the left wing  104 . In the illustrated example, the first and second housings  406 ,  408  of the hydraulic powered actuator  400  are coupled to the support bracket  504  via one or more threaded fasteners  506  (e.g., bolts). In other examples, the first and second housings  406 ,  408  (and/or another part of the hydraulic powered actuator  400 ) can be coupled to the support bracket  504  using other fastening techniques. The first and second housings  406 ,  408  can be constructed of one more portions coupled together. The portions can be sealed via one or more static seal(s)  508  (e.g., an o-ring) and via one or more shaft seal(s)  514  (e.g., an oil seal) to prevent leakage of the hydraulic fluid. 
     In the illustrated example, the pinion gear  432  of the hydraulic powered actuator  400  is coupled to a shaft  510  (e.g., an axle). The shaft  510  extends through an opening  512  in the support bracket  504  and is coupled to the crank arm  306 . Therefore, the pinion gear  432  is coupled to the crank arm  306  via the shaft  510 . The electric powered actuator  500  is also coupled to the shaft  510 , as disclosed in further detail herein. The pinion gear  432  and the shaft  510  are rotated on the axis  502 . The pinion gear  432 , the shaft  510 , and the crank arm  306  are fixedly coupled and rotate together on the axis  502 . As shown in  FIG. 5 , the shaft  510  extends through the shaft seal  514  (e.g., an oil seal), which prevents leakage of the hydraulic fluid out of the first and second housings  406 ,  408 . In the illustrated example, the shaft  510  is supported by and rotatable on first and second bearings  516 ,  518  (e.g., ball or roller bearings). The first and second bearings  516 ,  518  enable the shaft  510 , to rotate reliably while constraining its rotation on the axis  502 . 
       FIG. 5  shows the ridge  438  on the inner surface of the first housing  406 . The ridge  438  extends between the first and second tabs  434 ,  436  on the piston assembly  410 . The ridge  438  prevents the piston assembly  410  from rotating, so that the rack  430  ( FIG. 4A ) remains aligned and engaged with the pinion gear  432 . 
     In the illustrated example, the electric powered actuator  500  is coupled to the support bracket  504 . In the illustrated example, the hydraulic powered actuator  400  and the electric powered actuator  500  are disposed on opposite sides of the support bracket  504 . In other examples the hydraulic powered actuator  400  and the electric powered actuator  500  can be arranged in other configurations. The hydraulic powered actuator  400  is coupled to a first end of the shaft  510  and the electric powered actuator  500  is coupled to a second end of the shaft  510 . Either or both of the hydraulic powered actuator  400  and the electric powered actuator  500  can be actuated to rotate the shaft  510  and, thus, rotate the crank arm  306 . In the illustrated example, the electric powered actuator  500  includes a housing  520  that is coupled to the support bracket  504  via one or more threaded fasteners  522  (e.g., bolts). In other examples, the housing  520  (and/or another part of the electric powered actuator  500 ) can be coupled to the support bracket  504  using other fastening techniques. In some examples, the housing  520  is constructed of two or more portions coupled together. 
     The electric powered actuator  500  includes an electric motor  524  (e.g., a DC brushless motor) disposed in the housing  520 . The electric motor  524  has a motor output shaft  526  that is rotated when the electric motor  524  is activated. A pinion  528  is coupled to the motor output shaft  526 . The electric motor  524 , the motor output shaft  526 , and the pinion  528  are aligned and rotated along the axis  502 . The motor output shaft  526  and the pinion  528  are coupled via an electric brake  538 . The electric motor  524  and the electric brake  538  can be activated to rotate the pinion  528  in either direction to rotate the crank arm  306 . 
     The motor output shaft  526  can be coupled to the shaft  510  via a reduction gear system. In particular, in the illustrated example of  FIG. 5 , the pinion  528  is coupled to the shaft  510  via a planetary gear system  530 . In other examples, other types of systems and/or speed reducer gearboxes can be implemented. The planetary gear system  530  includes planetary gears  532 , a ring gear  534 , and a carrier  536 . The pinion  528  (which may be considered a sun gear) is engaged (meshed) with the planetary gears  532 . The planetary gears  532  are engaged (meshed) with the ring gear  534 , which is disposed outside of the planetary gears  532 . The ring gear  534  is coupled to the housing  520  and remains stationary. The planetary gears  532  are coupled to the carrier  536 . The carrier  536  is coupled to the shaft  510  and, thus, is coupled to the crank arm  306 . When the electric motor  524  and the electric brake  538  are activated, the pinion  528  rotates the planetary gears  532 , which rotate the carrier  536 , which rotates the shaft  510 , which rotates the crank arm  306 . In this example, the electric motor  524  is a bi-directional electric motor that can drive the pinion  528  in either direction to move the crank arm  306  in either direction. 
     In the illustrated example, the electric powered actuator  500  includes the electric brake  538 . In this example, the electric brake  538  transmits the power of the motor output shaft  526  to the pinion  528  when the electric brake  538  is electrically activated. The electric brake  538  is deactivated (e.g., OFF) when hydraulic powered actuator  400  is in ACTIVE mode and electric powered actuator  500  is OFF. When the electric electric brake  538  is deactivated (e.g., OFF), the pinion  528  and the motor output shaft  526  are disenagaged. The electric brake  538  is activated (e.g., ON) when the hydraulic powered actuator  400  is in BYPASS mode and the electric powered actuator  500  is ON. When the electric brake  538  is activated (e.g., ON), the pinion  528  and the motor output shaft  526  are engaged. In HYBRID mode, the electric brake  538  is activated (e.g., ON) (and, thus, the pinion  528  and the motor output shaft  526  are engaged). 
     As disclosed herein, the first flap actuator  202  can be operated in the hydraulic powered mode in which only the hydraulic powered actuator  400  is activated (e.g., in active mode) to move the outboard left flap  112  ( FIG. 1 ) and the electric powered actuator  500  is OFF, the electric powered mode in which only the electric powered actuator  500  is activated to move the outboard left flap  112  while the hydraulic powered actuator  400  is in bypassed mode, and the hybrid mode in which both the hydraulic powered actuator  400  and the electric powered actuator  500  are activated (e.g., in active mode) and simultaneously actuate the outboard left flap  112 . When the hydraulic powered actuator  400  is in active mode, the shaft  510  also rotates the carrier  536 , which rotates the planetary gear system  530 . Assuming the first flap actuator  202  is operated in the electric mode, the electric powered actuator  500  is in active mode but the hydraulic powered actuator  400  is in bypass mode. In such an example, the electric motor  524  rotates the shaft  510  to rotate the crank arm  306 . Because the pinion gear  432  is engaged with the rack  430  ( FIG. 4A ), the pinion gear  432  back-drives the rack  430  and the pistons. As disclosed above, the hydraulic powered actuator  400  can be switched to the bypass mode (shown in  FIG. 4C ). Assuming the flap actuator  202  is operated in the hybrid mode, both the hydraulic powered actuator  400  and the electric powered actuator  500  are in active mode simultaneously. In such an example, the outpower of crank arm  306  is a summation of both the hydraulic powered actuator  400  and the electric powered actuator  500 . 
