Simfly asked:
"Are CVFDR's of the same size as FDR/CVR's, if so, do aircraft carry 1 CVFDR or 2 for redundancy?"
The answer to your question varies with installation and aircraft type. A CVFDR "Combined Voice/Data Recorder" both units fit into one 1/2 ATR chassis. Cockpit voice recorders can come in either a 1/2 ATR Chassis or a smaller package. We also offer 2 hrs of voice on seperate channels and up to 25 hours of flight data. The IDARS system combines CV/FDR and DFDAU all into one box, thus saving weight, space and LRU's and can be made into a full HUMS by adding the optional vibration card.
The DFDAU converts the analog signals; temps, torque, pressures etc. into digital signals for storage onto the FDR's crash survivable memory. In older installations (tape based) to have a CVR & FDR would require the aircraft to have up to three heavy LRU's (CVR, FDR & FDAU) weighing on average of 20+ pounds each! The IDARS combines all of those into one box at less than 17 pounds. A CVR only installation now weighs about 6 pounds for the LRU.
Check out the links below for more details regarding data recorders:
CVFDR VADR IDARS
Regards,
Chuck Kemp