The Air Data and Inertial Reference System (ADIRS) has three identical
Air Data and Inertial Reference Units (ADIRUs), one ADIRS Mode
Selector Unit (ADIRS MSU) and a number of sensors. The ADIRUs
receive information from the sensors to compute air and internal laser
gyros and the accelerometers to compute inertial data. This data is
displayed to the crew and sent to the MCDU and other A/C systems. The
sensors also send data to the Integrated Standby Instrument System (ISIS)
for standby display.
ADIRS SWITCHING (2)
GENERAL
The Air Data/Inertial Reference System (ADIRS) is composed of three
Air Data Inertial Reference Units (ADIRUs).
PRINCIPLE
Various instruments and systems receive data from the ADIRS for inertial
and air data display:
- the PFDs,
- the NDs,
- the ECAM SD,
- the Digital Distance and Radio Magnetic Indicator (DDRMI).
The ADIRUs transmit air data, attitude and navigation parameters to
various user systems. As an example, the ADIRS provides:
- barometric altitude data to the Air Traffic Control (ATC) system for
mode C and S,
- data to the Flight Augmentation Computers (FACs) for computation of
various characteristic speeds,
- data to the Weather Radar (WXR) system for antenna attitude
stabilization.
Basically, ADIRU 1 is associated with systems 1 and the DDRMI, ADIRU
2 with systems 2, and ADIRU 3 is in standby. ADIRU 3 can substitute
either system, for this purpose it has interfaces with the three Display
Management Computers (DMCs). If an Air Data Reference (ADR) or
an Inertial Reference (IR) fails, the AIR DATA or ATTitude HeaDinG
selectors enable the crew to use ADR 3 or IR 3. The manual switching
is mainly performed to recover displays. The computers select their inputs
according to the switching for consistency of computation and display.
NOTE: The ADIRU data sent to the ECAM SD are Static Air
Temperature (SAT), Total Air Temperature (TAT) and
International Standard Atmosphere (ISA)
ALIGNMENT OF THE IRS
The Flight Management Guidance and Envelope System (FMGES)
uses the reference point coordinates of the departure airport to align
the Inertial Reference System (IRS). It automatically finds these
coordinates in the database after the operator enters a company route
or an origin-destination city pair and pushes the ALIGN IRS key on
the MCDU. The operator can manually adjust these coordinates to
the gate position. The time necessary for a full alignment is 10 minutes.
It is necessary to do a specific alignment procedure between 73°and
82° north or south (refer to FCOM documentation). The alignment
procedure is not possible at more than 82° north or south.
“ON BAT” light is illuminated at ADIRS alignment initialization
for 5 sec.
Air Data and Inertial Reference Units (ADIRUs), one ADIRS Mode
Selector Unit (ADIRS MSU) and a number of sensors. The ADIRUs
receive information from the sensors to compute air and internal laser
gyros and the accelerometers to compute inertial data. This data is
displayed to the crew and sent to the MCDU and other A/C systems. The
sensors also send data to the Integrated Standby Instrument System (ISIS)
for standby display.
ADIRS SWITCHING (2)
GENERAL
The Air Data/Inertial Reference System (ADIRS) is composed of three
Air Data Inertial Reference Units (ADIRUs).
PRINCIPLE
Various instruments and systems receive data from the ADIRS for inertial
and air data display:
- the PFDs,
- the NDs,
- the ECAM SD,
- the Digital Distance and Radio Magnetic Indicator (DDRMI).
The ADIRUs transmit air data, attitude and navigation parameters to
various user systems. As an example, the ADIRS provides:
- barometric altitude data to the Air Traffic Control (ATC) system for
mode C and S,
- data to the Flight Augmentation Computers (FACs) for computation of
various characteristic speeds,
- data to the Weather Radar (WXR) system for antenna attitude
stabilization.
Basically, ADIRU 1 is associated with systems 1 and the DDRMI, ADIRU
2 with systems 2, and ADIRU 3 is in standby. ADIRU 3 can substitute
either system, for this purpose it has interfaces with the three Display
Management Computers (DMCs). If an Air Data Reference (ADR) or
an Inertial Reference (IR) fails, the AIR DATA or ATTitude HeaDinG
selectors enable the crew to use ADR 3 or IR 3. The manual switching
is mainly performed to recover displays. The computers select their inputs
according to the switching for consistency of computation and display.
NOTE: The ADIRU data sent to the ECAM SD are Static Air
Temperature (SAT), Total Air Temperature (TAT) and
International Standard Atmosphere (ISA)
ALIGNMENT OF THE IRS
The Flight Management Guidance and Envelope System (FMGES)
uses the reference point coordinates of the departure airport to align
the Inertial Reference System (IRS). It automatically finds these
coordinates in the database after the operator enters a company route
or an origin-destination city pair and pushes the ALIGN IRS key on
the MCDU. The operator can manually adjust these coordinates to
the gate position. The time necessary for a full alignment is 10 minutes.
It is necessary to do a specific alignment procedure between 73°and
82° north or south (refer to FCOM documentation). The alignment
procedure is not possible at more than 82° north or south.
“ON BAT” light is illuminated at ADIRS alignment initialization
for 5 sec.