     As disclosed above, the first or second REUs  232 ,  234  ( FIG. 4A ) controls the position of the outboard left flap  112  ( FIG. 1 ) using the position sensor  482  as a feedback. In some examples, the position sensor  482  is operatively coupled to the carrier  536 . For example, as shown in  FIG. 5 , the position sensor  482  is coupled to a gear  540  that is engaged with a gear  542  on the carrier  536 . The gear  540  rotates as the carrier  536  is rotated. The position sensor  482  measures the position (e.g., angular position) of the gear  540 , which corresponds to the position of the crank arm  306  and, thus, the position of the outboard left flap  112 . Therefore, the position sensor is operatively coupled to the shaft  510 . The position sensor  482  can be implemented as any type of sensor, and for positioning accuracy a resolver is often used. 
     In the illustrated example, the first flap actuator  202  includes a no-back  544  (e.g., a directional movement restrictor). The no-back  544  allows the crank arm  306  be actuated by the motion of shaft  510  and restricts movement of the shaft  510  due to the crank arm  306 . In the illustrated example, the no-back  544  is coupled to the shaft  510  and the support bracket  504 . 
     To operate the electric powered actuator  500  in the electric powered mode or the hybrid mode, the first ACE  222  activates the first switch  258 , which electrically connects the aircraft electrical system  248  to the first EMCU  250 . The first EMCU  250  controls the supply of electric power for activating the electric motor  524  and the electric brake  538 . The first EMCU  250  controls the electric motor  524  and the electric brake  538  based on commands from the first ACE  222 . In particular, the first EMCU  250  receives a commanded position from the first ACE  222 , and generates control signals for the electric motor  524  and the electric brake  538 . The first EMCU  250  can activate the electric motor  524  to move the outboard left flap  112  to any position between the stowed position (shown in  FIG. 3A ) and the deployed position (shown in  FIG. 3B ). Once in the desired position, the first EMCU  250  can deactivate the electric motor  524  and deactivate the electric brake  538 . The no-back  544  holds the outboard left flap  112  in position. The first EMCU  250  controls the position of the crank arm  306  (and, thus, the outboard left flap  112 ) via the position sensor  482  from the first REU  232  or the second REU  234 . In this manner, the first ACE  222  controls the electric powered actuator  500  of the first flap actuator  202 . 
     In this example, the first ACE  222  is also one of the ACEs that controls the hydraulic powered actuator  400  (as shown in  FIGS. 4A-4C ). In other ones of the flap actuators  202 - 216 , a different ACE controls the electric powered actuator than the hydraulic powered actuator. For example, referring back to  FIGS. 2A and 2B , the first and second ACEs  222 ,  224  control the hydraulic powered actuator of the second flap actuator  204  in the hydraulic powered mode and the hybrid mode, but the third ACE  226  controls the electric powered actuator of the second flap actuator  204  in the electric powered mode and the hybrid mode. 
     Referring back to  FIGS. 2A and 2B , the system  200  includes a redundant architecture that enables control of the flaps  112 - 118  during various failures situations. As shown in  FIG. 2A , each of the hydraulic powered actuators of the flap actuators  202 - 216  is controllable by two of the ACEs  222 - 228 . This results in a redundant system that enables the DTE control system  218  to continue to operate in the hydraulic powered mode even if one or more of the ACEs  222 - 218  and/or the REUs  232 - 246  fail and/or otherwise become inoperable. For example, as shown in  FIG. 2A , the first flap actuator  202  is electrically coupled to and controllable by the first ACE  222  (via the first REU  232 ) and the second ACE  224  (via the second REU  234 ). During normal operation, the first ACE  222  and the second ACE  224  provide the same command signals for control of the first flap actuator  202 . However, if the first ACE  222  and/or otherwise becomes inoperable, the second ACE  224  can still control the hydraulic powered actuator of the first flap actuator  202 . Thus, no interruption of the system  200  occurs. Each of the other flap actuators  114 - 118  is similarly electrically coupled to and controllable by two of the ACEs  222 - 228 . 
     The example system  200  can also continue to operate even if a second ACE fails. For example, if the first ACE  222  and the third ACE  226  fail and/or otherwise become inoperable, the DTE control system  218  can continue to control the flap actuators  202 - 216  in the hydraulic powered mode using the second ACE  224  and the fourth ACE  228 . In particular, the second ACE  224  can continue to control the first, second, seventh, and eighth flap actuators  202 ,  204 ,  214 ,  216  for moving the outboard left and right flaps  112 ,  118 . Similarly, the fourth ACE  228  can continue to control the third, fourth, fifth, and sixth flap actuators  206 - 212  for moving the inboard left and right flaps  114 ,  116 . 
     In some examples, if two of the ACEs  222 - 228  fail that are associated with the same flap, the hydraulic powered actuators of those flaps are switched to the bypass mode and are held in position via the no-backs. As such, the flap is not movable. For example, if the first and second ACEs  222 ,  224  fail and/or otherwise become inoperable, the first, second, seventh, and eighth flap actuators  202 ,  204 ,  214 ,  216  are switched to their bypass mode and the outboard left and right flaps  112 ,  118  are held in their current positions via their no-backs. In such an instance, the inboard left and right flaps  114 ,  116  may be still be operable. The alert generator  270  may generate an alert at the flight deck  272  to indicate that certain ones of the flaps are inoperable. A trained pilot can account for this situation and compensate for the loss of one the pair of flaps. 
     If there is a mechanical failure of one of the flap actuators  202 - 216 , all of the flap actuators associated with the ACE connected to the failed flap actuator can be commanded to the bypass position and the flaps can be held in place, such that a symmetrical pair of the flaps is inoperable. For example, assume there is a mechanical failure of the first flap actuator  202 . In such an instance, the first and second ACEs  222 ,  224  command the hydraulic powered actuators associated with the first, second, seventh, and eighth flap actuators  202 ,  204 ,  214 ,  216  to switch to their bypass mode and the outboard left and right flaps  112 ,  118  are held in their current positions via the no-backs of the first, second, seventh, and eighth flap actuators  202 ,  204 ,  214 ,  216 . In such an instance, the alert generator  270  may generate an alert at the flight deck  272  to indicate that certain ones of the flaps are inoperable. A trained pilot can account for this situation and compensate for the loss of one the pair of flaps. 
     Another failure situation may occur is if the aircraft hydraulic systems  230  ( FIG. 4A ) fails. In such an instance, the ACEs  222 - 228  switch each of the flap actuators  202 - 216  from their hydraulic powered mode to their electric powered mode, so that the electric powered actuators can be used to control the flaps  112 - 118 . For example, the ACEs  222 - 228  switch the mode selector valves (e.g., the MSV  448  ( FIG. 4A )) to their bypass states, and activate the switches  258 - 264  to provide electrical power to the EMCUs  250 - 256 . Then, the EMCUs  250 - 256  can control the electric powered actuators to move the respective flaps  112 - 118 . 
