General
You can do a test of the ADF system from the MAT. These are the tests that are available from the operational test selection on the MAT:
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Left ADF System
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Right ADF System.
Operational Test
The operational test for the ADF system makes sure the ADF receiver operates normally.
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ADF SYSTEM -GROUND TEST
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GLOBAL POSITIONING SYSTEM -INTRODUCTION
General
The global positioning system (GPS) uses navigation satellites to supply accurate airplane position to airplane systems and to the flight crew.
Abbreviations and Acronyms
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ADIRU -air data inertial reference unit
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AIMS -airplane information management system
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BITE -built-in-test equipment
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CDU -control display unit
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CMCS -central maintenance computing system
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D/A -digital-to-analog
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FMCF -flight management computing function
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GP -general purpose
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GPS -global positioning system
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GPWC -ground proximity warning computer
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MAT -maintenance access terminal
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MMR -multi-mode receiver
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NCD -no computed data
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PPS -precision positioning service
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RAIM -receiver autonomous integrity monitor
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SPS -standard positioning service
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UTC -universal time (coordinated)
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GPS -GENERAL DESCRIPTION
General
The global positioning system (GPS) calculates:
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Latitude
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Longitude
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Altitude
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Accurate time
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Ground speed.
There are two GPS antennas. The MMRs send power to the antenna amplifier circuits. The left antenna receives satellite signals and sends them to the left multi-mode receiver (MMR). The right GPS antenna connects to the right MMR. The MMRs calculate the airplane position and accurate time. This data goes to the AIMS cabinets and the ground proximity warning computer (GPWC). The flight management computing function (FMCF) in the AIMS uses GPS data to calculate the airplane position.
The AIMS cabinets send GPS data to the air data inertial reference unit (ADIRU). The ADIRU uses GPS data to calibrate its internal sensors. This decreases inertial reference drift.
GPS time goes to the universal time coordinated function (UTCF) in AIMS. GPS time goes to the clocks in the flight deck through the AIMS cabinets. The clocks can show GPS time.
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GPS -GENERAL DESCRIPTION
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GPS -MAIN EQUIPMENT CENTER COMPONENT LOCATIONS
Equipment Center
The left MMR is on the E1-2 shelf. The center MMR is on the E1-3 shelf. The right MMR is on the E2-3 shelf.
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GPS -MAIN EQUIPMENT CENTER COMPONENT LOCATIONS
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GPS -ANTENNA LOCATIONS
General
The GPS antennas are on the top of the fuselage.
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GPS -ANTENNA LOCATIONS
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GPS -INTERFACES
Power and Antenna Interface
Each multi-mode receiver (MMR) has a circuit breaker. The 115v ac standby and transfer buses supply power to the MMRs.
Each MMR sends 12v dc to its GPS antenna. The power goes through the center conductor of the coaxial cable to each antenna. Amplifiers in the antennas use the power to increase the strength of the received RF signals from the satellites.
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