Method and system for feathering a propeller

Abstract

Methods and systems for feathering a propeller are described herein. A solenoid is configured to feather the propeller when the solenoid is energized. An electronic controller is connected to the solenoid via a first electrical connection for energizing the solenoid to feather the propeller. An assist mechanism is connected to the solenoid via a second electrical connection for energizing the solenoid to feather the propeller. The second electrical connection is independent of the first electrical connection.

Description

Technical Field

[0001] The present disclosure relates generally to aircraft propeller control, and more particularly to feathering a propeller. Background Art

[0002] For a propeller driven aircraft, the control system can adjust the blade angle of the propeller blades to a feathered position to reduce the forward drag on the aircraft. For example, the propeller electronic controller can control a feathering solenoid and a protection solenoid, both of which have the ability to drive the propeller blades to a feathered position. Typically, an additional solenoid connected to a lever in the cockpit of the aircraft is provided for emergency purposes to feather the propeller. However, the additional solenoid adds weight and additional cost to the entire propeller system.

[0003] As such, a need exists for improvement. Summary of the invention

[0004] In one aspect, a system is provided that includes: a solenoid configured to feather a propeller when the solenoid is energized; an electronic controller connected to the solenoid via a first electrical connection for energizing the solenoid to feather the propeller; and a mechanism connected to the solenoid via a second electrical connection for energizing the solenoid to feather the propeller, the second electrical connection being independent of the first electrical connection.

[0005] In another aspect, a method for feathering a propeller is provided. The method includes: upon receiving a first request to energize the solenoid from an electronic controller via a first electrical connection to the solenoid, energizing the solenoid to feather the propeller; and upon receiving a second request to energize the solenoid from an auxiliary mechanism via a second electrical connection to the solenoid, energizing the solenoid to feather the propeller, the second electrical connection being independent of the first electrical connection.

[0006] In another aspect, a method is provided, the method comprising: connecting a solenoid to an electronic controller via a first electrical connection, the solenoid configured to feather a propeller when the solenoid is energized by the electronic controller via the first electrical connection; and connecting the solenoid to an auxiliary mechanism via a second electrical connection, the solenoid configured to feather the propeller when the solenoid is energized by the auxiliary mechanism via the second electrical connection, the second electrical connection being independent of the first electrical connection. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Reference is now made to the accompanying drawings, in which:

[0008] Figure 1 is a schematic diagram of an example gas turbine engine coupled to a propeller according to one or more embodiments;

[0009] Figure 2A is a schematic diagram illustrating a system for feathering a propeller according to one or more embodiments;

[0010] Figure 2B is a schematic diagram illustrating an example of a switch of a system for feathering a propeller according to one or more embodiments;

[0011] Figure 2C is a schematic diagram illustrating an example of a dual coil solenoid and a dual channel electronic controller according to one or more embodiments;

[0012] Figure 3A is a flow chart of a method for feathering a propeller according to one or more embodiments;

[0013] Figure 3B is a flowchart of another method according to one or more embodiments; and

[0014] Figure 4 is a block diagram of an example computing device in accordance with one or more embodiments.

[0015] It will be noted that throughout the drawings, like reference numerals identify like features. DETAILED DESCRIPTION

[0016] Figure 1 An aircraft engine 100 is shown, which is used for an aircraft of the type preferably provided for use in subsonic flight. The engine 100 generally includes (in serial flow communication): a propeller 120, through which ambient air is propelled and attached to a shaft 108; a compressor section 114, for pressurizing the air; a combustion chamber 116, in which the compressed air is mixed with fuel and ignited for generating an annular flow of hot combustion gases; and a turbine section 106, for extracting energy from the combustion gases. The propeller 120 converts the rotational motion of the shaft 108 from the engine 100 to provide propulsion, also known as thrust, for the aircraft. The propeller 120 includes two or more propeller blades 122. The blade angle of the propeller blades 122 can be adjusted to change the thrust. The blade angle can be referred to as a β angle, an angle of attack, or a blade pitch. The engine 100 can be implemented to include a single or multi-spool gas turbine engine, wherein the turbine section 106 is typically connected to the propeller 120 through a reduction gearbox (RGB). It should be appreciated that while engine 100 is a turboprop engine, the methods and systems described herein may be applicable to any other type of gas turbine engine, such as a turbofan engine, a turboshaft engine, or any other suitable aircraft engine.