     In another failure instance, the aircraft hydraulic system  230  can lose some but not all of its hydraulic power. For example, the aircraft hydraulic system  230  may be pressurized using pumps driven by the engines  108 ,  110  ( FIG. 1 ). If one of the engines  108 ,  110  fails and/or otherwise becomes inoperable, the pressure in the aircraft hydraulic system  230  is reduced. In such an instance, the ACEs  222 - 228  can operate the flaps actuators  202 - 216  in their hybrid mode. In the hybrid mode, the hydraulic powered actuator and the electric powered actuator of each of the flap actuators  202 - 216  operate together to control the movement of the corresponding flaps  112 - 118 . 
     While an example manner of implementing the DTE control system  218  is illustrated in  FIGS. 2A and 2B , one or more of the elements, processes and/or devices illustrated in  FIGS. 2A and 2B  may be combined, divided, re-arranged, omitted, eliminated and/or implemented in any other way. Further, the example ACEs  222 - 228 , the example REUs  232 - 246 , the example EMCUs  250 - 256 , the example switches  258 - 264 , the example failure detector  266 , the example alert generator  270 , and/or, more generally, the example DTE control system  218  of  FIGS. 2A and 2B  may be implemented by hardware, software, firmware and/or any combination of hardware, software and/or firmware. Thus, for example, any of the example ACEs  222 - 228 , the example REUs  232 - 246 , the example EMCUs  250 - 256 , the example switches  258 - 264 , the example failure detector  266 , the example alert generator  270 , and/or, more generally, the example DTE control system  218  could be implemented by one or more analog or digital circuit(s), logic circuits, programmable processor(s), programmable controller(s), graphics processing unit(s) (GPU(s)), digital signal processor(s) (DSP(s)), application specific integrated circuit(s) (ASIC(s)), programmable logic device(s) (PLD(s)) and/or field programmable logic device(s) (FPLD(s)). When reading any of the apparatus or system claims of this patent to cover a purely software and/or firmware implementation, at least one of the example ACEs  222 - 228 , the example REUs  232 - 246 , the example EMCUs  250 - 256 , the example switches  258 - 264 , the example failure detector  266 , and/or the example alert generator  270  is/are hereby expressly defined to include a non-transitory computer readable storage device or storage disk such as a memory, a digital versatile disk (DVD), a compact disk (CD), a Blu-ray disk, etc. including the software and/or firmware. Further still, the example DTE control system  218  of  FIGS. 2A and 2B  may include one or more elements, processes and/or devices in addition to, or instead of, those illustrated in  FIGS. 2A and 2B , and/or may include more than one of any or all of the illustrated elements, processes and devices. As used herein, the phrase “in communication,” including variations thereof, encompasses direct communication and/or indirect communication through one or more intermediary components, and does not require direct physical (e.g., wired) communication and/or constant communication, but rather additionally includes selective communication at periodic intervals, scheduled intervals, aperiodic intervals, and/or one-time events. 
     Flowchart representative of example hardware logic, machine readable instructions, hardware implemented state machines, and/or any combination thereof for implementing the DTE control system  218  of  FIGS. 2A and 2B  are shown in  FIGS. 6-11 . The machine readable instructions may be one or more executable programs or portion(s) of an executable program for execution by a computer processor and/or processor circuitry, such as the processor  1412  shown in the example processor platform  1400  discussed below in connection with  FIG. 14 . The program may be embodied in software stored on a non-transitory computer readable storage medium such as a CD-ROM, a floppy disk, a hard drive, a DVD, a Blu-ray disk, or a memory associated with the processor  1412 , but the entire program and/or parts thereof could alternatively be executed by a device other than the processor  1412  and/or embodied in firmware or dedicated hardware. Further, although the example program is described with reference to the flowcharts illustrated in  FIGS. 6-14 , many other methods of implementing the example DTE control system  218  may alternatively be used. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, or combined. Additionally or alternatively, any or all of the blocks may be implemented by one or more hardware circuits (e.g., discrete and/or integrated analog and/or digital circuitry, an FPGA, an ASIC, a comparator, an operational-amplifier (op-amp), a logic circuit, etc.) structured to perform the corresponding operation without executing software or firmware. The processor circuitry may be distributed in different network locations and/or local to one or more devices (e.g., a multi-core processor in a single machine, multiple processors distributed across a server rack, etc). 
     The machine readable instructions described herein may be stored in one or more of a compressed format, an encrypted format, a fragmented format, a compiled format, an executable format, a packaged format, etc. Machine readable instructions as described herein may be stored as data or a data structure (e.g., portions of instructions, code, representations of code, etc.) that may be utilized to create, manufacture, and/or produce machine executable instructions. For example, the machine readable instructions may be fragmented and stored on one or more storage devices and/or computing devices (e.g., servers) located at the same or different locations of a network or collection of networks (e.g., in the cloud, in edge devices, etc.). The machine readable instructions may require one or more of installation, modification, adaptation, updating, combining, supplementing, configuring, decryption, decompression, unpacking, distribution, reassignment, compilation, etc. in order to make them directly readable, interpretable, and/or executable by a computing device and/or other machine. For example, the machine readable instructions may be stored in multiple parts, which are individually compressed, encrypted, and stored on separate computing devices, wherein the parts when decrypted, decompressed, and combined form a set of executable instructions that implement one or more functions that may together form a program such as that described herein. 
     In another example, the machine readable instructions may be stored in a state in which they may be read by processor circuitry, but require addition of a library (e.g., a dynamic link library (DLL)), a software development kit (SDK), an application programming interface (API), etc. in order to execute the instructions on a particular computing device or other device. In another example, the machine readable instructions may need to be configured (e.g., settings stored, data input, network addresses recorded, etc.) before the machine readable instructions and/or the corresponding program(s) can be executed in whole or in part. Thus, machine readable media, as used herein, may include machine readable instructions and/or program(s) regardless of the particular format or state of the machine readable instructions and/or program(s) when stored or otherwise at rest or in transit. 
     The machine readable instructions described herein can be represented by any past, present, or future instruction language, scripting language, programming language, etc. For example, the machine readable instructions may be represented using any of the following languages: C, C++, Java, C#, Perl, Python, JavaScript, HyperText Markup Language (HTML), Structured Query Language (SQL), Swift, etc. 
     As mentioned above, the example processes of  FIGS. 6-11  may be implemented using executable instructions (e.g., computer and/or machine readable instructions) stored on a non-transitory computer and/or machine readable medium such as a hard disk drive, a flash memory, a read-only memory, a compact disk, a digital versatile disk, a cache, a random-access memory and/or any other storage device or storage disk in which information is stored for any duration (e.g., for extended time periods, permanently, for brief instances, for temporarily buffering, and/or for caching of the information). As used herein, the term non-transitory computer readable medium is expressly defined to include any type of computer readable storage device and/or storage disk and to exclude propagating signals and to exclude transmission media. 
