venerdì 23 settembre 2016

Avionics bending: CVR

1. General

A. The voice recorder system preserves a continuing record of the latest 30 or 120 minutes of flight crew communications and conversations. The four channel voice recorder receives inputs from the audio selector panels for the captain, the first officer, and the first observer, and from an area microphone in the flight compartment.

B. The voice recorder system consists of a recorder located in the aft passenger cabin ceiling and a control panel with an area microphone located on overhead panel P5.

C. 115 VAC power is supplied to the system from the right AC bus. The VOICE RECORDER circuit breaker, located on overhead panel P11, controls power to the system.

2. Component Details

A. Voice Recorder


The voice recorder is installed in the E7 equipment rack in the aft passenger cabin ceiling. The recorder is a thermally insulated, impact resistant, 4 MCU unit, and international orangein color.

The voice recorder contains a tape transport which includes the tape, tape drive, two four-track recording heads, two erase heads, two monitor heads, and a bulk erase coil. The unit also contains four recording amplifiers, a monitor amplifier, 65 kHz bias generator,
600 Hz test circuits and power supply.
(a) The recording tape is 308 feet long, 1/4 inch wide in a continuous endless loop. The four track tape runs at 1 7/8 IPS providing 30 minutes of recording time.
(b) The front panel contains a headphone jack and a underwater locator beacon (ULB). A headset inserted into the headphone jack will monitor all channels slightly delayed after they are recorded.
(3) An ULB is attached to the voice recorder front panel and is a self-contained device. The ULB will emit a 37.5-KHz signal when the water activated switch is closed. The ULB contains a dated label to indicate when the battery requires periodic replacement.

B. Voice Recorder Control Panel

The voice recorder control panel is located on overhead panel P5.
It contains an area microphone with preamplifier and filter circuits, a HEADPHONE jack to monitor system recording, a TEST switch to initiate the functional self test, a light or meter to
provide an indication of self test success or failure, and an
ERASE switch for data erasure.

Push the TEST switch will activate test circuits within the voice recorder. A tone is applied to all four channels. If the test is successful, the needle on the monitor meter moves and stays in the green area and you hear a tone in the headse

Push the ERASE switch will cause the voice recorder data to be completely erased. Bulk erasure is possible only when the airplane is on the ground with the parking brake set.




sabato 11 giugno 2016

Avionics bending: MCDP computer

The maintenance monitor system consists of a Maintenance Control Display Panel (MCDP) that monitors the status of the Flight Control Computers (FCC), Flight Management Computers (FMC), Thrust Management Computer (TMC), and their related sensors. The MCDP interrogates the computers after each landing, and stores up to five flight faults per computer in non-volatile memory for later interrogation by maintenance personnel.

A central processing unit in the MCDP controls and processes ground test commands, ground test functions, and on-ground and in-flight faults. The MCDP displays flight and ground faults, test number, name or status, and operator instructions. The MCDP controls and display panel are located on the front of the unit. The controls enable maintenance personnel to display faults and ground tests that include operator instructions. The MCDP is located in the main Electrical/Electronic (E/E) equipment center.

The remote control panel is mounted in the P61 panel and is used for displaying flight faults and for running ground tests from the flight deck. The MCDP remote display is through the EICAS system maintenance panel in the P61 panel. The MCDP display can be displayed on the EICAS with or without the remote control panel, by pressing the CONF/MCDP switch of the EICAS maintenance panel.
Maintenance Control Display Panel Interfacing Systems
(1) The primary MCDP interfaces are with each FCC, FMC, and TMC.Secondary interfaces with the MCDP consist of FCC, FMC, and TMC individual system sensors. Both primary and secondary interfaces are monitored by the MCDP during ground test functions.
(2) Primary Interfaces
(a) The left, center, and right flight control computers use ARINC 429 data buses for transmitting interface fault data to the MCDP and receiving ground test data from the MCDP. Analog discrete lines are used for ground test control.
(b) The left and right flight management computers use ARINC 429 data buses to transmit interface fault data to the MCDP. The MCDP can only interrogate the FMC for fault data. The MCDP ground tests do not affect the FMC systems.
(c) The thrust management computer uses an ARINC 429 data bus for transmitting interface fault data to the MCDP and receiving ground test data from the MCDP. An analog discrete line is used for ground test control of the TMC by the MCDP.
(3) Secondary Interfaces
(a) The mode control panel supplies control signals and receives status data from each FCC, FMC, and TMC on ARINC 429 data buses.
(b) Each FCC supplies analog control signals to its control servos and receives analog servo position signals. Each FCC receives sensor data on ARINC 429 data buses from the
associated Inertial Reference Unit (IRU) and air data computer.
(c) The TMC receives control signals on an ARINC 429 data bus from the thrust mode select panel. The TMC also transmits status data to the thrust mode select panel on an ARINC 429 data bus. The TMC supplies analog control signals to and receives analog
position signals from the autothrottle servomotor generator.




martedì 19 aprile 2016

Avionics bending: Tape Radio Altimeter

A. The radio altimeter (RA) system supplies vertical position data for use by the pilots for runway approach, landing, and takeoff. The RA system provides accurate measurement of absolute altitude (height
above terrain) from 2500 ft. to touchdown. Altitude data is routed to user systems on 429 digital data buses.

B. Three complete systems are installed. Each system consists of a
receiver/transmitter (R/T), and one transmit and one receive
antenna. Altitude data is displayed on the electronic attitude
director indicators (EADIs)and on tape radio altitude indicator if equipped.