VDR data - Lost before it is found?
By Faz Peermohamed, Ince & Co., London
Voyage Data Recorder/Black box
The data obtained must be automatically downloaded and stored into a brightly coloured, often orange, protective memory capsule that has been hardened to withstand extreme fire, shock and water pressure conditions. VDRs are required to maintain a record of all data for a minimum of 12 hours (Class often requires 24 hours and many manufacturers provide a longer period), after which the information will be overwritten. To ensure a VDR continues to record events during and after an incident, it should be capable of operating from the ship’s emergency source of electrical power. In the event that this fails, a VDR should, as a minimum, continue to record bridge audio from a dedicated reserve source of power for a period of two hours. After two hours, all recording would generally cease automatically.
During many incidents, however, power sources will not be completely lost and the VDR will therefore continue to record events in the normal fashion (i.e., for a minimum of 12 hours before being overwritten). For the purposes of evidence collection, therefore, it is essential to identify quickly whether a vessel is fitted with a VDR and for those on board to retain or download the information it contains as soon as possible. Should all power be lost (for example when a vessel sinks or is lost to fire), a VDR will generally retain the last 12 hours (or more if set up to do so) as a final recording medium installed in a protective capsule. This will remain fixed to the vessel or, in the case of a more sophisticated black box, float free and transmit its position, via an EPIRB type signal, for SAR aircraft and/or ships to detect. In any event, the capsule should retain the data for a period of at least two years.
VDR data has its uses outside casualty situations. The data can also be retrieved and downloaded at any time (providing those on board have the designated software) for training purposes (following a close quarters situation, for example). However, as with some electronic chart systems, VDRs will often require a manufacturer’s technician to attend in order to download the data. In a casualty situation, therefore, it is important that the master preserves the data and, if necessary, that a technician is brought on site to access the data as soon as possible. It is precisely this “grey” area that is causing the current loss of valuable information. Numerous manufacturers and various model types requiring different software versions to be able to view the data make it difficult for even the expert technician to retrieve the information, let alone the crew, who may not have received training in obtaining/preserving data. The important thing to do is to stop the VDR overwriting data – retrieving can always be done at a later stage either by the crew or a technician.
Masters should be reminded, however, that the records will be overwritten (at times, once again, within 12 hours) if the data is not promptly saved. Masters would be well advised to familiarise themselves, and their bridge team, with the practicalities of data saving during quiet sea passages and include the saving of data as part of their emergency response procedures; such knowledge will need to be second nature in the aftermath of a casualty where time is of the essence. Owners/managers would also be advised to include such information within the emergency response section of the vessel’s Safety Management System (SMS). Often, however, the data will be saved in a format that is not readily accessible to a third party without the necessary software. Owners should check whether the information on their equipment can be readily downloaded or whether a manufacturer’s technician will be needed. If a technician is required, he should be put on stand-by to attend a casualty as soon as possible after an incident to extract the necessary evidence.
Some care should be taken when extracting the necessary evidence. Whilst preserving all available evidence, common sense should also prevail. For example, a common error is for a navigator to save the entire passage plan of a voyage, which may last some days, when the relevant section consists only of the last hour before the incident. Without wishing to discourage the extraction of evidence, it should be borne in mind that a huge data file, consisting of many days of voyage, is likely to crash the ECDIS during playback, or prove impossible to download without the aid of a technician when, really, it should be a task within the capability of those on board. One solution to prevent loss of electronic data is to have a simple A4 side instruction posted on the bridge, near the related recorder, e.g., the ECDIS. Further, when new officers join, this same instruction could be attached to their routine familiarisation checklist.
As with GPS, in the event of an incident AIS is again an extremely useful tool in terms of evidence collection. Some AIS systems have a data recording facility and masters should be encouraged to check their sets and familiarise themselves with the use of this facility, if fitted. If preserved, AIS data not only provides information about your own ship’s movements, but also about other vessels in the area, including those who may well have witnessed the incident, even if not directly involved. In such cases, it is important that, where possible, AIS data (along with any other electronic information) is saved as soon as possible after an incident has occurred because, as we have seen above, it is common for most electronic navigation equipment with recording facilities to only save data for a pre-set time period, after which the information is overwritten. Some caution should be exercised with AIS, however, as it has not proved infallible and indeed many older existing sets are prone to inaccuracies and errors of various data fields.
Gard News is published quarterly by Gard AS, Arendal, Norway.
- Load lines
- Tonnage measurement of ships
- Notice of Readiness and the commencement of laytime