     “Including” and “comprising” (and all forms and tenses thereof) are used herein to be open ended terms. Thus, whenever a claim employs any form of “include” or “comprise” (e.g., comprises, includes, comprising, including, having, etc.) as a preamble or within a claim recitation of any kind, it is to be understood that additional elements, terms, etc. may be present without falling outside the scope of the corresponding claim or recitation. As used herein, when the phrase “at least” is used as the transition term in, for example, a preamble of a claim, it is open-ended in the same manner as the term “comprising” and “including” are open ended. The term “and/or” when used, for example, in a form such as A, B, and/or C refers to any combination or subset of A, B, C such as (1) A alone, (2) B alone, (3) C alone, (4) A with B, (5) A with C, (6) B with C, and (7) A with B and with C. As used herein in the context of describing structures, components, items, objects and/or things, the phrase “at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. Similarly, as used herein in the context of describing structures, components, items, objects and/or things, the phrase “at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. As used herein in the context of describing the performance or execution of processes, instructions, actions, activities and/or steps, the phrase “at least one of A and B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. Similarly, as used herein in the context of describing the performance or execution of processes, instructions, actions, activities and/or steps, the phrase “at least one of A or B” is intended to refer to implementations including any of (1) at least one A, (2) at least one B, and (3) at least one A and at least one B. 
     As used herein, singular references (e.g., “a”, “an”, “first”, “second”, etc.) do not exclude a plurality. The term “a” or “an” entity, as used herein, refers to one or more of that entity. The terms “a” (or “an”), “one or more”, and “at least one” can be used interchangeably herein. Furthermore, although individually listed, a plurality of means, elements or method actions may be implemented by, e.g., a single unit or processor. Additionally, although individual features may be included in different examples or claims, these may possibly be combined, and the inclusion in different examples or claims does not imply that a combination of features is not feasible and/or advantageous. 
       FIG. 6  is a flowchart of an example process  600  that can be implemented by the DTE control system  218  of the system  200  of  FIGS. 2A and 2B . The example process  600  can be used to determine if a failure has occurred and disable certain one of the flap actuators  202 - 216  or switch certain ones of the flap actuators  202 - 216  between the different modes. The example process  600  may begin when the aircraft  100  is first dispatched. At block  602 , the failure detector  266  determines if one of the ACEs  222 - 228  is inoperable. In some examples, the failure detector  266  can determine if one of the ACEs  222 - 228  is inoperable based on feedback from the one or more sensor(s)  268 . 
     If the failure detector  266  determines that one of the ACEs  222 - 228  is inoperable (determined at block  602 ), control proceeds to block  604 . At block  604 , the failure detector  266  determines if a second ACE is inoperable. If two of the ACEs  222 - 228  are inoperable, control proceeds to the example process disclosed in connection with  FIG. 7 . Otherwise, if a second ACE is not inoperable (i.e., only one ACE is inoperable), control proceeds to block  606 . 
     If none of the ACEs  222 - 228  are inoperable, or if only one of the ACEs  222 - 228  is inoperable, control proceeds to block  606 . At block  606 , the DTE control system  218  operates the flap actuators  202 - 216  in the hydraulic (normal) powered mode. In the hydraulic powered mode, the ACEs  222 - 228  control the flap actuators  202 - 216  using their hydraulic powered actuators. As disclosed above, the DTE control system  218  includes an architecture using redundant ACEs. Therefore, if one of the ACEs  222 - 228  is inoperable, another ACE can continue to operate the associated flap actuators. For example, if the first ACE  222  fails, the second ACE  224  can continue to operate the first, second, seventh, and eighth flap actuators  202 ,  204 ,  214 ,  216  using their hydraulic powered actuators. 
     During flight, the DTE control system  218  continues to monitor to determine if another failure occurs. Depending on the type of failure and/or whether other failures are present, the DTE control system  218  may continue to operate in the hydraulic (normal) powered mode or switch to the electric powered mode or the hybrid mode. 
     At block  608 , the failure detector  266  determines if there is a mechanical failure of one of the flap actuators  202 - 216 . In some examples, the failure detector  266  can determine if there a mechanical failure of one of the flap actuators  202 - 216  based on feedback from the one or more sensor(s)  268 . If there is a mechanical failure of one of the flap actuators  202 - 216 , control proceeds to the example process disclosed in connection with  FIG. 8 . If there is not a mechanical failure of one of the flap actuators  202 - 216 , control proceeds to block  610 . 
     At block  610 , the failure detector  266  determines if there has been a loss of the aircraft hydraulic system  230 . In some examples, the failure detector  266  can determine if there has been a loss of the aircraft hydraulic system  230  based on feedback from the one or more sensor(s)  268 . For example, one of the sensor(s)  268  may be a pressure sensor that monitors the pressure of the aircraft hydraulic system  230 . If the pressure drops below a threshold, the failure detector  266  determines there has been a loss of the aircraft hydraulic system  230 . If there has been a loss of the aircraft hydraulic system  230 , control proceeds to the example process disclosed in connection with  FIG. 9 . If there has not been a loss of the aircraft hydraulic system  230 , control proceeds to block  612 . 
     At block  612 , the failure detector  266  determines if there is a malfunction of one of the hydraulic control modules (e.g., the HCM  404 ). A malfunction may occur if one of the electrical components (e.g., a solenoid of a solenoid valve) has failed. If there is a malfunction of one of the hydraulic control modules, control proceeds to the example process disclosed in connection with  FIG. 10 . If there has not been a malfunction of one of the hydraulic control modules, control proceeds to block  614 . 
     At block  614 , the failure detector  266  determines if one of the engines  108 ,  110  of the aircraft  100  has failed. The failure of one of the engines  108 ,  110  causes a reduction in hydraulic power (e.g., a reduction in pressure) in the aircraft hydraulic system  230 . If one of the engines  108 ,  110  has failed, control proceeds to the example process disclosed in connection with  FIG. 11 . If one of the engines has not failed (i.e., both of the engines  108 ,  110  are operable), control proceeds back to block  602 . In such an instance, the DTE control system  218  continues to operate the flap actuators  202 - 216  in their hydraulic powered modes. The example process  600  can be repeated at a certain frequency (e.g., every second, every minute, etc.) to continuously check for failure(s) and dynamically switch between the different modes based on the failure(s). 