[0017] refer to Figure 2A , illustrates a method for making a propeller (e.g. Figure 1The system 200 includes a solenoid 210 configured to feather the propeller 120 when the solenoid 210 is energized. The system 200 includes an electronic controller 220 connected to the solenoid 210 via a first electrical connection 201 for energizing the solenoid 210 to feather the propeller 120. The system 200 includes an auxiliary mechanism 230 connected to the solenoid 210 via a second electrical connection 202 for energizing the solenoid 210 to feather the propeller 120. The electronic controller 220 and the auxiliary mechanism 230 are independently operable to energize the solenoid 210 to feather the propeller 120. The first electrical connection 201 and the second electrical connection 202 are separate connections and are independent of each other. References to "feathering" the propeller 120 or adjusting the blade angle to "feather" the propeller 120 refer to directing the blades of the propeller 120 to a feathered position. In the feathered position, the propeller blades are positioned at an angle substantially parallel to the airflow over the propeller 120 so as to reduce forward drag on the aircraft. Although the engine 100 and propeller 120 are illustrated as being part of the system 200, it should be understood that this is for illustrative purposes only and that in some embodiments, the system 200 does not include the engine 100 and propeller 120.

[0018] Solenoid 210 is an electro-hydraulic actuator for adjusting the blade angle of propeller 120. Solenoid 210 is considered to be energized when at least one coil of solenoid 210 is energized. When the coil of solenoid 210 is energized, the solenoid valve is actuated to adjust the supply of hydraulic fluid to propeller 120 to drive the blade angle of propeller 120 toward the feathered position. Solenoid 210, when energized, can hydraulically bypass, for example, a pitch adjustment actuator (such as a pitch variation unit) that is used to fine-tune the propeller blade angle over the full range of propeller blade pitch. In some embodiments, solenoid 210 is a feathering solenoid, which can be used for routine feathering or automatic feathering operations. In some embodiments, solenoid 210 is a protection solenoid, which can be used when a propeller overspeed is detected or when the propeller blade angle is below the minimum allowed in-flight blade angle.

[0019] It should be appreciated that by connecting the auxiliary mechanism 230 to the same solenoid 210 to which the electronic controller 220 is connected, a dedicated emergency solenoid conventionally connected to the auxiliary mechanism 230 may be eliminated and the overall weight and / or cost of the propeller system may be reduced.

[0020] The electronic controller 220 may be any suitable electronic controller configured to energize the solenoid 210 for feathering the propeller 120. For example, the electronic controller 220 may close at least one switch to energize the solenoid 210 via the first electrical connection 201. The electronic controller 220 may energize the solenoid 210 in response to detecting that the propeller 120 should be driven to a feathered position. For example, before the engine 100 is shut down on-ground, the electronic controller 220 may command the propeller blade angle to the feathered position for routine feathering. For example, when the engine 100 has failed during takeoff, the electronic controller 220 may command the propeller blade angle to the feathered position for automatic feathering. When the rotational speed of the propeller exceeds a threshold, the electronic controller 220 may command the propeller blade angle to the feathered position to protect the propeller 120 from overspeeding. When the blade angle of the propeller 120 is below a minimum in-flight propeller blade angle, the electronic controller 220 may command the propeller blade angle to the feathered position. In some embodiments, electronic controller 220 energizes solenoid 210 in response to receiving a feather command from, for example, an engine or aircraft computer for detecting when propeller 120 should be driven to a feathered position. In some embodiments, electronic controller 220 is a propeller electronic controller.

