Please feel free to browse and read the general data and information on Flight Data Recorders (FDR's) tape/solid state, Cockpit Voice Recorders (CVR's) tape/solid state, our current FDR/CVR capabilities, and see our service facility and meet some of the people who service this equipment.
Do you require a copy of a CVR Intelligibly Evaluation Flight and Ground Test procedures, if so please feel free to download one of the following, depending upon your application. Standard Two Crew version Heavy Aircraft version
Cockpit Voice Recorders (CVRs)
Cockpit voice recorders record either the last 30 minutes of audio, or the last 120 minutes of audio depending on the part number of the unit. Only solid state CVR's will record 120 minutes, but there are both tape based and solid state 30 minute recorders. Tape Units
Tape units use either an endless loop tape, or a stacked reel to reel with reversing motors. The recorders record continually writing over the oldest information.
Tape is becoming obsolete; most CVR manufacturers have only a limited amount of tape left in their inventories.
Only the tape mechanism is protected in the crash and fire protected module.
Tape based recorders require annual maintenance to ensure normal TBO times are met, and typically 4000 to 6000 hour overhauls Solid State
Solid state recorders employ non-volatile memory to store digitally recorded audio.
Only the memory is protected in the crash and fire protected module.
Solid state recorders are highly integrated and employ multiple microprocessors and programmable digital array chips. Intelligibility Evaluation
The CAR's require that an intelligibility evaluation be performed every 3000 hours or 12 months which ever occurs first.
The Intelligibility Evaluation confirms that the aircraft CVR system meets the minimum requirements.
First time installation of CVR's must have the intelligibility evaluation performed by an TCCA approved Initial Intelligibility Evaluation Centre. Pacific Avionics & Instruments is one of 3 approved facilities in Canada.
Flight Data Recorders (FDRs)
Flight Data recorders record at least the last 25 hours of flight information. Tape based units employ either an endless multitrack tape, or a reel to reel multitrack tape. The flight data is recorded digitally in a serial data stream on the tape.
The number of flight parameters recorded is dependant upon the vintage and size of the aircraft. The most basic system record as few as 5 parameters, the most complex records thousands of parameters.
Some FDR contain the digital to analogue converters (ARINC 542), other recorders accept data from a FDAU (ARINC 573, 717, 747). Tape Units
The flight data is converted to digital data and then recorded onto tape serially. The tape is organized into tracks. New data is recorded over the oldest data, preserving at least 25 hours of flight data.
Only the tape mechanism is protected in the crash and fire protected module. Solid State Units
The flight data is stored in non-volatile memory.
The solid state recorders record the parameters that change during a flight. If the aircraft is in cruise flight many parameters are stable and not changing, memory is conserved, thus solid state recorders store much more than 25 hours of flight data.
Solid state recorders are much lighter than tape based recorders. The latest generation are sometimes as much as 40% lighter. Flight Data Readouts
Here in Canada, the Canadian Air Regulations require that a Correlation check be done every 3000 hours or 12 months which ever occurs first to ensure all required parameters are being recorded and usable. This is usually done by a readout of the last flight recorded by the FDR. The readout allows the Maintenance crew to confirm that the data is valid and representative of the last flight. Depending on the number of parameters recorded, and the duration of the flight the report can be many hundreds of pages long.