Method of verifying the consistency of values given by an incidence probe of an aircraft

Patent metadata

Field	Value
Publication number	US-9304499-B2
Application number	US-201313848273-A
Country	US
Kind code	B2
Filing date	Mar 21, 2013
Priority date	Mar 21, 2012
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

The invention pertains to a method and apparatus for verifying the consistency of the values given by an angle of attack probe of an aircraft. The method and apparatus verifies the proper operation of the angle of attack probe by using the aircraft's vertical load factor measurement provided by an accelerometer to estimate the angle of attack and then comparing the estimated angle of attach with the measure angle of attack.

First claim

The invention claimed is:

1. A method for verifying the consistency of an angle of attack probe mounted on an aircraft, where said angle of attack probe provides a first signal, the method comprising:
measuring variations in amplitude of a second signal comprising a vertical load factor measurement signal, said second signal provided by at least one accelerometer mounted aboard the aircraft; and
comparing with a first threshold the measured variations in amplitude of said second signal, and, if said measured variations in amplitude exceeds said first threshold, then performing the following steps during a time window of limited duration:
measuring variations in amplitude of said first signal during said time window; and
comparing with a second threshold the measured variations in amplitude of said first signal, wherein said first signal is identified as inconsistent if the measured variations in amplitude of the first signal do not exceed the second threshold during said duration of said time window.

2. A method for verifying the consistency of the measurement of an angle of attack probe mounted on an aircraft, the angle of attack probe providing an angle of attack measurement signal (S α ), termed a first signal, the method comprising successively:
E1) analysis and measurement of variations in amplitude of a vertical load factor measurement signal (S NZ ), termed a second signal, provided by at least one accelerometer mounted aboard the aircraft;
E2) comparison of the variations in amplitude of the second signal with a first threshold (ε 1 ), an exceeding of the first threshold by a variation in amplitude of the second signal triggering the following successive steps for a time window of limited duration (T):
E3) calculation of variations in amplitude of the first signal; and
E4) comparison of the variations in amplitude of the first signal thus calculated with a second threshold (ε 2 );
the measurements of variations in amplitude provided by the angle of attack probe being identified as inconsistent if the variations in amplitude of the first signal do not exceed the second threshold during the duration (T) of the time window.

3. The method according to claim 2 , wherein the value of the second threshold (ε 2 ) is obtained as the product of the variation in amplitude (A Nz ) of the second signal and of a coefficient of proportionality (K min ) between the variation of the angle of attack (α) and the variation of the vertical load factor (N z ) of the aircraft, the coefficient of proportionality being given by the following equation:

K
min

=

m
.
g
.

q
_

.
S
.

Max
⁡

(

∂

C
z

∂
α

)

with q =0.7·p s ·M 2 is the kinetic pressure
and where m represents the mass of the aircraft, g is the gravity constant, q is the kinetic pressure, M is the Mach number, p s is the static pressure, S is the reference area of the aerofoil, C z the lift coefficient of the aircraft, and

Max
⁢

⁢

(

∂

C
z

∂
a

)

is the maximum value of the term

(

∂

C
z

∂
a

)

.

4. The method according to claim 2 , wherein the value of the first threshold (ε 1 ) varies according to the flight direction (Pc) of the aircraft and corresponds to the value of the load factor measurement signal (S NZ ) amplitude obtained for a detectable minimum variation of the angle of attack (α) upon the relevant flight point (Pc) of the aircraft.

5. The method according to claim 2 , wherein the value of the first threshold (ε 1 ) is fixed and corresponds to the value of the load factor measurement signal (S NZ ) amplitude obtained for a detectable minimum variation of the angle of attack (α) for a particular flight point (Pc) of the aircraft.

6. An apparatus for verifying the consistency of the measurements of an angle of attack probe mounted on an aircraft, where said probe provides angle of attack measurements in the form of a first signal, said apparatus comprising:
a microcontroller,
a first sub-system, and
a second sub-system,
said first subsystem including an accelerometer mounted in said aircraft and configured to measure variations in a vertical load factor of said aircraft and provide a second signal comprised of a boolean signal to said microcontroller indicative of the variations exceeding a first threshold, the microcontroller, in response to said variations exceeding said first threshold, configured to activate the second sub-system for a time window of predetermined duration starting from an instant at which the variations exceed said first threshold; and
said second subsystem, responsive to said first signal, configured to provide the microcontroller with a boolean signal indicative variations in amplitude of the first signal exceeding a second threshold, said second threshold provided by the microcontroller, the probe being identified as inconsistent if the variations in amplitude of the first signal do not exceed the second threshold for the duration of the time window,
wherein the microcontroller is configured to provide a boolean output signal indicative of the exceeding of the second threshold by the variations in amplitude of the first signal.

7. An apparatus for verifying the consistency of the measurements of an angle of attack probe mounted on an aircraft, the probe providing an angle of attack measurement signal (S α ), termed a first signal, the apparatus comprising:
a first (S 1 ) sub-system controlled by the microcontroller (μc), and
a second (S 2 ) sub-system controlled by the microcontroller (μc),
the first sub-system (S 1 ) receiving as input a vertical load factor measurement signal (S NZ ), termed a second signal, provided by at least one accelerometer mounted aboard the aircraft and providing the microcontroller with a boolean signal (B 1 ) indicative of the exceeding of a first threshold (ε 1 ) by a variation in vertical

Assignees

• Airbus Operations Sas

Inventors

• Schott Gregory
• Joalland Benoit
• Bourissou Céline
• Le Tron Xavier
• Ronceray Didier

Classifications

• G01P13/025 Primary

  indicating air data, i.e. flight variables of an aircraft, e.g. angle of attack, side slip, shear, yaw · CPC title

• G01P21/00

  Testing or calibrating of apparatus or devices covered by the preceding groups · CPC title

• G01P15/00

  Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration · CPC title

• G05B1/01 Primary

  electric · CPC title