[0021] In some embodiments, the auxiliary mechanism 230 is an emergency mechanism that can be actuated for emergency feathering of the propeller 120. The auxiliary mechanism 230 can be any suitable mechanism configured to energize the solenoid 210 for feathering the propeller 120. For example, the auxiliary mechanism 230 can close at least one switch to energize the solenoid 210 via the second electrical connection 202. The auxiliary mechanism 230 can include a non-electronic controller. For example, the auxiliary mechanism 230 can be a mechanical, pneumatic, hydraulic, or combination thereof mechanism. The auxiliary mechanism 230 can include a mechanical lever in the aircraft that, when actuated by a flight crew member (e.g., a pilot or other personnel), causes the solenoid 210 to be energized. For example, the mechanical lever can be operable to close at least one switch to energize the solenoid 210 when the mechanical lever is actuated. The mechanical lever can be considered a fire extinguishing handle. The auxiliary mechanism 230 can include an electronic controller. For example, a second electronic controller (i.e., separate from the first electronic controller 220) may be operable to close at least one switch to energize the solenoid 210 when an actuator (e.g., a button, a lighted button, a switch, a dial, a knob, any other suitable interface, or the like) connected to the second electronic controller is actuated. The second electronic controller may be an aircraft computer.

[0022] In some embodiments, the auxiliary mechanism 230 is connected to the electronic controller 220 via the connection 203 and is configured to provide an indication to the electronic controller 220 when the auxiliary mechanism 230 is actuated. In some embodiments, the electronic controller 220 is configured to disable energization of the solenoid 210 by the electronic controller 220 in response to receiving the indication. For example, the electronic controller 220 may disable energization of the solenoid 210 for automatic feathering, routine feathering, propeller overspeed protection, minimum in-flight propeller blade angle, and / or the like. In some embodiments, the electronic controller 220 is configured to disable fault detection of at least one switch for energizing the solenoid 210 via the first electrical connection 201 in response to receiving the indication. Fault detection of the electronic controller 220 may evaluate whether the electronic controller 220 commands energization of the solenoid 210. If the electronic controller 220 does not command energization of the solenoid 210 and the solenoid 210 is energized, the electronic controller 220 may detect a fault of the at least one switch. When a fault is detected, the fault may be output to a display device to indicate the fault. The auxiliary mechanism 230 may be directly or indirectly connected to the electronic controller 220 for providing the indication. The indication may be provided as an analog or digital signal.

[0023] refer to Figure 2B In some embodiments, the electronic controller 220 and the auxiliary mechanism 230 each include two switches. In some embodiments, the electronic controller 220 is configured to operate (i.e., open and close) a high-side switch 222 and a low-side switch 224. When both the high-side switch 222 and the low-side switch 224 are closed, the coil 211 of the solenoid 210 is energized. The high-side switch 222 provides a power source (e.g., a 28 V source or any other suitable voltage) to the first electrical connection 201 when closed, and the low-side switch 224 provides a ground connection to the first electrical connection 201 when closed. If either (or both) of the switches 222, 224 are opened, the solenoid 210 will not be energized via the first electrical connection 201. One of the switches 222, 224 may be held in a closed position by default, and the electronic controller 220 may be configured to operate the other of the switches 222, 224 to energize the solenoid 210. Alternatively, in some embodiments, the electronic controller 220 includes a high-side switch or a low-side switch operable to energize the solenoid 210 .

