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TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM - раздел Программирование, Traffic Alert And Collision Avoidance Syst...
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TRAFFIC ALERT AND COLLISION AVOIDANCE SYSTEM
TCAS - GENERAL DESCRIPTION
TCAS - COMPONENT LOCATION
Electronic Equipment Compartment
The TCAS computer is in the electronic equipment
compartment.
TCAS - ANTENNA LOCATION
General
The top TCAS directional antenna is at station 385 on top of the fuselage. The bottom TCAS directional antenna is at station 305 on the bottom of the fuselage.
TCAS - POWER, ANTENNAS, ANALOG, DISCRETE INTERFACES AND PROGRAM PINS
Power
The TCAS computer gets 115v ac from AC transfer bus-1 through the TCAS circuit breaker on the P18 circuit breaker panel.
Antennas
There are two TCAS directional antennas. The TCAS directional antennas receive traffic airplane reply signals. They also transmit the TCAS interrogation signals.
Landing Gear Lever Switch
The discrete from the landing gear lever switch tells the TCAS computer that the landing gear is down. When the TCAS computer gets this discrete, the TCAS computer makes the bottom directional antenna become an omnidirectional antenna.
PSEU
The discrete from the PSEU supplies in-air or on-ground status to the TCAS computer. The air/ground discrete inhibits TCAS operation on the ground and inhibits tests when in the air. The air/ground discrete also controls flight leg increments in the TCAS nonvolatile memory.
GPWC - Advisory Inhibit Discretes
The GPWC sends one discrete to the TCAS computer. This discrete inhibits TCAS aural and visual warnings when the GPWC makes any voice message.
GPWC - Advisory Inhibit Discretes
The GPWC sends three discretes to the TCAS computer. These discretes inhibit TCAS aural and visual warnings during all GPWS modes except mode 6 (altitude callouts).
Weather Radar
The TCAS computer gets one discrete from the weather radar. This discrete inhibits all TCAS aural warnings and changes RAs to TAs when the weather radar makes a predictive windshear warning.
Suppression Input/Output
The TCAS computer gets a suppression pulse when an ATC transponder or DME interrogator transmits. When the TCAS computer transmits, it sends a suppression pulse to the ATC transponders and the DME interrogators.
DEU - Display Status
A discrete from either DEU goes to the TCAS computer when the DEU loses the ability to show TCAS displays. When the TCAS computer gets this discrete, the TCAS computer does not do these functions:
· Send TCAS display outputs to the DEU
· Send TCAS aurals to the REU
· Transmit coordination data to traffic airplanes with TCAS.
REU - TCAS Aurals - Voice Outputs
The TCAS computer sends resolution advisory (RA) and traffic advisory (TA) aural signals to the remote electronic unit (REU). The REU amplifies the RA and TA aurals. Then it sends them to the flight interphone speakers and headsets to alert the flight crew.
TCAS - DIGITAL INTERFACES
General
The TCAS computer has digital interfaces with these
components:
· ATC 1 transponder
· ATC 2 transponder
· Radio altimeter 1 transceiver
· Radio altimeter 2 transceiver
· Left air data inertial reference unit (ADIRU)
· Display electronic unit 2 (DEU 2)
· Display electronic unit 1 (DEU 1)
· Flight data acquisition unit (FDAU).
TCAS Inputs from ADIRU
The left ADIRU supplies these inputs to the TCAS computer:
· Airplane roll attitude
· Airplane pitch attitude
· Airplane heading.
NOTE: Airplane heading is the only ADIRU input used by the TCAS computer.
NOTE: These inputs are not used by the TCAS computer at this time.
TCAS Outputs to DEUs
The TCAS computer supplies resolution advisory (RA) and traffic advisory (TA) data to the DEUs. This includes all traffic data for TCAS displays.
TCAS Outputs to the FDAU
The FDAU receives the same TCAS data that goes to the DEUs.
TCAS - DIGITAL INTERFACES
Purpose
The TCAS computer is the main component of the TCAS. It controls these functions:
· Surveillance
· Tracking
· Advisory
· Air-to-air maneuver coordination.
The TCAS computer sends signals which tell the flight crew to make one of these maneuvers:
· Keep the current flight plan
· Make flight maneuvers to prevent a possible collision with other airplanes in the area.
Physical Description
The TCAS computer is a 6 MCU size unit. It weighs 28 lbs (11.3 kg).
Functional Description
The TCAS computer transmits 1030 MHz pulse-coded interrogation signals. It receives 1090 MHz pulse-coded reply signals from intruder airplanes with an ATC transponder.
Front Panel Self-Test
You push the test switch on the front panel to start a test of the TCAS. The LED indications come on to show system status.
