ADIRU Flashcards
Air Data
Information regarding the aircraft’s airspeed, altitude, and other atmospheric conditions.
Inertial Reference
Utilizes inertial sensors (gyroscopes and accelerometers) to determine the aircraft’s position, velocity, and attitude.
Attitude Reference
Provides information on the aircraft’s orientation in three-dimensional space (pitch, roll, and yaw).
Accelerometers
Instruments that measure the aircraft’s acceleration, used to calculate changes in velocity and position.
Gyroscopes
Devices that measure the aircraft’s angular rate of rotation, providing data for attitude determination and stabilization.
Pitot Tube
A device that measures the aircraft’s airspeed by sensing the difference between static and dynamic air pressure.
Total Air Temperature (TAT) Probe
Measures the temperature of the air entering the aircraft, used to correct airspeed readings for variations in air density.
Static Pressure Port
Openings on the aircraft’s surface that measure static air pressure, used in conjunction with the pitot tube to calculate airspeed and altitude.
Altitude Heading Reference System (AHRS)
Integrates data from the inertial sensors to provide accurate attitude and heading information.
Air Data Module (ADM)
Collects, processes, and formats air data information for use by other aircraft systems.
Kalman Filter
A mathematical algorithm used to estimate the aircraft’s state (position, velocity, and attitude) based on sensor measurements while minimizing errors.
Data Fusion
The process of combining information from multiple sensors to improve accuracy and reliability.
Redundancy
ADIRUs often feature redundant systems to ensure continued operation in the event of sensor failure or other malfunctions.
Self-Alignment
The ADIRU can automatically align itself with the Earth’s reference frame using internal algorithms and sensor data.
Inertial Navigation System (INS)
A subsystem of the ADIRU that utilizes inertial sensors to track the aircraft’s position and velocity relative to an initial starting point.
Air Data Computer (ADC)
Computes air data parameters such as airspeed, altitude, and mach number based on inputs from the air data sensors.
Health Monitoring
Continuous monitoring of ADIRU performance to detect faults or anomalies and initiate appropriate corrective actions.
Calibration
Regular calibration of sensors and system components to maintain accuracy and reliability over time.
Built-In Test Equipment (BITE)
Diagnostic features within the ADIRU that perform self-tests and diagnostic checks to ensure proper functioning.
Navigation Accuracy
The degree to which the ADIRU provides accurate position, velocity, and attitude information, crucial for safe and precise navigation.
Heading Reference
The aircraft’s directional orientation relative to a reference point, typically the Earth’s magnetic north or true north.
Rate Sensor
A type of sensor used in ADIRUs to measure the rate of change of specific parameters, such as angular rate (gyroscopes) or linear acceleration (accelerometers).
Navigation Mode
Different operating modes of the ADIRU, including inertial navigation, GPS-aided navigation, and air data computation.
Aircraft Dynamics
The study of how the aircraft’s motion and behavior are influenced by external forces such as aerodynamics, gravity, and control inputs.
Sensor Fusion
The process of integrating data from various sensors, such as accelerometers, gyroscopes, GPS receivers, and air data sensors, to improve overall system performance and reliability.
Attitude and Heading Reference System (AHRS)
A subsystem of the ADIRU that provides accurate attitude (pitch, roll, and yaw) and heading information using inertial sensors.
Mach Number
A dimensionless quantity representing the ratio of the aircraft’s speed to the speed of sound in the surrounding medium, crucial for high-speed flight operations.
Attitude Indicator
A display instrument that visually represents the aircraft’s attitude (pitch and roll) based on data provided by the ADIRU’s attitude sensors.
Flight Director
A system that provides guidance cues to the pilot based on inputs from the ADIRU, assisting in the execution of flight maneuvers and procedures.
Navigation Accuracy
The degree of precision with which the ADIRU calculates the aircraft’s position, velocity, and attitude, influenced by sensor accuracy and error correction algorithms.
Flight Envelope Protection
Automated systems within the ADIRU that prevent the aircraft from exceeding safe operating limits, such as maximum bank angle or stall speed.
Inertial Reference Frame
A coordinate system fixed to the aircraft’s structure, used as a reference for inertial navigation calculations performed by the ADIRU.
Airspeed Indicator
A display instrument that indicates the aircraft’s airspeed based on data from the ADIRU’s air data sensors, including the pitot-static system.
Navigation Solution
The calculated position, velocity, and attitude of the aircraft provided by the ADIRU, used for flight planning, navigation, and control.
Data Integration
The process of combining information from multiple sensors and sources within the ADIRU to generate accurate and reliable flight data.
Flight Control System
The system that translates inputs from the ADIRU into control surface movements to maneuver the aircraft safely and efficiently.
Inertial Measurement Unit (IMU)
A subsystem of the ADIRU that consists of accelerometers and gyroscopes used to measure linear and angular accelerations.
Kalman Filtering
A mathematical technique used in the ADIRU to combine noisy sensor measurements with a dynamic model to estimate the true state of the aircraft.