[0024] In some embodiments, the auxiliary mechanism 230 is configured to close the high-side switch 232 and the low-side switch 234 when actuated. When both the high-side switch 232 and the low-side switch 234 are closed, the coil 211 of the solenoid 210 is energized. As shown, the auxiliary mechanism 230 is connected to the same solenoid coil 211 to which the electronic controller 220 is connected. The high-side switch 232 provides a power source (e.g., a 28 V source or any other suitable voltage) to the second electrical connection 202 when closed, and the low-side switch 234 provides a ground connection to the second electrical connection 202 when closed. If either (or both) of the switches 232, 234 are open, the coil 211 of the solenoid 210 will not be energized via the second electrical connection 202. If either (or both) of the switches 222, 224 are open, the coil 211 of the solenoid 210 can be energized via the second electrical connection 202 by closing the switches 232 and 234. One of the switches 232, 234 may be held in a closed position by default, and the auxiliary mechanism 230 may be configured to close the other of the switches 222, 224 when actuated. Alternatively, in some embodiments, the auxiliary mechanism 230 includes a high-side switch or a low-side switch operable to energize the solenoid 210. In some embodiments, the switches 232, 234 can be simultaneously operated by a single control device (also referred to as a "gang switch") to energize the solenoid 210.

[0025] In some embodiments, for example Figure 2B , the auxiliary mechanism 230 is connected to the electronic controller 220 via the aircraft computer 240. The aircraft computer 240 can monitor the auxiliary mechanism 230 to detect when the auxiliary mechanism 230 is actuated. For example, the aircraft computer 240 can monitor at least one of the switches 232, 234 to detect when the mechanism 230 is actuated. Alternatively, the auxiliary mechanism 230 can provide an indication to the aircraft computer 240 when it is actuated. When the auxiliary mechanism 230 is actuated, the indication that the auxiliary mechanism 230 is actuated can be provided from the aircraft computer 240 to the electronic controller 220. In some embodiments, the auxiliary mechanism 230 includes the aircraft computer 240.

[0026] Reference numeral 250 illustrates that the electronic controller 220 and the solenoid 210 are positioned in an area subject to a possible fire (hereinafter "fire area"). Since emergency feathering may be required when a fire is present, the hardware and / or components related to emergency feathering positioned in the fire area 250 may be made of fireproof or fire-resistant materials. Therefore, in some embodiments, the second electrical connection 202 is a fireproof or fire-resistant connection. In some embodiments, the connection 203 between the aircraft computer 240 and the electronic controller 220 is a fireproof or fire-resistant connection.

[0027] refer to Figure 2C In some embodiments, the electronic controller 220 includes two or more channels, such as channels A and B. Channels A and B are redundant channels, and one of the channels (e.g., channel A) is selected to be active while the other channel remains in standby (e.g., channel B). When a channel is active, the channel can be used to energize the solenoid 210 to feather the propeller 120, and when the channel is in standby, the channel is not used to energize the solenoid 210 to feather the propeller 120. When a channel is in standby, the channel is functional and can take over control when needed. If it is determined that the currently active channel is faulty or inoperable, the currently active channel can be inactivated and the channel in standby can be activated. Similarly, if during operation, the input to the currently active channel is erroneous or non-existent, the currently active channel can be inactivated and one of the channels in standby can be activated.

[0028] like Figure 2C As shown in FIG. 1 , each channel A, B of the electronic controller 220 includes a high-side switch 222 A or 222 B and low side switch 224 A or 224 B Each channel A, B is related to Figure 2B The electronic controller 220 operates the high side switch 222 in a manner similar to that described above. A or 222 B and low side switch 224 A or 224 B The high-side switch 222 in channel A A and low side switch 224 A When both are closed, the first coil 211 of the solenoid 210 is energized via the first electrical connection 201 to energize the solenoid 210. The high side switch 222 in channel B B and low side switch 224 B When both are closed, the second coil 212 of the solenoid 210 is energized via the separate electrical connection 205 to energize the solenoid 210. Alternatively, in some embodiments, each channel A, B includes a high-side switch or a low-side switch operable to energize the solenoid 210.