       FIG. 7  is a flowchart of an example process  700  implemented by the DTE control system  218  of the system  200  when two of the ACEs  222 - 228  are inoperable. In some examples, the failure detector  266  determines two of the ACEs  222 - 228  have failed at block  604  of  FIG. 6 . At block  702 , the failure detector  266  determines whether the two ACEs that failed control the same flap. In some examples, the failure detector  266  utilizes the case tables  1 - 16  shown in  FIGS. 12A-12D . The case tables are labeled Case  1 -Case  16 . These case tables may be stored in a memory, such as a mass storage device  1428  in  FIG. 14 . In the case tables, a number “1” means a failure of an ACE to control its associated flap actuators, and a number “0” means the ACE operation is normal. The first column of case tables (Cases  1 ,  5 ,  9 ,  13 ) show instances when only one ACE has failed. The second, third, and fourth columns of the case tables (Cases  2 - 4 ,  6 - 8 ,  10 - 12 ,  14 - 16 ) show instances where a second ACE has failed during flight. The failure detector  266  consults these case tables to determine if the two ACEs that failed control the same flap. In particular, Cases  2 ,  6 ,  12 , and  16  represent instances where the two failed ACEs control the same flap, whereas Cases  3 ,  4 ,  7 ,  8 ,  10 ,  11 ,  14 , and  15  represent instances where the two failed ACEs do not control the same flap. 
     If the two failed ACEs do not control the same flap, such as in Cases  3 ,  4 ,  7 ,  8 ,  10 ,  11 ,  14 , and  15 , control proceeds to block  704 . At block  704 , the DTE control system  218  operates the flap actuators  202 - 216  in the hydraulic (normal) mode. For example, in Case  3 , the first ACE  222  and the third ACE  226  have failed. However, the first ACE  222  and the third ACE  226  do not control the same flaps. Therefore, the second ACE  224  can still control the flap actuators  202 ,  204 ,  214 ,  216  associated with the outboard left and right flaps  112 ,  118 , and the fourth ACE  228  can still control the flap actuators  216 - 212  associated with the inboard left and right flaps  114 ,  116 . As such, the DTE control system  218  can continue to operate the system  200  using hydraulic power as normal. Further, as shown in  FIGS. 12A-12D , a flight message is not displayed. In some examples, control proceeds back to block  602  of  FIG. 6  and the example process  600  repeats. 
     If the two failed ACEs control the same flap, such as in Cases  2 ,  6 ,  12 , and  16 , control proceeds to block  706 . For example, in Cases  2  and  6 , the first ACE  222  and the second ACE  224  have failed. The first and second ACEs  222 ,  224  control the first and second flap actuators  202 ,  204  associated with the outboard left flap  112  and the seventh and eighth flap actuators  214 ,  216  associated with the outboard right flap  118 . Similarly, in Cases  12  and  16 , the third ACE  226  and the fourth ACE  228  have failed. The third and fourth ACEs  226 ,  228  control the flap actuators associated with the inboard left and right flaps  114 ,  116 . 
     At block  706 , the flap actuators associated with the two failed ACEs are controlled or switched to their bypass modes, and the associated flaps are held in place via their no-backs. In some example, controlling the flap actuators to their bypass mode occurs automatically when the two ACEs fail. For example, as explained in connection with  FIG. 4C , if the first and second ACEs  222 ,  224  fail, the first and second REUs  232 ,  234  cease power to the solenoid of the SOV  446 , which controls the SOV  446  to its OFF  452 , which controls the MSV  448  to its bypass state  464 . In other examples, the first and/or second ACEs  222 ,  224  may command the first and/or second REUs  232 ,  234  to control the SOV  446  to its OFF  452 . The no-backs (e.g., the no-back  544 ) associated with the flap actuators hold the flap actuators in their current positions and, thus, the associated flaps are locked in place. For example, in Case  2 , the first and second ACEs  222 ,  224  have failed. In such an instance, the hydraulic powered actuators associated with the first, second, seventh, and eighth flap actuators  202 ,  204 ,  214 ,  216  are controlled or switched to their bypass modes. The no-backs associated with the first, second, seventh, and eighth actuators  202 ,  204 ,  214 ,  216  hold the actuators in place and, thus, lock the outboard left and right flaps  112 ,  118  in place. As a result, the outboard left and right flaps  112 ,  118  are inoperable. Even though the outboard left and right flaps  112 ,  118  are inoperable, the inboard left and right flaps  114 ,  116  can still be controlled as normal and used to control the aircraft  100 . 
     At block  708 , the alert generator  270  generates an alert at the flight deck  272 . The alert may be an activation of a light, display of a message, activation of audible alert, and/or any other type of alert. The alert signals to the pilot that the pilot is to follow a non-normal procedure for operating the aircraft  100  (e.g., landing the aircraft), because one symmetrical pair of the flaps is inoperable. This type of malfunction is considered minor, because a trained pilot can account for this failure and still safely land the aircraft  100 . Thus, the system  200  can continue to operate with only a minor change in function. 
       FIG. 8  is a flowchart of an example process  800  implemented by the DTE control system  218  of the system  200  when there is a mechanical failure of one of the flap actuators  202 - 216 . In some examples, the failure detector  266  determines there is a mechanical failure of one of the flap actuators  202 - 216  at block  608  of  FIG. 6 . At block  802 , all of the flap actuators associated with an ACE of the failed flap actuator are controlled or switched to their bypass mode, and the associated flaps are held in place via their no-backs. In some examples, the failure detector  266  utilizes the case tables  1 - 8  shown in  FIG. 13  to determine which flap actuators to control to their bypass modes. The case tables are labeled Case  1 -Case  8 . These case tables may be stored in a memory, such as the mass storage device  1428  in  FIG. 14 . In the case tables of  FIG. 13 , a number “1” means a failure of the flap actuator, and a number “0” means the flap actuator is operating normally. In these case tables, a white block indicates the flap actuator is to be controlled or switched to its bypass mode, and a shaded block indicates the flap actuator can be operated in the normal mode via hydraulic actuation. For example, assume the first flap actuator  202  (the outboard actuator of the outboard left flap  112 ) has failed. This event corresponds to Case  1 . In Case  1 , the blocks for the outboard (OB) and inboard (IB) actuators for the outboard (OB) left flap  112  and the outboard right flap  118  are white. These correspond to the first, second, seventh, and eighth flap actuators  202 ,  204 ,  214 ,  216 . These flap actuators are all controlled by the same ACEs. In such an instance, the hydraulic powered actuators associated with the first, second, seventh, and eighth flap actuators  202 ,  204 ,  214 ,  216  are controlled to their bypass modes (e.g., via a command from the first and second ACEs  222 ,  224  and/or deactivation of the first and second ACEs  222 ,  224 ). The no-back devices associated with the first, second, seventh, and eighth actuators  202 ,  204 ,  214 ,  216  hold the actuators in place and, thus, lock the outboard left and right flaps  112 ,  118  in place. As a result, the outboard left and right flaps  112 ,  118  (which are a symmetrical pair of flaps) are inoperable. Even though the outboard left and right flaps  112 ,  118  are inoperable, the inboard left and right flaps  114 ,  116  can still be controlled as normal and used to control the aircraft  100 . 
