Doc 10104, Manual on Flight Recorder System Maintenance (FRSM). First edition, 2020.
Some States’ accident investigation authorities regularly experience problems during the download of flight data recorders (FDRs) due to the unavailability of data frame information. Similarly, challenges were encountered due to cockpit voice recorders (CVRs) that were not operational during accidents and incidents. Annex 6 — Operation of Aircraft, Part I — International Commercial Air Transport — Aeroplanes, 6.3.5.3 requires that operational checks and evaluations of recordings from flight recorder systems be conducted to ensure the continued serviceability of the recorders.
The procedures for these checks and evaluations, found in Appendix 8 of Annex 6, Part I and similar provisions in Part II — International General Aviation — Aeroplanes and Part III — International Operations — Helicopters, are not sufficient and further guidance material is needed. In addition, the procedures may not be translated into equipment maintenance requirements produced by the manufacturers. Similar concerns were raised during the Accident Investigation and Prevention (AIG) Divisional Meeting (2008) (AIG/08) which resulted in Recommendation 2/4 for the Air Navigation Commission to note the concerns raised by AIG/08.
Relevant guidance material exists in some States such as the United Kingdom CAP 731 document and similar recorder maintenance documents from Australia, France, United States, European Union Aviation Safety Agency (EASA) and others. However, it was deemed beneficial to have such guidance material in an ICAO document available to States and hence this document was developed by the Flight Recorder Specific Working Group of the Flight Operations Panel.