A safety apparatus for containing a release of energy from a tension stud of a rotor assembly, the safety apparatus includes an elongate member defining a longitudinal axis and at least two arms projecting away from the longitudinal axis of the elongate member. In use, in a first orientation, the elongate member is configured to be connected to a tool apparatus for applying a load energy to the tension stud and the at least two arms of the safety apparatus are configured to overlap with at least part of the tool apparatus in the direction of the longitudinal axis of the elongate member to contain the release of energy therebetween.

Systems and methods for shutting down a gas turbine engine in response to a severe mechanical failure include determining a rate of change of one or more process conditions. If the rate of change of the one or more process conditions exceeds a respective predetermined failure threshold, a potential severe mechanical failure of the gas turbine engine may be determined. Steps may be taken to confirm the potential severe mechanical failure of the gas turbine engine. In response, an engine restart is prevented.

Systems and methods for shutting down a gas turbine engine in response to a severe mechanical failure include determining a rate of change of one or more process conditions. If the rate of change of the one or more process conditions exceeds a respective predetermined failure threshold, a potential severe mechanical failure of the gas turbine engine may be determined. Steps may be taken to confirm the potential severe mechanical failure of the gas turbine engine. In response, an engine restart is prevented.

According to an aspect, a bowed rotor sensor system for a gas turbine engine is provided. The bowed rotor sensor system includes a bowed rotor sensor operable to transmit a sensing field in an observation region and receive a signal indicative of a gap between an air seal and a blade tip within the gas turbine engine. The bowed rotor sensor system also includes a controller operable to monitor a plurality of gap data from the bowed rotor sensor indicative of the gap between the air seal and the blade tip of a plurality of blades passing through the observation region and determine a bowed rotor status of the gas turbine engine based on the gap data.

According to an aspect, a bowed rotor sensor system for a gas turbine engine is provided. The bowed rotor sensor system includes a bowed rotor sensor operable to transmit a sensing field in an observation region and receive a signal indicative of a gap between an air seal and a blade tip within the gas turbine engine. The bowed rotor sensor system also includes a controller operable to monitor a plurality of gap data from the bowed rotor sensor indicative of the gap between the air seal and the blade tip of a plurality of blades passing through the observation region and determine a bowed rotor status of the gas turbine engine based on the gap data.

A method of reducing rotor bow in a high pressure rotor of a gas turbine engine that has in axial flow a low pressure rotor and a high pressure rotor. The method involves storing bleed air from the gas turbine engine when the engine is running to provide stored pneumatic energy; and using that stored pneumatic energy after the engine has been shut-down to rotate the high pressure rotor at a speed and for a duration that reduces rotor bow. A gas turbine engine wherein rotor bow in the high pressure rotor after engine shut-down has been reduced by carrying out the aforesaid method is also disclosed.

A method of reducing rotor bow in a high pressure rotor of a gas turbine engine that has in axial flow a low pressure rotor and a high pressure rotor. The method involves storing bleed air from the gas turbine engine when the engine is running to provide stored pneumatic energy; and using that stored pneumatic energy after the engine has been shut-down to rotate the high pressure rotor at a speed and for a duration that reduces rotor bow. A gas turbine engine wherein rotor bow in the high pressure rotor after engine shut-down has been reduced by carrying out the aforesaid method is also disclosed.

A system and method for rotor bow mitigation for a gas turbine engine are provided. An elapsed time since a shutdown of the engine and an idle operation time of the engine prior to the shutdown are determined. A rotor bow mitigation period is determined based on the elapsed time and the idle operation time and, prior to initiating a start sequence of the engine, the engine is motored for a duration of the rotor bow mitigation period.

A system and a method for detecting a shaft shear event in a gas turbine engine are disclosed. The system comprises a sensor configured to detect a shaft shear force exerted by a shaft on a support structure supporting the shaft where the shaft shear force is indicative of shearing of the shaft. The system also comprises a controller operatively coupled to the sensor and configured to initiate a shutdown of the gas turbine engine in response to the detection of the shaft shear force by the sensor.

A control apparatus for a gas-turbine aeroengine having discriminator that discriminates normality of a low-pressure turbine rotational speed sensor adapted to detect the low-pressure turbine rotational speed and a high-pressure turbine rotational speed controller that establish a first value as an upper limit value of a high-pressure turbine rotational speed and controls the high-pressure turbine rotational speed based on the established upper limit value, and is configured to change the upper limit value to a second value lower than the first value when the low-pressure turbine rotational speed sensor is discriminated not to be normal, whereby engine output (thrust) determined by the low-pressure turbine rotational speed can be controlled to a desired value while restraining the high-pressure turbine rotational speed to not greater than the first value, and low-pressure turbine overspeed at the time of a mishap such as engine fan blade breakage can be reliably prevented.