     At block  804 , the alert generator  270  generates an alert at the flight deck  272 , similar to the alert generated at block  708  in  FIG. 7 . The alert signals to the pilot that the pilot is to follow a non-normal procedure for operating the aircraft (e.g., landing the aircraft), because one symmetrical pair of the flaps is inoperable. This type of malfunction is considered minor, because a trained pilot can account for this failure and still safely land the aircraft  100 . Thus, the system  200  can continue to operate with only a minor change in function. 
       FIG. 9  is a flowchart of an example process  900  implemented by the DTE control system  218  of the system  200  when there is a loss of the aircraft hydraulic system  230 . In some examples, the failure detector  266  determines when there is a loss of the aircraft hydraulic system  230  at block  610  of  FIG. 6 . Without hydraulic power, the hydraulic powered actuators of the flap actuators  202 - 216  cannot be controlled. At block  902 , the DTE control system  218  operates the flap actuators  202 - 216  in their electric (alternate) powered mode. In some examples, the ACEs  222 - 228  control or switch the flap actuators  202 - 216  to their electric powered modes by activating the switches  252 - 258 , which enables the EMCUs  250 - 256  to control the electric powered actuators of the flap actuators  202 - 216 . Further, the ACEs  222 - 228  switch the hydraulic powered actuators into their bypass modes (e.g., by switching the SOV  446  to the OFF  452 ). Once in the electric powered mode, the ACEs  222 - 228  and EMCUs  250 - 256  can control the flap actuators  202 - 216  by operating the electric powered actuators of the flap actuators  202 - 216 . Therefore, the DTE control system  218  is switched or controlled from the hydraulic (normal) powered mode to the electric (alternate) powered mode. In this example, all of the flaps  112 - 118  are still operable. 
       FIG. 10  is a flowchart of an example process  1000  implemented by the DTE control system  218  of the system  200  when there is a malfunction in one of the hydraulic control modules. This may be determined by the failure detector  266  at block  612  of  FIG. 6 . If there is a malfunction in one of the hydraulic control modules, at block  1002 , the DTE control system  218  can continue to operate the flap actuators  202 - 218  in the hydraulic (normal) powered mode. As disclosed above, the hydraulic control modules (e.g., the HCM  404  of  FIGS. 4A-4C ) include redundant architecture, such that if one electrical components and/or one REUs fails, another electrical component and/or another REU can continue to operate the hydraulic control module. For example, a disclosed in connection with the HCM  404  of  FIGS. 4A-4C , the SOV  446  and the EHSV  450  both include dual coils (e.g., channels). As a result if one of the coils fails and/or one of the REUs  232 ,  234  fails, the other coil and/or other REU can continue to operate the SOV  446  and the EHSV  450 . Therefore, the DTE control system  218  can continue to operate the flap actuators  202 - 216  in the hydraulic (normal) powered mode. 
       FIG. 11  is a flowchart of an example process  1100  implemented by the DTE control system  218  of the system  200  when one of the engines  108 ,  110  has failed. This may be determined by the failure detector  266  at block  614  of  FIG. 6 . When one of the engines  108 ,  110  fails, the pressure of the hydraulic fluid of the aircraft hydraulic system  230  is reduced (e.g., halved or cut by 50%). Thus, less pressure is provided for actuating the hydraulic powered actuators of the flap actuators  202 - 216 . At block  1102 , the DTE control system  218  operates the flap actuators  202 - 216  in their hybrid mode. In particular, the DTE control system  218  operates the flap actuators  202 - 216  by activating/actuating both the hydraulic powered actuators and the electric powered actuators simultaneously. The electric powered actuators help compensate for the reduction in power from the hydraulic powered actuators. For example, referring back to  FIGS. 4A-4D , the hydraulic powered actuator  400  and the electric powered actuator  500  can be activated/actuated simultaneously to move the crank arm  306  and, thus, move the outboard left flap  112 . The hydraulic powered actuator  400  is controlled by the first and/or second ACEs  222 ,  224 , and the electric powered actuator  500  is controlled by the first ACE  222 . Therefore, operating the flap actuator  202  in the hybrid mode can include controlling the hydraulic powered actuator  400  via the first ACE  222  and/or the second ACE  224 , and controlling the electric powered actuator  500  via the first ACE  222 . As such, the DTE control system  218  uses a combination of both hydraulic and electric power to operate the flap actuators  202 - 216 . 
     Some aircraft regulations govern the retraction maneuver requirements from the deployed position (full maximum flap) to the stowed position. The hydraulic system and the flap actuators of the aircraft are sized according to these requirements. Because the flap actuators  202 - 216  disclosed herein can be operated using a combination of hydraulic power and electrical power, the demand of the aircraft hydraulic system  230  is reduced. Thus, the hydraulic pump(s) in the aircraft  100  can be reduced in size and power. This reduces the overall load on the engines  108 ,  110 . Further, this reduces the physical size of the flap actuators  202 - 216 , which reduces the spacing requirements in the wings  104 ,  106  of the aircraft  100   t . This enables thinner, lighter wings to be constructed, which are more efficient. 
       FIG. 14  is a block diagram of an example processor platform  1400  structured to execute the instructions of  FIGS. 6-11  to implement the DTE control system  218  of  FIGS. 2A and 2B . The processor platform  1400  can be, for example, a server, a personal computer, a workstation, a self-learning machine (e.g., a neural network), a mobile device (e.g., a cell phone, a smart phone, a tablet such as an iPad′), a DVD player, a CD player, a digital video recorder, a Blu-ray player, a gaming console, or any other type of computing device. 
     The processor platform  1400  of the illustrated example includes a processor  1412 . The processor  1412  of the illustrated example is hardware. For example, the processor  1412  can be implemented by one or more integrated circuits, logic circuits, microprocessors, GPUs, DSPs, or controllers from any desired family or manufacturer. The hardware processor may be a semiconductor based (e.g., silicon based) device. In this example, the processor  1412  implements the example ACEs  222 - 228 , the example REUs  232 - 246 , the example EMCUs  250 - 256 , the example switches  258 - 264 , the example failure detector  266 , and the example alert generator  270 . 
     The processor  1412  of the illustrated example includes a local memory  1413  (e.g., a cache). The processor  1412  of the illustrated example is in communication with a main memory including a volatile memory  1414  and a non-volatile memory  1416  via a bus  1418 . The volatile memory  1414  may be implemented by Synchronous Dynamic Random Access Memory (SDRAM), Dynamic Random Access Memory (DRAM), RAMBUS® Dynamic Random Access Memory (RDRAM®) and/or any other type of random access memory device. The non-volatile memory  1416  may be implemented by flash memory and/or any other desired type of memory device. Access to the main memory  1414 ,  1416  is controlled by a memory controller. 
