Monday, December 3, 2012

CVR Signals to be recorded



         The CVR records the flight crew’s voices, as well as other sounds inside the cockpit. The recorder’s "cockpit area microphone" is usually located on the overhead instrument panel between the two pilots. Sounds of interest to an investigator could be engine noise, stall warnings, landing gear extension and retraction, and other clicks and pops.


CIVIL AVIATION REQUIREMENTS SECTION 2 - AIRWORTHINESS SERIES 'I' PART VI
ISSUE II, 14th November 2012


2. Cockpit Voice Recorder (CVR) & Cockpit Audio Recording System (CARS)
2.1 Signals to be recorded
        The CVR and CARS shall start to record prior to the aeroplane moving under its own
power and record continuously until the termination of the flight when the aeroplane is no longer capable of moving under its own power. In addition, depending on the availability of electrical power, the CVR and CARS shall start to record as early as possible during the cockpit checks prior to engine start at the beginning of the flight until the cockpit checks immediately following engine shutdown at the end of the flight.

2.1.1 The CVR shall record on four separate channels, or more, at least the
following:
a) voice communication transmitted from or received in the aircraft aeroplane by radio;
b) aural environment on the flight deck;
c) voice communication of flight crew members on the flight deck using the aero plane’s interphone system, if installed;
d) voice or audio signals identifying navigation or approach aids introduced in the headset or speaker; and
e) voice communication of flight crew members using the passenger address system, if installed
2.1.2 The CARS shall record on two separate channels, or more, at least the following:
a) voice communication transmitted from or received in the aeroplane by radio;
b) aural environment on the flight deck; and
c) voice communication of flight crew members on the flight deck using the
aeroplane’s interphone system, if installed.
2.1.3 The CVR shall be capable of recording - on at least four channels simultaneously. On a tape-based CVR, to ensure accurate time correlation between channels, the CVR is to record in an in-line format. If a bi-directional configuration is used, the in-line format and channel allocation shall be retained in both directions.
The preferred channel allocation shall be as follows:
Channel 1 — co-pilot headphones and live boom microphone
Channel 2 — pilot headphones and live boom microphone
Channel 3 — area microphone
Channel-4(Aero plane) — time reference plus the third and fourth crew members’
headphone and live microphone, if applicable.
Channel-4(Helicopters) – time reference, main rotor speed or the flight Deck
vibration environment, the third and fourth crew member's headphones and live
microphones, if applicable.
Note -1:- Channel 1 is located closest to the base of the recording head.
Note-2:- The preferred channel allocation presumes use of current conventional
magnetic tape transport mechanisms, and is specified because the outer edges of
the tape have a higher risk of damage than the middle. It is not intended to preclude
use of alternative recording media where such constraints may not apply.



CIVIL AVIATION REQUIREMENTS SECTION 2 - AIRWORTHINESS SERIES 'I' PART VI
ISSUE II, 14th November 2012 

Qualty,Safety and Training

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