IEC 61996:2000

INTERNATIONAL IEC
STANDARD
First edition
2000-07
Maritime navigation and radiocommunication
equipment and systems –
Shipborne voyage data recorder (VDR) –
Performance requirements –
Methods of testing and required test results
Matériels et systèmes de navigation et
de radiocommunication maritimes –
Enregistreurs de données de voyage (VDR) de bord –
Exigences de fonctionnement –
Méthodes d'essai et résultats d'essai exigés

Reference number
Numbering
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60000 series.
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available. For example, edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the
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publication incorporating amendments 1 and 2.

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thus ensuring that the content reflects current technology.
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Terminology, graphical and letter symbols
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Electrotechnical Vocabulary (IEV).
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general use, readers are referred to publications IEC 60027: Letter symbols to be
used in electrical technology, IEC 60417: Graphical symbols for use on equipment.
Index, survey and compilation of the single sheets and IEC 60617: Graphical symbols
for diagrams.
* See web site address on title page.

INTERNATIONAL IEC
STANDARD
First edition
2000-07
Maritime navigation and radiocommunication
equipment and systems –
Shipborne voyage data recorder (VDR) –
Performance requirements –
Methods of testing and required test results
Matériels et systèmes de navigation et
de radiocommunication maritimes –
Enregistreurs de données de voyage (VDR) de bord –
Exigences de fonctionnement –
Méthodes d'essai et résultats d'essai exigés

 IEC 2000  Copyright - all rights reserved
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For price, see current catalogue

– 2 – 61996 © IEC:2000(E)
CONTENTS
Page
FOREWORD . 3

Clause
1 Scope . 4

2 Normative references . 4

3 Definitions and abbreviations. 5

4 Performance requirements . 7
4.1 General. 7
4.2 Purpose (A.861/1) . 7
4.3 Operational requirements (A.861/5). 7
4.4 Data selection and security (A.861/5.1.4). 9
4.5 Continuity of operation . 10
4.6 Data items to be recorded (A.861/5.4) . 10
5 Technical characteristics . 12
5.1 Co-relation in date and time (A.861/5.1.2 and 5.4.1) . 12
5.2 Particular design requirements for the protective capsule . 12
5.3 Location beacon(s) for the protective capsule . 13
5.4 Survivability of recorded data . 13
5.5 Information to be included in the manufacturer’s documentation . 14
5.6 Bridge audio specifications. 15
5.7 Communications audio . 16
5.8 Radar data – post-display selection . 16
6 Methods of testing and required test results. 17
6.1 General. 17
6.2 (4.6) Data items to be recorded . 23
Annex A (informative) IEC 61162 sentence formats. 38
Annex B (informative) Mandatory alarms. 39
Annex C (informative) Requirement/test – cross-references . 41
Bibliography . 42
Figure 1 – Test set-up block diagram . 31

Figure 2 – Comparison of images . 35
Table 1 – Bridge audio, signal-to-no signal measurements . 25
Table 2 – Bridge audio, signal-to-noise and distortion (SINAD) measurements . 26
Table 3 – Communications audio, signal-to-no signal measurements . 28
Table 4 – Communications audio, signal-to-noise and distortion (SINAD) measurements. 29
Table 5 – Intersection colours of test images 1 and 2 . 33
Table A.1 – References in this standard. 38
Table B.1 – IMO instrument: SOLAS Chapter II-1. 39
Table B.2 – IMO instrument: SOLAS Chapter II-2. 40
Table B.3 – IMO instrument: Resolution A.481 . 40
Table C.1 – Subject list and clauses . 41

61996 © IEC:2000(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
MARITIME NAVIGATION AND RADIOCOMMUNICATION

EQUIPMENT AND SYSTEMS –
Shipborne voyage data recorder (VDR) –

Performance requirements –
Methods of testing and required test results

FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall be not held responsible for identifying any or all such patent rights.
International Standard IEC 61996 has been prepared by IEC technical committee 80: Maritime
navigation and radiocommunication equipment and systems.
The text of this standard is based on the following documents:
FDIS Report on voting
80/248/FDIS 80/273/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.
Annexes A, B and C are for information only.
The committee has decided that the contents of this publication will remain unchanged
until 2006. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this standard may be published at a later date.

– 4 – 61996 © IEC:2000(E)
MARITIME NAVIGATION AND RADIOCOMMUNICATION

EQUIPMENT AND SYSTEMS –
Shipborne voyage data recorder (VDR) –

Performance requirements –
Methods of testing and required test results

1 Scope
This International Standard specifies the minimum performance requirements, technical

characteristics and methods of testing, and required test results, for shipborne voyage data
recorder (VDR) installations as required by chapter V of the International Convention for Safety
of Life at Sea (SOLAS), as amended. It takes account of IMO resolution A.694 and is
associated with IEC 60945. When a requirement in this standard is different from IEC 60945,
the requirement in this standard takes precedence.
This standard incorporates the applicable parts of the performance standards included in IMO
Resolution A.861.
NOTE  All text of this standard, whose wording is identical to that of IMO Resolution A.861, is printed in italics, and
the Resolution and associated performance standard paragraph numbers are indicated in brackets.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this International Standard. For dated references, subsequent
amendments to, or revisions of, any of these publications do not apply. However, parties to
agreements based on this International Standard are encouraged to investigate the possibility
of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of IEC
and ISO maintain registers of currently valid International Standards.
IEC 60068-2-27:1987, Environmental testing – Part 2: Tests – Test Ea and guidance: Shock
IEC 60268-16:1998,
Sound system equipment – Part 16: Objective rating of speech intelligi-
bility by speech transmission index
IEC 60651:1979, Sound level meters
IEC 60945:1996, Maritime navigation and radiocommunication equipment and systems –
General requirements – Methods of testing and required test results
IEC 61097-2:1994, Global maritime distress and safety system (GMDSS) – Part 2: COSPAS-