Drift Correction
A process in which the ADIRU compensates for gyroscopic drift and sensor biases over time to maintain accuracy in attitude determination.
Accelerometer Bias
The constant offset in accelerometer measurements due to imperfections in sensor calibration or environmental factors, corrected by the ADIRU.
Gyroscope Bias
The constant angular offset in gyroscope measurements caused by sensor imperfections or external disturbances, compensated for by the ADIRU.
Inertial Navigation Error
The accumulation of errors in position, velocity, and attitude estimates over time due to inaccuracies in sensor measurements and model assumptions.
Navigation Performance Monitoring
Continuous evaluation of the ADIRU’s navigation solution to assess its accuracy and reliability relative to predefined performance criteria.
Navigation Uncertainty
The degree of confidence or error bounds associated with the ADIRU’s navigation solution, influenced by sensor accuracy, environmental conditions, and algorithmic limitations.
Dead Reckoning
A navigation technique employed by the ADIRU that estimates the aircraft’s position based on its known starting point, heading, airspeed, and elapsed time, without external reference.
Attitude Reference System (ARS)
The subsystem of the ADIRU responsible for providing accurate attitude information to the aircraft’s flight control system and avionics displays.
Sensor Fusion
The process by which the ADIRU combines data from multiple sensors, such as accelerometers, gyroscopes, and air data sensors, to enhance navigation accuracy and reliability.
Navigation Integrity
The assurance provided by the ADIRU that the navigation solution meets predefined accuracy and reliability requirements, essential for safe and efficient flight operations.
Heading Reference System (HRS)
The component of the ADIRU that generates precise heading information for navigation purposes, often incorporating magnetic heading correction algorithms.
Sensor Calibration
The process of adjusting sensor outputs to minimize errors and discrepancies in measurement, typically performed periodically or following maintenance procedures.
Navigation Initialization
The procedure by which the ADIRU initializes its navigation solution using known position, attitude, and velocity information before the start of a flight or after a system reset.
Flight Mode Annunciator (FMA)
A display interface that communicates the current operating mode and status of the ADIRU’s navigation and flight control systems to the flight crew.
Attitude Stabilization
The process of maintaining the aircraft’s desired orientation and stability using control inputs derived from the ADIRU’s attitude reference information.
Navigation Update Rate
The frequency at which the ADIRU calculates and updates its navigation solution, typically measured in Hertz (Hz) or updates per second.
Navigation Data Integrity
The reliability and trustworthiness of the navigation data provided by the ADIRU, essential for safe and precise navigation during all phases of flight.
System Redundancy Management
The ADIRU’s ability to maintain operational continuity and reliability in the presence of sensor failures, system faults, or unexpected disruptions, often through redundant sensor configurations and fault-tolerant algorithms.
Sensor Failures
Individual sensors within the ADIRU, such as accelerometers, gyroscopes, pitot tubes, or static ports, may malfunction due to wear and tear, contamination, or electronic faults.
Software Issues
Software bugs or glitches in the ADIRU’s firmware or software algorithms can lead to incorrect data processing, navigation errors, or system instability.
Calibration Errors
Incorrect sensor calibration or calibration drift over time can result in inaccurate measurements and degraded performance of the ADIRU.
Environmental Factors
Extreme temperatures, humidity, or exposure to moisture can affect the performance of ADIRU components, leading to sensor drift, corrosion, or electrical failures.
Electrical Faults
Wiring faults, connector failures, or power supply issues can disrupt communication between ADIRU components or cause intermittent failures in sensor readings.
Vibration and Shock
High levels of vibration or mechanical shock during aircraft operation can damage sensitive components within the ADIRU, leading to premature failure or degraded performance.
Component Aging
As ADIRU components age, they may experience degradation in performance, increased susceptibility to failure, or reduced reliability, especially if proper maintenance and replacement schedules are not followed.
External Interference
Electromagnetic interference (EMI) from nearby electronic devices or radio frequency (RF) signals can disrupt the operation of ADIRU sensors or introduce errors into sensor readings.
Integration Issues
Compatibility issues or communication errors between the ADIRU and other avionics systems onboard the aircraft can lead to data synchronization problems or system malfunctions.
Human Error
Improper installation, maintenance procedures, or operational errors by maintenance personnel or flight crew can contribute to ADIRU failures or inaccuracies in navigation data.
Environmental Contamination
Foreign object debris (FOD), dust, debris, or insects entering the ADIRU housing or sensor openings can obstruct sensor operation, leading to performance degradation or failure.
Power Supply Interruptions
Loss of electrical power or voltage fluctuations can disrupt the operation of the ADIRU, causing temporary or permanent system failures until power is restored.
Inertial Navigation Drift
Over time, the inertial sensors within the ADIRU may experience drift, leading to gradual deviations in position, velocity, or attitude estimates if not corrected through periodic calibration or realignment procedures.
Redundancy Management Failures
Errors in the ADIRU’s redundancy management system or failure detection algorithms may result in inadequate fault detection, isolation, or recovery mechanisms, compromising system reliability and safety.