Performance Management Recording
The TCAS computer has a slot for a Personal Computer
Memory Card International (PCMCIA) card. The recorder
function provides the capability to store information about
TCAS events for post-flight analysis. These are the RECORD light emitting diodes (LEDs):
· An ACTIVE to show card recording
· A FULL to show card recording complete.
Front Panel Connectors
There is one connector on the front panel. You use it to load revised software and for automated test equipment.
TCAS - ATC/TCAS CONTROL PANEL
General
The ATC/TCAS control panel controls the TCAS computer.
Function Select Switch
You use the function select switch to select one of these TCAS modes:
· TA/RA mode. The displays show all targets. This is the
normal mode of operation for TCAS.
DIRECTIONAL ANTENNA
CAUTION: DO NOT PAINT THE RADIATION SURFACE OR THE
BACKPLATE OF THE ANTENNA. PAINT DOES NOT
PERMIT THE ANTENNA TO RADIATE OR RECEIVE
RF SIGNALS.
CAUTION: TO PREVENT DAMAGE TO THE ANTENNA CABLES, DO NOT PULL ON THEM.
TCAS - FUNCTIONAL DESCRIPTION
I/O
The I/O circuit gets this on-board airplane systems data:
· Magnetic heading data from the left ADIRU
· Coordination and control data from the ATC transponder system
· Barometric altitude from the left or right ADIRU from the
active ATC
· Radio altitude from the radio altimeters
· Resolution advisory status from the DEUs
· Landing gear down discrete from the landing gear lever
switch
· Aural inhibit discrete interface with the GPWC
· Aural inhibit discrete interface with the weather radar
· Air/ground data from the PSEU.
Program pins set these parameters in the TCAS computer:
· Altitude limits
· Aural warning volume levels
· Self test inhibits
· Standby on ground
· Intruders on ground disabled.
The I/O circuits send this data to the CPU.
CPU
The CPU gets the data from the inputs of the I/O and puts it into
memory. The CPU combines the input data and the data it
receives from the signal processor. The CPU makes the
necessary calculations for the TCAS displays and aural
messages.
The CPU sends TCAS display data to the CDS DEUs. It shows on these indicators:
· Attitude indicators (AI)
· Navigation display (ND)
The CPU sends the display data to the flight data acquisition unit (FDAU).
It also sends signals through the speech processor circuits to the REU to make TCAS aurals.
Suppression
The suppression circuit sends a suppression pulse when the TCAS computer transmits. The TCAS computer receives a suppression pulse when an onboard ATC transponder or DME interrogator system transmits. This suppression pulse stops the TCAS computer receiver and transmitter circuits.
Speech Processor
When there is a TA, RA, or during a self-test, the TCAS computer sends signals to the speech processor. The speech processor sends the aural alerts to the REU. The REU sends them to the flight compartment.
During aural annunciations the GPWC sends an analog discrete to the TCAS computer to prevent TCAS advisories.
During predictive windshear annunciations the weather radar sends an analog discrete to the TCAS computer to prevent TCAS advisories.
Receiver Processor
The receiver gets the target replies from the antennas. The receiver uses the phase of the received signals to determine the bearing of the target. The receiver sends the signal to the signal processor to calculate the range to the target. The receiver decodes the target altitude from the reply signal. The receiver also receives and decodes coordination replies from targets equipped with TCAS.
Transmitter
The transmitter has a 1030 MHz output. The transmitter gets signals from the signal processor. The transmitter sends the formatted signals to the beam steering and attenuator (ATT) circuits. The transmitter controls the beam steering circuits and whisper/shout attenuator.
BITE
The TCAS computer has BITE. The BITE continuously monitors TCAS for system faults and interface faults during normal operation. Also, when you start a self-test, the BITE makes test signals and sends them to the signal processor and receiver/ transmitter circuits. The BITE monitors for system faults and interface faults during the self-test.
When the BITE detects a fault through the continuous fault monitor, the fault goes into the fault memory. It also goes to the I/O circuits for output to the CDS DEUs and the FDAU.
When the BITE detects a fault during a self-test, the fault data goes to the I/O and then to these systems:
· DEUs
· REU* FDAU
· TCAS computer status LEDs if test is done from computer front panel.
Directional Antenna
The directional antenna has four elements spaced 90 degrees apart. Each element is independent of the others and has it own coaxial connector.
TCAS - BASIC OPERATION
Mode S Interrogation
Mode S transponders transmit a squitter signal once each second. The signals contain a 24-bit airplane address. The TCAS listens for mode S squitter signal transmissions from airplanes that have mode S transponders. When the TCAS receives an address, it puts that airplane on a roll call list. The TCAS then interrogates the mode S transponder of the traffic airplane with the discrete 24-bit airplane address on the roll call list.