     The processor platform  1400  of the illustrated example also includes an interface circuit  1420 . The interface circuit  1420  may be implemented by any type of interface standard, such as an Ethernet interface, a universal serial bus (USB), a Bluetooth® interface, a near field communication (NFC) interface, and/or a PCI express interface. 
     In the illustrated example, one or more input devices  1422  are connected to the interface circuit  1420 . The input device(s)  1022  permit(s) a device and/or a user to enter data and/or commands into the processor  1412 . In this example, the input device(s)  1422  include the sensor(s)  268  and the position sensors (e.g., the position sensor  482 ). Additionally or alternatively, the input device(s) can be implemented by, for example, an audio sensor, a microphone, a camera (still or video), a keyboard, a button, a mouse, a touchscreen, a track-pad, a trackball, isopoint and/or a voice recognition system. 
     One or more output devices  1424  are also connected to the interface circuit  1420  of the illustrated example. In this example, the output device(s)  1424  include the flap actuators  202 - 216  (e.g., the HCMs of the hydraulic powered actuators, and the electric motors of the electric powered actuators) and the flight deck  272 . Additionally or alternatively, the output device(s)  1024  can be implemented, for example, by display devices (e.g., a light emitting diode (LED), an organic light emitting diode (OLED), a liquid crystal display (LCD), a cathode ray tube display (CRT), an in-place switching (IPS) display, a touchscreen, etc.), a tactile output device, a printer and/or speaker. The interface circuit  1420  of the illustrated example, thus, typically includes a graphics driver card, a graphics driver chip and/or a graphics driver processor. 
     The interface circuit  1420  of the illustrated example also includes a communication device such as a transmitter, a receiver, a transceiver, a modem, a residential gateway, a wireless access point, and/or a network interface to facilitate exchange of data with external machines (e.g., computing devices of any kind) via a network  1426 . The communication can be via, for example, an Ethernet connection, a digital subscriber line (DSL) connection, a telephone line connection, a coaxial cable system, a satellite system, a line-of-site wireless system, a cellular telephone system, etc. 
     The processor platform  1400  of the illustrated example also includes one or more mass storage devices  1428  for storing software and/or data. Examples of such mass storage devices  1428  include floppy disk drives, hard drive disks, compact disk drives, Blu-ray disk drives, redundant array of independent disks (RAID) systems, and digital versatile disk (DVD) drives. 
     The machine executable instructions  1432  of  FIGS. 6-11  may be stored in the mass storage device  1428 , in the volatile memory  1414 , in the non-volatile memory  1416 , and/or on a removable non-transitory computer readable storage medium such as a CD or DVD. 
     From the foregoing, it will be appreciated that example methods, apparatus, systems, and articles of manufacture have been disclosed that provide redundant control of one or more flap actuators of an aircraft DTE actuation system. The examples disclosed herein enable the complete (or partial) control of the one or more flap actuators in the event of failure or loss of one or more components or systems of the aircraft. 
     Example linkage assemblies have also been disclosed that are more compact than known linkage systems. The example linkage systems enable the use of thinner wings, which produce more efficient flight. 
     Example hydraulic-electric flap actuators have also been disclosed that can advantageously operate in multiple modes to ensure continuous or near continuous operation of the flap actuator. The example hydraulic-electric flap actuators can operate in a hybrid mode in which both hydraulic power and electrical power is used to operate the flap actuator. This reduces the demand on the aircraft hydraulic systems, thereby enabling a reduction in the size and components of the aircraft hydraulic system. 
     Example methods, apparatus, systems, and articles of manufacture for redundant actuation of control surfaces are disclosed herein. Further examples and combinations thereof include the following: 
     Example 1 is an aircraft includes a wing and a flap coupled to the wing. The flap is movable between a stowed position and a deployed position. The aircraft also includes a distributed trailing edge (DTE) actuation system including a flap actuator coupled to the wing to move the flap. The flap actuator includes an integrated hydraulic powered actuator and electric powered actuator. The flap actuator is operable in a hydraulic powered mode in which the hydraulic powered actuator is activated to move the flap, an electric powered mode in which the electric powered actuator is activated to move the flap, and a hybrid mode in which the hydraulic powered actuator and the electric powered actuator are activated simultaneously to move the flap. 
     Example 2 includes the aircraft of Example 1, wherein the DTE actuation system includes a first actuator control electronics (ACE) and a second ACE. The flap actuator is controllable by the first ACE or the second ACE in the hydraulic powered mode, the electric powered mode, and the hybrid mode. 
     Example 3 includes the aircraft of Example 2, wherein the electric powered actuator is controllable by the first ACE in the electric powered mode and the hybrid mode. 
     Example 4 includes the aircraft of Example 3, wherein the DTE system includes an electric motor control unit (EMCU) to control the electric powered actuator based on commands from the first ACE. 
     Example 5 includes the aircraft of Example 4, wherein the DTE system includes a switch electrically coupled between an aircraft electrical system and the EMCU, the switch controllable by the first ACE. 
     Example 6 includes the aircraft of any of Examples 2-5, wherein the DTE actuation system includes a third ACE. The electric powered actuator of the flap actuator is controlled by the third ACE in the electric powered mode and the hybrid mode. 
     Example 7 includes the aircraft of any of Examples 1-6, wherein the flap actuator includes a hydraulic control module (HCM) to control the hydraulic powered actuator. The HCM includes a valve operable in a first state to move a crank arm of the flap actuator in a first direction and a second state to move the crank arm in a second direction. 
     Example 8 includes the aircraft of Example 7, wherein the DTE actuation system includes a first remote electronics unit (REU) and a second REU. The valve is controllable by the first REU or the second REU. 
     Example 9 includes the aircraft of Example 8, wherein the valve is a first valve. The HCM includes a second valve operable between a first state in which the second valve enables pressurized hydraulic fluid to be supplied to the first valve and a second state in which the second valve shuts off the supply of pressurized hydraulic fluid to the first valve. 
     Example 10 includes the aircraft of Example 9, wherein the second valve is controllable by the first REU or the second REU. 
     Example 11 includes the aircraft of Example 10, wherein, when the second valve is supplied with an electrical signal from at least one of the first REU or the second REU, the second valve is controlled to the first state, and when the second valve is not supplied with the electrical signal from at least one of the first REU or the second REU, the second valve is controlled to the second state. 
     Example 12 includes the aircraft of Example 11, wherein the first valve includes redundant electrically controlled coils interfaced with redundant control channels. 
     Example 13 includes the aircraft of Example 12, wherein the second valve includes redundant electrically controlled coils interfaced with redundant control channels. 
     Example 14 is an aircraft including a left wing, a right wing, flaps movable relative to trailing edges of the left and right wings, and a distributed trailing edge (DTE) actuation system. The DTE actuation system includes flap actuators coupled to the left and right wings to move the flaps. Each of the flap actuators is a rotary actuator including an integrated hydraulic powered actuator and electric powered actuator. The DTE actuation system also includes actuator control electronics (ACEs), wherein each of the hydraulic powered actuators of the flap actuators is controllable by at least two of the ACEs. 
