*
Inertial altitude
*
Wander heading
*
Vertical speed.
Barometric Altitude Input
The SAARU uses barometric altitude from its air data section to calculate vertical speed. This barometric altitude prevents fast changes in vertical speed.
ARINC 629 Output
The SAARU sends inertial data on the center flight controls ARINC 629 bus. The SAARU data goes to the:
*
Left and right AIMS cabinets
*
Left, right, and center primary flight computers (PFCs)
*
Left, right, and center autopilot flight director computers.
ARINC 429 Output
The SAARU sends attitude data through the output buffer to the standby attitude indicator.
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General
Redundancy management logic in the SAARU selects or votes a value for the inputs that come from the redundant air data sensors.
Total Air Temperature
The total air temperature (TAT) redundancy management logic calculates an average of the TAT values from TAT inputs 1 and
2.
Pitot Heater Valid
Pitot heater valid signals come from the left, center, and right pitot air data modules (ADMs). The pitot heater valid signals go to the pitot ADM redundancy management logic.
Pitot Pressure
Pitot pressure comes from the left, center, and right pitot air data modules (ADMs). The pitot ADM redundancy management logic calculates an average of the pitot pressures from the ADMs.
AOA Heater Valid
The angle of attack (AOA) heater valid signals go to the AOA redundancy management logic. The AOA redundancy management logic uses the AOA heater valid signal to find out if the AOA sensors are valid.
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AOA Input
The AOA values go to the function that calculates the corrected AOA.
Speedbrake Lever Past Arm Signal
The primary flight computers (PFCs) supply the air ground speedbrake lever past arm signals to the SAARU. Input data redundancy management logic selects one of the PFC signals. The speedbrake lever past arm signals go to the AOA redundancy management logic.
Air/Ground, Nose Gear Position, and Flap Position
The proximity sensor electronics units (PSEUs) supply the air/ ground and the nose gear position signals to the AIMS cabinets.
The flap/slat electronics units (FSEUs) supply the flap position signals to the AIMS cabinets.
The AIMS cabinets supply the signals to the SAARU. An input data redundancy management logic selects one of the PSEU signals, and one of the FSEU signals.
The air/ground signal, nose gear position, and flap position signals go to the calculate corrected AOA function.
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Calculate Corrected AOA
The calculate corrected AOA logic calculates the left and right corrected AOA. The calculate corrected AOA function receives these additional signals:
*
Mach
*
Pitch rate
*
True airspeed
*
Flap position
*
Nose gear position.
The corrected AOAs go to the AOA redundancy management logic.
AOA Redundancy Management
The AOA redundancy management logic uses a modified average calculation. The modified average calculation calculates an average of three AOA values, the left corrected AOA, the right corrected AOA, and a calculated AOA. The calculated AOA logic receives inputs from the inertial and air data systems to calculate the calculated AOA.
Static Pressure
Static pressure comes from the left, center, and right static air data modules (ADMs). The static source error correction (SSEC) uses Mach and corrected AOA to compensate for errors in measurement of static pressure. The static pressure goes to the static ADM redundancy management logic.
The static ADM redundancy management logic calculates an average of the static pressures from the ADMs. The static ADM redundancy management logic uses body accelerations from the SAARU inertial reference section to determine error thresholds.
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