From: NTSB
To: FAA
Date: 8/30/1982
Response: The board does not accept your assumption that cvr benefits accrue where safety improvements arise from accidents in which cause/factordata were obtainable from no source other than the cvr. We have never considered the information obtained from the cvr in isolation, but have used it primarily as a tool in uncovering (sometimes) subtle clues to assist us in determining probable cause and in making recommendations for preventing future accidents. More often than not, the raw cvr data has (1)provided extremely valuable clues to the cause, (2) allowed more rapid dissemination of safety information to operators, (3) established the sequence of events in the cockpit and the timing of critical events, and (4) in conjunction with the fdr, provided the basis for aircraft perform- ance analysis which, in turn, either uncovers or corroborates the probable cause and contributes to safety recommendations to prevent future accidents. . . . . Because of the factors discussed above, the safety board does not accept the faa’s cost benefit analysis as demonstrating that its recommendation is not feasible. We are, therefore, classifying recommenda-tion a-78-29 as closed–unacceptable action.