Air-to-Air Coordination
If the target also has TCAS, the two TCAS computers communicate with each other using the mode S transponders. Both TCAS computers calculate an escape path if it is necessary. Both TCAS computers send the escape path to the mode S transponder in the other airplane. This sets up the airto-air mode S data link between the airplanes.
TCAS - SURVEILLANCE AREA
General
The TCAS tracks and evaluates up to 30 airplanes that are in the surveillance area. Airplanes in the surveillance area are put into one of these four groups:
· Resolution advisory (RA) group
· Traffic advisory (TA) group
· Proximate traffic
· Other traffic.
TCAS has a maximum surveillance area that is 8700 feet above and below your airplane. It has a range of 40 nm.
Proximate Traffic and Other Traffic
Proximate traffic is an airplane with a relative altitude
separation less than 1200 feet, is in a 6 nm radius of your
airplane, and is not a TA or RA threat.
Other traffic is an airplane with a range more than 6 nm that is not a TA or RA threat. If the range is less than 6 nm, the relative altitude must be more than 1200 feet.
TCAS - CONTROL AND DISPLAY
General
The EFIS control panel and the ATC control panel control the TCAS data that shows on the displays.
TCAS - NAVIGATION DISPLAY
Range Data
Push the TFC switch on the EFIS control panel to show TCAS data. The range the EFIS control panel selects also shows on the ND.
Altitude Readout
Relative altitude shows in the same color as the traffic symbol on the NDs.
Absolute Altitude
The target sends barometric altitude to the TCAS computer. This altitude shows in thousands and hundreds of feet. If the traffic is above, the digits show above the traffic symbol. If the traffic is below, the digits show below the traffic.
If the altitude cannot be calculated, the altitude display does not show.
Vertical Motion Arrow
A vertical motion arrow shows on the right side of the traffic symbol. It is the same color as the traffic symbol.
The arrow points down if the traffic airplane goes down at a rate more than or equal to 500 fpm. The arrow points up if the traffic airplane is in a climb at a rate more than or equal to 500 fpm. The arrow does not show for rates less than 500 fpm.
TRAFFIC
The red TRAFFIC message shows any time there is an RA. The amber TRAFFIC message shows any time there is a TA and no RA. The TRAFFIC message shows in all ND formats with the TFC switch on the EFIS control panel set to ON or OFF.
TCAS - ATTITUDE INDICATOR DISPLAY
General
These are the two types of TCAS vertical resolution advisories that can show on the attitude indicator (AI):
· TCAS RA - down advisory
· TCAS RA - up advisory.
These symbols only show for an RA when:
· The function selector on the ATC control panel is in the TA/
RA position
· The TCAS communicates with threat airplanes that give their altitude. Description
The red advisories show on the attitude display. They tell the flight crew to avoid some pitch movements.
The flight crew uses the advisories to avoid a possible collision with threat airplanes.
TCAS - AURAL MESSAGES
General
Aural advisory messages occur during these conditions:
· Traffic advisories (TA)
· Resolution advisories (RA)
· TCAS system tests.
Traffic Advisory Aural
When a traffic advisory occurs, the aural message TRAFFIC TRAFFIC comes on. This message tells the flight crew to monitor the display for intruder traffic.
Resolution Advisory
These are the two types of aural messages that can come on during a resolution advisory (RA):
· Preventive action RA
· Corrective action RA.
Preventive Action RA
This type of RA occurs when at the closest point of approach (CPA) the present vertical speed results in a safe altitude separation from the threat airplane. When this happens, the aural advisory is MONITOR VERTICAL SPEED - MONITOR VERTICAL SPEED. This message tells the flight crew to do these things:
· Maintain the flight path
Self-Test Aural
At the completion of the self-test, the TCAS computer sends the status aural to the flight compartment. TCAS SYSTEM FAIL indicates that the TCAS computer has a failure. TCAS SYSTEM TEST FAIL indicates an input to the TCAS system has a failure.
TCAS - SELF-TEST INDICATIONS ON DISPLAYS
General
You can start a self-test from the ATC/TCAS control panel or from the TCAS computer front panel test switch.
During a test, TCAS test signals go to these:
· NDs
· ADIs
· Front panel of the TCAS computer.
At the end of the test, a TCAS test aural goes to the flight
interphone speakers.
TCAS Self-Test Indications – AI
If the test passes, the AI shows the red RA up and down
advisory cues.
If the test fails, the AI does not show any RA advisories.
TCAS - SELF-TEST INDICATIONS ON TCAS COMPUTER FRONT PANEL
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