There is provided a blade angle feedback system for an aircraft-bladed rotor rotatable about a longitudinal axis and having an adjustable blade pitch angle. A feedback device is coupled to rotate with the rotor and to move along the axis with adjustment of the blade pitch angle. The feedback device comprises a body having position marker(s) embedded therein, the body made of a first material having a first magnetic permeability and the position marker(s) comprising a second material having a second magnetic permeability greater than the first. Sensor(s) are positioned adjacent the feedback device and configured for producing, as the feedback device rotates about the axis, sensor signal(s) in response to detecting passage of the position marker(s). A control unit is communicatively coupled to the sensor(s) and configured to generate a feedback signal indicative of the blade pitch angle in response to the sensor signal(s) received from the sensor(s).

A method of controlling a propeller assembly, having a blade, piston end cap, and piston, with a pitch control unit, having a transfer bearing and a blade angle unit, the method comprising: axially moving a transfer tube relative to and circumscribing the transfer bearing, and sensing an axial movement of the transfer tube with the blade angle unit.

A calibration system for aircraft control surface actuation includes an inclinometer coupleable to an aircraft control surface. The inclinometer is configured to provide measurement data of an inclination value corresponding to an angle at which the surface is deflected. The system includes an adapter with a wireless transmitter module and an interface connector connected to the inclinometer. The adapter is configured to receive and wirelessly transmit the measurement data. The system includes a wireless receiver device and a computing device connected thereto to receive the measurement data. The computing device is configured to determine if the inclination value differs by more than a predetermined amount from a directed deflection angle for the surface. The computing device is also configured to communicate an adjustment amount to a controller configured to direct deflection of the surface, based on the difference between the measured inclination value and the directed deflection angle.

Methods and systems for validating a propeller control unit associated with a propeller having blades are provided. Actuation of a control valve of the propeller control unit is commanded to alter a pitch angle of the blades. One of an actual pitch angle of the blades and an actual rotational speed of the propeller is determined after a predetermined time delay has elapsed. The one of the actual pitch angle of the blades and the actual rotational speed of the propeller is compared to a corresponding one of a pitch angle threshold and a rotational speed threshold, the pitch angle threshold and the rotational speed threshold based on a commanded pitch angle. A warning signal is issued in response to determining one of the actual pitch angle failing to meet the pitch angle threshold and the actual rotational speed failing to meet the rotational speed threshold.

A sensor signal produced by a sensor as a feedback device rotates with a propeller about an axis and moves along the axis with adjustment of a blade angle of the propeller is received, the sensor signal indicative of a rotational speed and of the blade angle of the propeller. From the sensor signal, it is determined whether the rotational speed is within a predetermined range of a reference speed and an expected change in the blade angle has occurred in response to a command to adjust the blade angle to maintain the rotational speed at the reference speed. In response to determining that the rotational speed is within the predetermined range of the reference speed and the expected change in the blade angle has failed to occur in response to the command, inoperable movement of the feedback device along the axis is determined and an alert is output.

A failure detection method and system for a propeller control unit coupled to a propeller are provided. An actual value of a blade angle and/or a rotational speed of the propeller are obtained. A comparison between the actual value and a threshold is performed. In response to determining, based on the comparison, that the actual value exceeds the threshold, the propeller control unit is caused to adjust the blade angle to bring the blade angle and/or the rotational speed towards the threshold. A subsequent actual value of the blade angle and/or the rotational speed is obtained. From the subsequent value, it is determined whether the blade angle and/or the rotational speed has been brought towards the threshold. In response to determining that the blade angle and/or the rotational speed has failed to be brought towards the threshold, failure of the propeller control unit is detected and an alert is output.

A sensor signal comprising a first signal pulse having a first voltage amplitude and a second signal pulse having a second voltage amplitude greater than or substantially equal to the first voltage amplitude is obtained from a sensor positioned adjacent a feedback device coupled to rotate with an aircraft-bladed rotor about a longitudinal axis and to move along the axis with adjustment of the rotor's blade pitch angle. The feedback device comprises a reference feature configured to generate the second signal pulse and varying detectable feature(s) configured to generate the first signal pulse and to cause a change in the first voltage amplitude as a function of an axial position of the feedback device along the axis. A voltage ratio is determined based on the first voltage amplitude and the second voltage amplitude, and the axial position of the feedback device is determined from the voltage ratio.

A feedback device for use in a gas turbine engine, and methods and systems for controlling a pitch for an aircraft-bladed rotor, are provided. The feedback device is composed of a circular disk and a plurality of position markers. The circular disk is coupled to rotate with a rotor of the gas turbine engine, to move along a longitudinal axis of the rotor, and has first and second opposing faces defining a root surface that extends between and circumscribes the first and second faces. The plurality of position markers extend radially from the root surface and are circumferentially spaced around the circular disk. The position markers have a top surface elevated with respect to the root surface and opposing first and second side surfaces. The side surfaces of the position markers have a curved concave profile extending toward the root surface.

An aircraft propeller control system for an aircraft propeller with adjustable blade angle has a blade angle feedback ring and a sensor, one of which is mounted for rotation with the propeller. The blade angle feedback ring moves longitudinally along with adjustment of the blade angle and has position markers circumferentially spaced apart at distances that vary along a longitudinal axis. The sensor is positioned adjacent the feedback ring for producing signals indicative of passage of the position markers. Intervals between signals are indicative of circumferential distances between position markers. A controller measures longitudinal position of the feedback ring based on the intervals and is configured to produce a warning signal if the longitudinal position is outside a first threshold range.

A propeller control system for an aircraft propeller rotatable about a longitudinal axis and having an adjustable blade angle is provided. A blade angle feedback ring is coupled to the propeller to rotate with the propeller and to move along the longitudinal axis along with adjustment of the blade angle. The feedback ring includes position markers spaced around its circumference. A sensor is positioned adjacent the feedback ring for producing signals indicative of passage of the position markers. A controller is in communication with the sensor, and is configured for: measuring a distance between the position markers, wherein the distance is representative of a longitudinal position of the feedback ring; determining whether a value representative of the longitudinal position is within a first threshold range; and when the value is within the first threshold range, storing the value as a calibration value associated with the blade angle feedback ring.