System and method for pitot tube blockage detection

1. A method of detecting blockage of a pitot tube, comprising:

measuring a pitot tube temperature via one or more temperature sensors disposed inside a pitot tube;

measuring an outside ambient air temperature;

selecting a minimum measured pitot tube temperature threshold based on the measured outside ambient air temperature;

comparing the measured pitot tube temperature to the minimum measured pitot tube temperature threshold for the measured outside ambient air temperature; and

determining the pitot tube has a blockage condition when the measured pitot tube temperature is below the minimum measured pitot tube temperature threshold.

2. The method of claim 1 , further comprising:

determining whether a pitot tube heater is operational; and

selecting the minimum measured pitot tube temperature threshold based on the measured outside ambient air temperature and an operational status of the pitot tube heater.

3. The method of claim 1 , further comprising alerting a flight crew regarding the blockage condition.

4. The method of claim 3 , wherein the alert is a visual and/or aural alert.

5. The method of claim 1 , wherein the minimum measured pitot tube temperature threshold is obtained from a temperature calibration database.

6. The method of claim 1 , wherein measuring a pitot tube temperature comprises measuring three of more pitot tube temperatures via three or more temperature sensors located at three or more longitudinal locations of the pitot tube.

7. The method of claim 6 , wherein the three or more temperature sensors are located at three or more circumferential locations of the pitot tube.

8. A pitot tube system, comprising:

a pitot tube; and

a blockage detection system operably connected to the pitot tube, including:

a plurality of pitot tube temperature sensors located inside the pitot tube configured to measure a pitot tube temperature; and

a system controller operably connected to the plurality of pitot tube temperature sensors, the system controller configured to:

select a minimum measured pitot tube temperature threshold based on the measured outside ambient air temperature

compare the measured pitot tube temperature to the selected minimum measured pitot tube temperature threshold for the measured outside ambient air temperature; and

determine the pitot tube has a blockage condition when the measured pitot tube temperature is below the minimum measured pitot tube temperature threshold.

9. The pitot tube system of claim 8 , further comprising a pitot tube heater to selectably heat the pitot tube;

wherein the system controller is configured to determine whether a pitot tube heater is operational; and

wherein the minimum measured pitot tube temperature threshold is selected based on the measured outside ambient air temperature and an operational status of the pitot tube heater.

10. The system of claim 8 , further comprising an alert system to provide an alert to a flight crew in the event the blockage condition is detected.

11. The system of claim 10 , wherein the alert is one or more of a visual alert or an aural alert.

12. The system of claim 8 , wherein the plurality of temperature sensors are three or more temperature sensors located at different longitudinal locations along the pitot tube.

13. The system of claim 8 , wherein the plurality of temperature sensors are located at different circumferential locations around the pitot tube.

14. The pitot tube system of claim 8 , further comprising one or more outside ambient air temperature sensors to obtain the outside ambient air temperature.

15. The pitot tube system of claim 8 , wherein the pitot tube includes one or more total pressure openings and one or more static pressure openings.

16. The pitot tube system of claim 8 , wherein the system operation is initiated by a user input at any point during operation of the pitot tube.