Abstract: Disclosed is an aircraft accessory drive system comprising: a drive shaft configured to provide a drive input; a critical accessory directly coupled to the drive shaft so as to be directly driven by the drive shaft; a parasitic drive system configured to transmit drive input from the drive shaft to one or more less critical accessories, wherein the parasitic drive system comprises a torque limiter configured to decouple the parasitic drive system from the drive shaft and the critical accessory in response to a jam affecting the parasitic drive system or one or more of the less critical accessories. Also disclosed are a gas turbine engine comprising an aircraft accessory drive system, and an aircraft comprising an aircraft accessory drive system.

Abstract: A method of operating an aircraft electrical power distribution system comprises determining a measure of ambient pressure; and setting a target operating voltage in accordance with the measure of ambient pressure. The method further comprises controlling the operating voltage in accordance with the set target operating voltage. The target operating voltage may refer to a distribution voltage of the aircraft. An aircraft electrical power distribution system is also disclosed, comprising: a sensor configured to determine a measure of ambient pressure; a controller configured to set a target operating voltage in accordance with the measure of ambient pressure, and a voltage regulator configured to regulate the operating voltage in accordance with the set target value.

Abstract: A method of operating an aircraft electrical power distribution system comprises determining a measure of ambient pressure; and setting a target operating voltage in accordance with the measure of ambient pressure. The method further comprises controlling the operating voltage in accordance with the set target operating voltage. The target operating voltage may refer to a distribution voltage of the aircraft. An aircraft electrical power distribution system is also disclosed, comprising: a sensor configured to determine a measure of ambient pressure; a controller configured to set a target operating voltage in accordance with the measure of ambient pressure, and a voltage regulator configured to regulate the operating voltage in accordance with the set target value.