[0029] In some embodiments, Figure 2CAs shown in FIG. 1 , the solenoid 210 is configured so that only one of the two coils 211, 212 needs to be energized to feather the propeller 120. In some embodiments, the second electrical connection 202 connects the auxiliary mechanism 230 to one of the two coils 211, 212 of the solenoid 210, which is also connected to one of the channels of the electronic controller 220. In some embodiments, the solenoid 210 includes a first connector 261. A and the second connector 262. The first connector 261 A Channel A of the electronic controller 220 is connected to the first coil 211, and a second connector 262 connects the auxiliary mechanism 230 to the first coil 211. Another connector 261 B It can be used to connect channel B of the electronic controller 220 to the second coil 212. Although the auxiliary mechanism 230 is shown connected to the first coil 211, in other embodiments, the auxiliary mechanism 230 can be connected to the second coil 212. Alternatively, in some embodiments, the mechanism 230 is connected to both coils 211, 212 of the solenoid 210.

[0030] like Figure 2C As shown in , in some embodiments, the auxiliary mechanism 230 is connected to each of the two channels A, B to provide an indication that the auxiliary mechanism 230 is actuated. The first aircraft computer 241 can obtain the indication that the auxiliary mechanism 230 is actuated. The indication that the auxiliary mechanism 230 is actuated can be provided from the first aircraft computer 241 to one of the channels of the electronic controller 220 (e.g., channel A). In some embodiments, the indication that the auxiliary mechanism 230 is actuated can be provided from the first aircraft computer 241 to the second aircraft computer 242, and the second aircraft computer 242 provides the indication to another channel of the electronic controller 220 (e.g., channel B). In some embodiments, the second aircraft computer 242 can obtain the indication from the auxiliary mechanism 230 and provide the indication to one of the channels (e.g., channel B). Alternatively, in some embodiments, a single aircraft computer can be used to provide the indication to both channels A, B.

[0031] Diode 225 A or 225 B A high side switch 222 can be positioned in each channel A and B A or 222 B Between the solenoid 210 and the diode 225 is used for current reverse flow protection. A The electric power from the auxiliary mechanism 230 may be prevented from damaging the electronic controller 220. Similarly, the diode 235 may be used for current reverse flow protection to prevent the electric power from the electronic controller 220 from damaging the auxiliary mechanism 230. Other suitable devices and / or mechanisms for reverse flow protection may be used.

[0032] refer to Figure 3A , a flow chart of a method 300 for feathering a propeller, such as propeller 120, is illustrated. At step 302, upon receiving a first request to energize the solenoid from electronic controller 220 via first electrical connection 201 to solenoid 210, solenoid 210 is energized to feather propeller 120. At step 304, upon receiving a second request to energize the solenoid from auxiliary mechanism 230 via second electrical connection 202 to solenoid 210, solenoid 210 is energized to feather propeller 120. Electronic controller 220 and auxiliary mechanism 230 are operable to energize solenoid 210 independently of each other. Second electrical connection 202 is independent of first electrical connection 201. In some embodiments, solenoid 210 includes two coils, and energizing solenoid 210 via second electrical connection 202 at step 304 includes energizing one of the two coils via second electrical connection 202. In some embodiments, at step 306, method 300 includes providing an indication to electronic controller 220 when auxiliary mechanism 230 is actuated. The indication is provided from the auxiliary mechanism 230 and may be provided via an aircraft computer (e.g., aircraft computers 240, 241, and / or 242). In some embodiments, the electronic controller 220 includes two channels A, B, and the indication is provided to each of the two channels A, B. In some embodiments, at step 308, the method 300 includes the electronic controller 220 disabling energization of the solenoid 210 by the electronic controller 220 in response to receiving the indication. In some embodiments, at step 310, the method 300 includes the electronic controller 220 disabling fault detection of at least one switch used to energize the solenoid 210 via the first electrical connection 201 in response to receiving the indication.

