An aircraft comprising: - a main engine capable of providing bleed air supply, - an auxiliary power unit housed within an APU compartment, and having an APU bleed valve configured to control the bleed air passage into the auxiliary power unit, - an APU bleed air duct connecting the main engine with the auxiliary power unit to provide a bleed air passage, characterized in that the aircraft additionally comprises a bleed air heating system for the APU compartment that comprises: - an auxiliary pipeline tapped to the APU bleed air duct and connected to the APU compartment, - an auxiliary pipeline valve configured to control the bleed air discharged from the auxiliary pipeline into the APU compartment, - a temperature sensor placed to sense the temperature of the APU compartment, and - a temperature controller coupled to the temperature sensor to receive the sensed the temperature, and adapted to establish a heating operation mode when the sensed temperature falls below a minimum temperature threshold value, and a standby operation mode when the sensed temperature surpasses a maximum temperature threshold value, - wherein, when the heating operation mode is established, the temperature controller is adapted to: - command the closing of the APU bleed valve for avoiding the bleed air enter into the auxiliary power unit, - activate the bleed air supply of the main engine, and - activate the opening of the auxiliary pipeline valve for conducting bleed air from the main engine towards the APU compartment, to heat said APU compartment, - and wherein, when the standby operation mode is established, the temperature controller is adapted to: - deactivate the bleed air supply of the main engine, - activate the closing of the auxiliary pipeline valve to stop heating the APU compartment, and - command the opening of the APU bleed valve to allow the bleed air enter into the auxiliary power unit. - a main engine capable of providing bleed air supply, - an auxiliary power unit housed within an APU compartment, and having an APU bleed valve configured to control the bleed air passage into the auxiliary power unit, - an APU bleed air duct connecting the main engine with the auxiliary power unit to provide a bleed air passage, - an auxiliary pipeline tapped to the APU bleed air duct and connected to the APU compartment, - an auxiliary pipeline valve configured to control the bleed air discharged from the auxiliary pipeline into the APU compartment, - a temperature sensor placed to sense the temperature of the APU compartment, and - a temperature controller coupled to the temperature sensor to receive the sensed the temperature, and adapted to establish a heating operation mode when the sensed temperature falls below a minimum temperature threshold value, and a standby operation mode when the sensed temperature surpasses a maximum temperature threshold value, - wherein, when the heating operation mode is established, the temperature controller is adapted to: - command the closing of the APU bleed valve for avoiding the bleed air enter into the auxiliary power unit, - activate the bleed air supply of the main engine, and - activate the opening of the auxiliary pipeline valve for conducting bleed air from the main engine towards the APU compartment, to heat said APU compartment, - command the closing of the APU bleed valve for avoiding the bleed air enter into the auxiliary power unit, - activate the bleed air supply of the main engine, and - activate the opening of the auxiliary pipeline valve for conducting bleed air from the main engine towards the APU compartment, to heat said APU compartment, - and wherein, when the standby operation mode is established, the temperature controller is adapted to: - deactivate the bleed air supply of the main engine, - activate the closing of the auxiliary pipeline valve to stop heating the APU compartment, and - command the opening of the APU bleed valve to allow the bleed air enter into the auxiliary power unit. - deactivate the bleed air supply of the main engine, - activate the closing of the auxiliary pipeline valve to stop heating the APU compartment, and - command the opening of the APU bleed valve to allow the bleed air enter into the auxiliary power unit.