System and method for detecting blocked pitot-static ports

1. A method of monitoring an avionics system for pneumatic blockages, the method comprising:

providing a first sensor in association with an air inlet for detecting air pressure,

providing a second sensor in association with the air inlet for detecting air pressure, the second sensor having a frequency content higher than the frequency content of the first sensor;

calculating, using a computer coupled to the first and second sensors, aircraft movement data using the detected air pressure from the first sensor; and

determining, independently from the calculated aircraft movement data, if the first sensor is faulty or if the air inlet is blocked in dependence upon the frequency content in output from the second sensor; and

using the detected air pressure from the second sensor to determine the aircraft movement data when it is determined the first sensor is faulty.

2. A method of monitoring an avionics system as recited in claim 1 wherein the first sensor includes a filter operable to provide a signal from the first sensor having a frequency content suitable for determining aircraft movement data.

3. A method of monitoring an avionics system as recited in claim 1 wherein the air inlet includes a pitot tube.

4. A method of monitoring an avionics system as recited in claim 1 wherein the air inlet includes a static port.

5. A method of monitoring an avionics system as recited in claim 1 , wherein the aircraft movement measurement includes airspeed.

6. A method of monitoring an avionics system as recited in claim 1 , wherein the aircraft movement measurement is selected from the group consisting of aircraft altitude, angle of attack and angle of sideslip.

7. A method of monitoring an avionics system as recited in claim 1 further including the step of using the detected air pressure from the second sensor to determine a second aircraft movement measurement.

8. A method of monitoring an avionics system as recited in claim 1 wherein the higher frequency content of the second sensor provides a measurement for input to gust load alleviation systems.

9. An avionics system comprising:

an air pressure measurement system including;

a first sensor positioned in association with an air inlet for detecting air pressure, the first sensor having a first frequency response;

a second sensor positioned in association with the air inlet for detecting air pressure, the second sensor having a frequency response higher than the frequency response of the first sensor; and

an air data computer coupled to each first and second sensor operative to calculate a first aircraft movement measurement using the detected air pressure from the first sensor and further operative to determine if the first sensor is faulty or if the air inlet is blocked in dependence upon the frequency content and amplitude of the output from the second sensor,

wherein the air data computer is further operative to use the detected air pressure from the second sensor to determine the first aircraft movement measurement when it is determined the first sensor is faulty.

10. An avionics system as recited in claim 9 wherein the air measurement system further includes a pitot tube providing the air inlet.

11. An avionics system as recited in claim 9 wherein the air measurement system further includes a static port providing the air inlet.

12. An avionics system as recited in claim 9 wherein the aircraft movement measurement includes airspeed.

13. An avionics system as recited in claim 9 wherein the aircraft movement measurement data includes aircraft altitude.

14. An avionics system as recited in claim 9 wherein the air data computer is further operative to use the detected air pressure from the second sensor to determine a second aircraft data measurement.

15. An avionics system as recited in claim 9 wherein the higher frequency response of the second sensor provides a measurement for input to gust load alleviation systems.

16. A method of monitoring an avionics system as recited in claim 1 ,

wherein the first sensor is positioned in an aircraft and in air flow communication with an air inlet with at least a portion of the air inlet positioned on an external portion of the aircraft for detecting air pressure external of the aircraft, the first sensor having a first frequency response;

wherein the second sensor is positioned in an aircraft and in air flow communication with the air inlet for detecting air pressure external of the aircraft, the second sensor having a frequency response higher than the frequency response of the first sensor;

wherein calculating aircraft movement data further comprising calculating a measurement determination for the aircraft using the computer with the detected air pressure from the first sensor; and

wherein determining if the first sensor is faulty or if the air inlet is blocked further comprising determining in the computer if the first sensor is faulty or if the air inlet is blocked in dependence upon the frequency content and amplitude of the output from the second sensor.

17. An avionics system comprising:

an air pressure measurement system including;

an air probe member;

a sensor operatively coupled to the air probe member providing a first electrical signal indicative of an air pressure measurement from the air probe member and a second electrical signal indicative of an air pressure measurement from the air probe member having a frequency response higher than the frequency response of the first electrical signal; and

an air data computer coupled to each first and second electrical signals operative to calculate an aircraft movement measurement using the first electrical signal and further operative to determine if the air probe member is blocked in dependence upon the frequency content and amplitude of the second electrical signal,

wherein the air data computer uses the second electrical signal to calculate a second aircraft movement measurement.