Abstract: An aircraft turbomachine (100) comprising a first channel (200) putting into communication the high-pressure compressor (30) and a high-pressure turbine (50), a second channel (400) putting into communication the high-pressure compressor and a low-pressure turbine (60), the first channel being equipped with a valve (600), a third channel (700) being in selective communication with the first channel via the valve, the third channel being in communication with the low-pressure turbine, the valve having a first configuration in which air circulation in the first channel is allowed and prohibited in the third channel, and a second configuration in which air circulation of the first channel is diverted to the third channel, a control device (800) being configured to determine an air pressure of the low-pressure turbine and command the valve to cause it to transition from the first configuration to the second configuration depending on the determined pressure.