Chapter 8-Flight Recorder Read-Out and Analysis

8-1 Initial response

8-2 Choice of facility

8-3 Participation by the State of manufacture (or design) and the State of the operator

8-4 Recommended procedures

Chapter 8

 Flight Recorder Read-Out and Analysis

8-1  Initial response

  1. The aftermath of a major accident is a demanding time for AAIU. One of the immediate items requiring a decision is where to have the flight recorders read out and analysed. It is essential that the flight recorders be read out as early as possible after an accident. Early identification of problem areas can affect the investigation at the accident site where evidence is sometimes transient. Early identification of problem areas may also result in urgent safety recommendations which may be necessary to prevent a similar occurrence.
  2. AAIU does not have its own facilities for the playback and analysis of flight recorder information (both voice and data) and consequently request assistance from other States. It is essential, therefore, that AAIU makes timely arrangements to read out the flight recorders at a suitable readout facility.


  1. AAIU may request assistance from any State that, in its opinion, can best serve the investigation. The manufacturer’s standard replay equipment and playback software, which is typically used by airlines and maintenance facilities, is not considered adequate for investigation purposes. Special recovery and analysis techniques are usually required if the recorders have been damaged.
  2. Facilities for the read-out of flight recorders should have the following capabilities:
  1. the ability to disassemble and read out recorders that have sustained substantial damage;
  2. the ability to play back the original recording/memory module without the need for the use of a manufacturer’s copy device or the recorder housing that was involved in the accident or incident;
  3. the ability to manually analyse the raw binary waveform from digital tape flight data recorders;
  4. the ability to enhance and filter voice recordings digitally by means of suitable software; and
  5. the capability to graphically analyse data, to derive additional parameters not explicitly recorded, to validate the data by cross-checking and other analytical methods to determine data accuracy and limitations.


  1. The State of Manufacture (or Design) has airworthiness responsibilities and the expertise normally required to read out and analyse flight recorder information. Since flight recorder information can often reveal airworthiness problems, the State of Manufacture (or Design) should have a representative present when the flight recorder read-out and analysis are being conducted in a State other than the State of Manufacture (or Design).
  2. The State of the Operator has regulatory responsibilities regarding the flight operation and can provide insights into operational issues which may be specific to the operator. Since flight recorder information can reveal operational problems, the State of the Operator should also have a representative present when the flight recorder read-out and analysis are being conducted.

8.4 Recommended Procedures

  1. The flight data recorder and the cockpit voice recorder should be read out by the same facility, because they contain complementary data which can help validate each recording and aid in determining timing and synchronization.
  2. Flight recorders should not be opened or powered up and original recordings should not be copied (particularly not by high-speed copy devices) prior to the read-out because of the risk of damage to the recordings.
  3. The facility at which the flight recorders are read out for another State should be given an opportunity to comment on the Final Report in order to ensure that the characteristics of the flight recorder analysis have been taken into account. 
    The facility at which the flight recorders are read out may require the expertise of the aircraft manufacturer and the operator in order to verify the calibration data and validate the recorded information.
  4. AAIU may leave the original recordings, or a copy of them, with the read-out facility until the investigation is completed, in order to facilitate the timely resolution of additional requests or clarifications, providing that the facility has adequate security procedures to safeguard the recordings.


Legislations & Regulations