Aircraft system and method

1. A method of aircraft tire maintenance comprising:

receiving data of a plurality of pressure and temperature measurements, each of the plurality of pressure and temperature measurements having an associated time stamp;

determining stable points in the plurality of pressure and temperature measurements;

wherein the stable points are identified by:

a pair of measurement points between which both the gradient of pressure against time and the gradient of temperature against time have changed by less than 2% over a predetermined period of time,

using the stable points for determining tire maintenance; and

responsive to determining of the tire maintenance reinflating or replacing the tire.

2. A method according to claim 1 , wherein stable points are points between which pressure has changed by less than 5 psi (34.5 kPa) and temperature has changed by less than 5° C. over a predetermined period of time.

3. A method according to claim 1 , further comprising normalizing the pressure measurement at the stable points to a pressure at a reference temperature using the temperature data associated with pressure measurement, thereby to generate normalized stable pressure data.

4. A method according to claim 3 , wherein the using the stable points for tire maintenance comprises fitting a trend line to the normalized stable pressure data and providing an indication to take a maintenance action based on the trend line.

5. A method according to claim 4 , comprising providing an indication to take maintenance action if the trend line indicates a deflation rate of greater than or equal to 5% per day.

6. A method according to claim 4 , comprising providing an indication to take maintenance action if the trend line indicates inflation independent of an inflation event.

7. A method according to claim 4 , comprising providing an indication to take maintenance action if the trend line indicates that the pressure will be below a predetermined threshold within a predetermined time period from a current time.

8. A method according to claim 7 , wherein the predetermined time period corresponds to the time between tire pressure measurements defined in the aircraft's Maintenance Planning Document.

9. A method according to claim 4 , further comprising causing a maintenance action based on the trend line.

10. A processing system configured to implement the method of claim 1 .

11. A tire monitoring device comprising a processing system according to claim 10 .

12. A system comprising:

a processing system according to claim 10 ; and

a plurality of tire monitoring devices, each comprising:

a processor;

a pressure sensor;

a temperature sensor;

a time source;

a communication interface; and

a storage;

wherein the storage comprises instructions that, when executed by the processor, cause the tire monitoring device to:

measure pressure and temperature, using the pressure sensor and the temperature sensor, at predetermined intervals;

store the measurements in the storage with an associated time stamp from the time source; and

provide a plurality of the stored measurements to the processing system via the communication interface.

13. A non-transitory computer-readable storage medium storing instructions that, when executed by a processing system, instruct the processing system to perform a method comprising:

receiving data of a plurality of pressure and temperature measurements, each of the plurality of pressure and temperature measurements having an associated time stamp;

determining stable points in the plurality of pressure and temperature measurements;

wherein the stable points are identified by

a pair of measurement between which both the gradient of pressure against time and the gradient of temperature against time have changed by less than 2% over a predetermined period of time;

using the stable points for determining tire maintenance; and

responsive to determining of the tire maintenance causing or scheduling reinflating or replacing the tire.