cvr notes

7/27/2019 CVR notes

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CVR

Cockpit Voice Recorder (CVR): It is a flight recorder installed in the aircraft for the purpose of recording the aural environment on the flight deck during flight time for the purpose of accident/incident prevention and investigation.Cockpit Audio Recording System (CARS): It is a lightweight flight recording system installed inthe aircraft for the purpose of recording the voice communication transmitted from or received inthe aeroplane by radio and also the aural environment on the f light deck during flight time for thepurpose of accident/ incident prevention and investigation.

System Description and LimitationsThe Cockpit Voice Recorder system has been designed to meet or exceed those requirementsspecified within and is approved under Federal Aviation Administration Technical Standard Order C84 or C111.

The Cockpit Voice Recorder system is composed of three essential components: the Recorder Unit, Control Unit Components with area microphone module, and Vibration Mount. A Heavy –DutyVibration Mount is available for rotorcraft installations.

The CVR simultaneously records four separate voice inputs. These inputs may be either

transmitted or received signals originating from the following recommended stations: Pilot, Co –Pilot, Public Address or Third Crew Member, and Cockpit Area Microphone.

7/27/2019 CVR notes


1. Recorder Recorder is design to recorder at least following-

1. Voice communication transmitted or received in aircraft from radio.2. Aural environment on flight deck.3. Voice communication of flight crew using flight interphone.4. Voice or audio signals identifying navigation approach aid introducing in headset.5. Voice communication of flight crew using PA system.

Recorder container description-

1. The recorder is housed in an international orange/vermilion colour, 1/2 ATR short case. It contains

the recorder assembly and associated electronics.

2. Carry reflective material to facilitate its location.

3. Have securely attached with under water locating beacon.

4. Be shock , temp, & fire proof.

Performance required

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Equipment Limitation & Specifications-1. Designed to FAA TSO (Technical standard order)–C84 & C111.2. Size ½ ATR case.3. Colour International orange / Vermilion colour.4. TAPE- ¼” pre-conditioned myler base recording endless tape.5. Recording Duration: Minimum 30mnts.6. Bulk erase – disabled7. Freq respond to 150Hz to 5000Hz +/- 3db.

ULB (under water Beacon)-The beacon is a battery-powered device, which radiates a pulsed acoustic signal into thesurrounding water upon activation by its water-sensitive switch pins located at each end of theBeacon.

BEACON SPECIFICATIONS

Operating Frequency 37.5Khz+/-1Khz

Operating Depth 6096Meters

Pulse Length 10milisecond +/- 10%

Operating life 30Days (min)

Battery life in beacon 60Days

Actuation Fresh or salt water

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Control PanelThe control units are standard ARINC characteristic panel. It consist of preamplifier

microphone, test switch, erase switch, Go-No-Go meter & 600 Ohms Jack for external

headset for recording & Testing purpose.

1. Go-No-Go Test Meter- whenever test button pressed should go in green arc to pass test.2. Test Switch- press to test & check indication on Go-No-Go Meter.3. Erase Switch- A push-button switch placard ERASE is used to erase all recordings after a

routine flight. The erase switch will only work when the weight of the aircraft is on the landinggear. To prevent accidental erasures, a time-delay circuit makes it necessary to hold theerase switch pressed for 2 seconds before the erasure process will begin

4. Headset Jack- A jack placard Headset 600 OHMS allows playback of all four recordingchannels simultaneously.

7/27/2019 CVR notes


Pre-Flight Functional Check

1.The Pre-flight Functional Check assures the operator that the equipment is serviceable.Therefore, it is to be performed before every flight or whenever maintenance has been performed

on the aircraft or rotorcraft which may have affected the performance of the Cockpit Voice

Recorder or its associated Audio System interface, accessories, or components.

2.Push and hold “Test” button located on the Cockpit Control Unit for a minimum of five seconds. A600 hertz generator is keyed and sequentially switched through the four channels of the recorder.Each channel receives the test tone for approximately 0.8 seconds. The meter circuit receivesthese signals and drives the meter, a ’GO–NO –GO” indicating device, located on the CockpitControl Unit. The meter needle rises and comes to a rest in the ’GO’ (green) section of the meter scale.

Because of the short time interval between each channel being fed the test tone, the meter needlerises to an indication but does not completely fall to a zero indication between signals, giving moreof an oscillating action or a slight dithering action. In the event of a channel failure, the meter needle will fall out of the green section of the meter scale or return to zero and give a definite ’NO–GO’ indication.

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