[0033] refer to Figure 3B, a flow chart of method 350 is illustrated. At step 352, solenoid 210 is connected to electronic controller 220 via first electrical connection 201. Solenoid 210 is configured to feather propeller 120 when solenoid 210 is energized by electronic controller 220 via first electrical connection 201. At step 352, solenoid 210 is connected to auxiliary mechanism 230 via second electrical connection 202. Solenoid 210 is configured to feather propeller 120 when solenoid 210 is energized by auxiliary mechanism 230 via second electrical connection 202. Second electrical connection 202 is independent of first electrical connection 201. In some embodiments, at step 354, auxiliary mechanism 230 is connected to electronic controller 220 via third connection 203. Third connection 203 may be used to provide an indication when auxiliary mechanism 230 is actuated. In some embodiments, auxiliary mechanism 230 is connected to electronic controller 220 via at least one aircraft computer 240, 241, and / or 242. In some embodiments, the solenoid 210 includes two coils 211, 212, and connecting the solenoid 210 to the auxiliary mechanism 230 includes connecting one of the two coils 211, 212 to the auxiliary mechanism 230 via the second electrical connection 202. In some embodiments, the solenoid 210 includes two coils 211, 212, and connecting the solenoid 210 to the electronic controller 220 includes connecting one of the two coils 211, 212 (e.g., the first coil 211) to a first channel A of the electronic controller 220 and connecting the other of the two coils 211, 212 (e.g., the second coil 212) to a second channel B of the electronic controller 220.

[0034] refer to Figure 4 , illustrating an example of a computing device 400. The electronic controller 220 may be implemented with one or more computing devices 400. In some embodiments, each channel A, B of the electronic controller 220 may be implemented by a separate computing device 400. The computing device 400 includes a processing unit 412 and a memory 414, in which the memory 414 has stored therein computer executable instructions 416. The processing unit 412 may include any suitable device configured to implement the method 300 and / or 350, so that the instructions 416, when executed by the computing device 400 or other programmable device, may cause the functions / actions / steps to be performed as part of the method 300 and / or 350 to be performed as described herein. The processing unit 412 may include, for example, any type of general purpose microprocessor or microcontroller, a digital signal processing (DSP) processor, a central processing unit (CPU), an integrated circuit, a field programmable gate array (FPGA), a reconfigurable processor, other suitably programmed or programmable logic circuits, or any combination thereof.

[0035] The memory 414 may include any suitable known or other machine-readable storage medium. The memory 414 may include a non-transitory computer-readable storage medium, such as, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared or semiconductor system, device, or device, or any suitable combination of the above. The memory 414 may include a suitable combination of any type of computer memory located inside or outside the device (e.g., random access memory (RAM), read-only memory (ROM), compact disk read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM) and electrically erasable programmable read-only memory (EEPROM), ferroelectric RAM (FRAM), or the like). The memory 414 may include any storage component (e.g., device) suitable for retrievably storing machine-readable instructions 416 executable by the processing unit 412. Note that the computing device 400 can be implemented as part of a full authority digital engine control device (FADEC) or other similar device (including an electronic engine control device (EEC), an engine control unit (EUC), an electronic propeller control device, a propeller control unit, and the like).

[0036] The methods and systems for feathering a propeller described herein may be implemented in a high-level procedural or object-oriented programming or scripting language or a combination thereof to communicate with or assist in the operation of a computer system, such as computing device 400. Alternatively, the methods and systems for feathering a propeller may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the methods and systems for feathering a propeller may be stored on a storage medium or device, such as a ROM, a magnetic disk, an optical disk, a flash drive, or any other suitable storage medium or device. When the storage medium or device is read by the computer to perform the processes described herein, the program code may be readable by a general or special purpose programmable computer for configuring and operating the computer. Embodiments of the methods and systems for feathering a propeller may also be considered to be implemented by a non-transitory computer-readable storage medium having a computer program stored thereon. The computer program may include computer-readable instructions that cause a computer, or more specifically a processing unit 412 of computing device 400, to operate in a specific and predefined manner to perform the functions described herein, such as those described in methods 300 and / or 350.

[0037] Computer executable instructions can take many forms, including program modules that are executed by one or more computers or other devices. Typically, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. Typically, the functionality of program modules can be combined or distributed as desired in various embodiments.

