Functional Description. Voice recorder system

VOICE RECORDER SYSTEM

General

The voice recorder continuously records these:

· Flight crew communications

· Flight compartment sounds.

The voice recorder keeps the last 120 minutes of audio.

Abbreviations and Acronyms

· ACP - audio control panel

· A/D - analog-to-digital

· ARINC - aeronautical radio incorporated

· BITE - built in test equipment

· capt - captain

· CSMU - crash survivable memory unit

· D/A - digital-to-analog

· F/O - first officer

· F/OBS - first observer

· Hz - hertz

· mic - microphone

· REU - remote electronics unit

· ULB - underwater locator beacon

· V AC - volts alternating current

· V DC - volts direct current

· VR - voice recorder

· xfr – transfer

General

The voice recorder unit makes a record of flight crew communication and flight compartment sounds. It erases the communication data automatically so that the memory stores only recent audio.

The voice recorder unit keeps the last 120 minutes of communication data in memory.

The voice recorder unit receives audio from the remote electronics unit (REU) and the area microphone. The area microphone is in the cockpit voice recorder panel.

The voice recorder unit receives time from the clock system for reference.

Components

The voice recorder system has these components:

· Cockpit voice recorder panel

· Voice recorder switch

· Voice recorder unit.

Functional Description

The pilot uses the voice recorder switch to control voice recorder power. The AUTO switch position provides automatic control. In this position, the voice recorder receives power through the time delay relay. When an engine is at or above idle(бездействующий, холостой), an engine running relay energizes the time delay relay.

The energized relay keeps voice recorder power on from engine start to engine shutdown. The time delay relay also keeps power for an additional five minutes after engine shutdown to let the pilots complete postflight checks.

The ON position lets you apply power to the voice recorder for maintenance or for preflight tests. In this position, the voice recorder switch latches while it supplies the power. It gives this power until an engine starts or until you put the switch back to AUTO. The switch automatically goes to AUTO when an engine is at or above idle.

The voice recorder unit collects these audio at the same time:

· Captain microphone and headphone

· First officer (F/O) microphone and headphone

· First observer (F/OBS) microphone and headphone

· Area microphone on the cockpit voice recorder panel.

The voice recorder unit also receives time from the clock system.

The inputs from the captain, first officer, and first observer microphones go to the REU. The REU mixes each station microphone audio with that station headphone audio. The REU then increases the audio signal and sends it to the voice recorder.

The area microphone collects flight compartment sounds, such as voices and aural warnings. The cockpit voice recorder panel increases the audio signal from the area microphone and sends it to the voice recorder unit.

You can monitor the voice recorder recorded audio if you connect a headphone to the phone jack at the cockpit voice recorder panel.

An erase switch on the voice recorder control panel removes all the audio that the voice recorder keeps. You can only erase data when the airplane is on the ground and the parking brake is set.

A test switch on the cockpit voice recorder panel starts a test of the voice recorder system. A status indicator LED on the cockpit voice recorder panel shows the results of the test.

An underwater locator beacon is on the front panel of the voice recorder unit.

General

The cockpit voice recorder panel is on the P5 forward overhead panel.

The voice recorder switch is on the P5 forward overhead panel.

The captain clock is on the P1 captain instrument panel.

General

The voice recorder unit is in the aft cargo compartment on the E6 rack.

Power

The time delay relay and the voice recorder switch get these voltages:

· 115v ac from the voice recorder circuit breaker

· 28v dc from the voice recorder relay circuit breaker.

The voice recorder gets 115v ac from either the time delay relay or the voice recorder switch. When the voice recorder switch is put to ON, the switch applies power to the voice recorder. A latching relay holds the switch in the ON position. This keeps the voice recorder power on for pre-flight checks.

When an engine starts, the latching relay opens. This returns the voice recorder switch to AUTO. At the same time, the time delay relay energizes. The time delay relay keeps 115v ac to the voice recorder.

When the engines are shut down, the time delay relay keeps the voice recorder on for an additional 5 minutes. This gives time for post-flight checks.

Дата добавления: 2015-10-23