     Example 15 includes the aircraft of Example 14, wherein: the flaps include an outboard left flap, an inboard left flap, an outboard right flap, and an inboard right flap; the ACEs include a first ACE, a second ACE, a third ACE, and a fourth ACE; the first and third ACEs control the hydraulic powered actuators of the flap actuators associated with the outboard left and right flaps; and the second and fourth ACEs control the hydraulic powered actuators of the flap actuators associated with the inboard left and right flaps. 
     Example 16 includes the aircraft of Example 15, wherein at least one of the electric powered actuators of the flap actuators associated with the outboard left and right flaps is controlled by the second ACE, and wherein at least one of the electric powered actuators of the flap actuators associated with the inboard left and right flaps is controlled by the third ACE. 
     Example 17 includes the aircraft of any of Examples 14-16, wherein the flap actuators include respective position sensors, and wherein data from the position sensors of two of the flap actuators associated with one of the flaps are processed by the ACEs to ensure position of the two of the flap actuators do not results in an unacceptable force fight threshold and to ensure the positions of the two of the flap actuators are synchronized. 
     Example 18 is method including determining an engine of an aircraft has failed, wherein failure of the engine causes a reduction in hydraulic power in an aircraft hydraulic system. The aircraft includes a flap actuator to move a flap relative to a trailing edge of a wing. The flap actuator includes an integrated hydraulic powered actuator and electric powered actuator. The method also includes, in response to determining the engine has failed, operating the flap actuator in a hybrid mode in which the hydraulic powered actuator and the electric powered actuator are activated simultaneously to move the flap. 
     Example 19 includes the method of Example 18, wherein the flap actuator is a rotary actuator. 
     Example 20 includes the method of Examples 18 or 18, wherein the operating of the flap actuator in the hybrid mode includes: controlling the hydraulic powered actuator via at least one of a first actuator control electronics (ACE) or a second ACE; and controlling the electric powered actuator via the first ACE. 
     Example 21 is a flap actuator for an aircraft. The flap actuator includes a crank arm rotatable about an axis. The crank arm is to be coupled to a flap of the aircraft via a linkage assembly. The flap actuator also includes a hydraulic powered actuator coupled to the crank arm. The hydraulic powered actuator is to rotate the crank arm when activated. The flap actuator further includes an electric powered actuator coupled to the crank arm. The electric powered actuator is to rotate the crank arm when activated. 
     Example 22 includes the flap actuator of Example 21, wherein the hydraulic powered actuator includes an integrated piston and rack assembly. The integrated piston and rack assembly includes a rack. The hydraulic powered actuator further includes a pinion gear engaged with the rack. The pinion gear is coupled to the crank arm such that linear movement of the rack rotates the crank arm. 
     Example 23 includes the flap actuator of Example 22, wherein the pinion gear is coupled to the crank arm via a shaft, and wherein the electric powered actuator is coupled to the shaft. 
     Example 24 includes the flap actuator of Example 23, wherein the hydraulic powered actuator includes a first housing, and wherein the integrated piston and rack assembly includes a first piston disposed in the first housing. The first piston includes a first sub-piston and a second sub-piston. The rack is coupled between the first sub-piston and the second sub-piston. 
     Example 25 includes the flap actuator of Example 24, wherein the integrated piston and rack assembly includes first and second tabs disposed on opposite sides of a ridge extending from an inner surface of the first housing. The ridge is engaged by the first and second tabs to prevent the integrated piston and rack assembly from rotating. 
     Example 26 includes the flap actuator of Examples 24 or 25, wherein the hydraulic powered actuator includes a second housing. The integrated piston and rack assembly includes a second piston disposed in the second housing and a piston rod coupling the first piston and the second piston such that the first and second pistons move together. 
     Example 27 includes the flap actuator of any of Examples 23-26, wherein the electric powered actuator includes an electric motor having a motor output shaft. 
     Example 28 includes the flap actuator of Example 27, wherein the motor output shaft is coupled to the shaft via a reduction gear system. 
     Example 29 includes the flap actuator of Example 28, wherein the reduction gear system includes a position sensor operatively coupled to the shaft. 
     Example 30 includes the flap actuator of any of Examples 22-29, wherein the electric powered actuator includes an electric brake that couples the motor output shaft and the pinion gear. 
     Example 31 includes the flap actuator of any of Examples 23-30, further including a no-back coupled to the shaft. 
     Example 32 is an aircraft including a wing, a flap, and a rotary flap actuator coupled to the wing. The rotary flap actuator is to move the flap between a stowed position and deployed positions. The rotary flap actuator includes an integrated hydraulic powered actuator and electric powered actuator. 
     Example 33 includes the aircraft of Example 32, wherein the wing includes a support bracket. The hydraulic powered actuator and the electric powered actuator are disposed on opposite sides of the support bracket. 
     Example 34 includes the aircraft of Examples 32 or 33, wherein the hydraulic powered actuator includes a first housing, a second housing, and an integrated piston and rack assembly. The integrated piston and rack assembly includes a first piston disposed in the first housing, a second piston disposed in the second housing, and a piston rod coupling the first and second pistons. 
     Example 35 includes the aircraft of Example 34, wherein the first piston includes a first sub-piston and a second sub-piston, and the integrated piston and rack assembly includes a rack coupled between the first and second sub-pistons. 
     Example 36 includes the aircraft of Example 35, wherein hydraulic powered actuator includes a pinion gear engaged with the rack. The pinion gear is coupled to a crank arm such that linear movement of the rack causes rotation of the crank arm. 
     Example 37 includes the aircraft of Examples 34 or 35, wherein the integrated piston and rack assembly includes first and second tabs disposed on opposite sides of a ridge extending from an inner surface of the first housing. The ridge is engaged by the first and second tabs to prevent the integrated piston and rack assembly from rotating. 
     Example 38 is a flap actuator for an aircraft. The flap actuator includes a crank arm, a hydraulic powered actuator coupled to the crank arm, and an electric powered actuator coupled to the crank arm. The hydraulic powered actuator and the electric powered actuator are simultaneously operable to rotate the crank arm. 
     Example 39 includes the flap actuator of Example 38, further including a shaft coupled to the crank arm. The hydraulic powered actuator is coupled to a first end of the shaft and the electric powered actuator is coupled to a second end of the shaft. 
     Example 40 includes the flap actuator of Example 39, wherein the hydraulic powered actuator includes a rack and a pinion gear engaged with the rack. The pinion gear is coupled to the shaft, such that linear movement of the rack causes rotation of the crank arm. 
     Although certain example methods, apparatus, systems, and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus, systems, and articles of manufacture fairly falling within the scope of the claims of this patent. 
     The following claims are hereby incorporated into this Detailed Description by this reference, with each claim standing on its own as a separate embodiment of the present disclosure.