[0038] The above description is meant to be exemplary only, and those skilled in the art will recognize that changes may be made to the described embodiments without departing from the scope of the disclosed invention. From a review of this disclosure, it will be apparent to those skilled in the art that there are other modifications that fall within the scope of the invention.

[0039] Various aspects of the method and system for feathering a propeller may be used alone, in combination, or in various arrangements not specifically discussed in the embodiments described above, and are therefore not limited in their application to the details and arrangements of components set forth in the foregoing description or illustrated in the accompanying drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments. Although particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made in the broader aspects of the invention without departing from the invention. The scope of the following claims should not be limited by the embodiments set forth in the examples, but should be given the broadest reasonable interpretation consistent with the description as a whole.

Claims

1. A system comprising: a solenoid configured to feather the propeller when the solenoid is energized; an electronic controller connected to the solenoid via a first electrical connection, the electronic controller commanding feathering of the propeller by energizing the solenoid via the first electrical connection; as well as a solenoid activating mechanism operable independently of the electronic controller and connected to the solenoid via a second electrical connection, the solenoid activating mechanism having a mechanical element movable between a first position and a second position, the mechanical element causing the solenoid to be energized via the second electrical connection when in the second position, the second electrical connection being independent of the first electrical connection, wherein the solenoid energizing mechanism is connected to the electronic controller and is configured to provide an indication to the electronic controller when the solenoid is energized via the second electrical connection, Wherein the electronic controller is configured to inhibit energization of the solenoid by the electronic controller in response to receiving the indication. 2 . The system of claim 1 , wherein the electronic controller is configured to disable fault detection of at least one switch used to energize the solenoid through the first electrical connection in response to receiving the indication.

3. The system of any one of claims 1 to 2, wherein the solenoid actuation mechanism is connected to the electronic controller via an aircraft computer.

4. The system of any one of claims 1 to 2, wherein the electronic controller comprises two channels, and the solenoid energizing mechanism is connected to each of the two channels to provide the indication thereto.

5. The system of any one of claims 1 to 2, wherein the solenoid comprises two coils, and the second electrical connection connects the solenoid energizing mechanism to one of the two coils.

6. The system of any one of claims 1 to 2, wherein the solenoid energizing mechanism is configured to close a high-side switch and a low-side switch when actuated, the solenoid being energized when both the high-side switch and the low-side switch are closed.

7. The system of any one of claims 1 to 2, wherein the solenoid energizing mechanism comprises a mechanical lever operable to close at least one switch to energize the solenoid.

8. A method of feathering a propeller, the method comprising: energizing the solenoid to feather the propeller upon receiving a first request to energize the solenoid from an electronic controller via a first electrical connection to the solenoid; as well as energizing the solenoid to feather the propeller upon receiving a second request to energize the solenoid from a solenoid energizing mechanism operable independently of the electronic controller via a second electrical connection to the solenoid, the solenoid energizing mechanism having a mechanical element movable between a first position and a second position, the mechanical element in the second position causing the solenoid to be energized via the second electrical connection, the second electrical connection being independent of the first electrical connection, Further comprising providing an indication to the electronic controller when the solenoid is energized via the second electrical connection, and further comprising disabling energization of the solenoid by the electronic controller in response to the electronic controller receiving the indication.

9. The method of claim 8, further comprising disabling fault detection of at least one switch used to energize the solenoid through the first electrical connection in response to the electronic controller receiving the indication.

10. The method of any one of claims 8 to 9, wherein providing the indication comprises providing the indication via an aircraft computer.

11. The method of any one of claims 8 to 9, wherein the electronic controller comprises two channels, and wherein providing the indication comprises providing the indication to each of the two channels.

12. The method of any one of claims 8 to 9, wherein the solenoid comprises two coils, and wherein energizing the solenoid through the second electrical connection comprises energizing one of the two coils through the second electrical connection.

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