SARSAT EPIRB – Satellite emergency position-indicating radio beacon operating on 406 MHz –
Operational and performance requirements, methods of testing and required test results
IEC 61097-5:1997, Global maritime distress and safety system (GMDSS) – Part 5: Inmarsat-E –
Emergency position-indicating radio beacon (EPIRB) operating through the Inmarsat system –
Operational and performance requirements, methods of testing and required test results
IEC 61097-7:1996, Global maritime distress and safety system (GMDSS) – Part 7: Shipborne
VHF radiotelephone transmitter and receiver – Operational and performance requirements,
methods of testing and required test results
IEC 61162 (all parts), Maritime navigation and radiocommunication equipment and systems –
Digital interfaces
IEC 61260:1995,
Electroacoustics – Octave-band and fractional-octave-band filters

61996 © IEC:2000(E) – 5 –
IMO A.658:1989, Use and fitting of retro-reflective materials on life-saving appliances

IMO A.662:1989, Performance standards for float-free release and activation arrangements for

emergency radio equipment
IMO A.689:1991, Testing of life saving appliances

IMO A.694:1991, General requirements for shipborne radio equipment forming part of the

Global maritime distress and safety system (GMDSS) and for electronic navigational aids

IMO A.810:1995, Performance standards for float-free satellite emergency position-indicating

radio beacons (EPIRBs) operating on 406 MHz

IMO A.812:1995, Performance standards for float-free satellite emergency position-indicating
radio beacons (EPIRBs) operating through the geostationary INMARSAT satellite system on
1,6 GHz
IMO A.830:1995, Code on alarms and indicators
IMO A.861:1997, Performance standards for shipborne voyage data recorders (VDRs)
IMO:1974, Convention on Safety of Life at Sea (SOLAS), as amended
ITU-R M.632-3:1997, Transmission characteristics of a satellite emergency position-indicating
radio beacon (satellite EPIRB) system operating through geostationary satellites in the 1,6 GHz
band
ITU-R M.633-1:1990, Transmission characteristics of a satellite emergency position-indicating
radiobeacon (satellite EPIRB) system operating through a low polar-orbiting satellite system in
the 406 MHz band
Eurocae: ED56A – Minimum operational performance specification (MOPS) for cockpit voice
recorder system
VESA:1996, Video electronics standards association – Discrete monitor timings standard 1.0,
Revision 0.7 (DMTS)
SAE AS8045:1988, Engineering Society for advancing mobility land sea air and space –
Minimum performance standard for underwater locating devices – acoustic-self-powered
3 Definitions and abbreviations
3.1 Definitions
3.1.1
recorder (VDR) (A.861/4.1)
complete system, including any items required to interface with the sources of input data, for
processing and encoding the data, the final recording medium in its capsule, the power supply
and dedicated reserve power source
3.1.2
sensor (A.861/4.2)
any unit external to the VDR to which the VDR is connected and from which it obtains data to
be recorded
3.1.3
final recording medium (A.861/4.3)
item of hardware on which the data is recorded such that access to it would enable the data to
be recovered and played back by use of suitable equipment

– 6 – 61996 © IEC:2000(E)
3.1.4
playback equipment (A.861/4.4)

equipment, compatible with the recording medium and the format used during recording,

employed for recovering the data. It includes also the display or presentation hardware and

software that is appropriate to the original data source equipment. Playback equipment is not

normally installed on a ship and is not regarded as part of a VDR within this standard

3.1.5
dedicated reserve power source (A.861/4.5)

secondary battery, with suitable automatic charging arrangements, dedicated solely to the

VDR, of sufficient capacity to operate it as required by 4.5.3

3.1.6
resolution
smallest detectable increment between two values
3.1.7
data
any item of information received by the VDR for recording, including numerical values, text and
audio or radar signals, except where specifically stated or the context dictates otherwise
3.1.8
activation of a suitable alarm
mutable audible alarm and persistent visual indication, given according to the requirements of
A.830, but with an audible level in the range of 55 dBA to 65 dBA
3.1.9
bridge work station
position at which a person is expected to be when performing one of the normal bridge duties
at, for example, the following work stations:
• centre line conning
• bridge wing(s)
• main radar
• chart table
• helmsman
• communication
3.2 Abbreviations
EPFS electronic position-fixing system

IMO International Maritime Organization
INS integrated navigation system
ITU International Telecommunication Union
OOW officer of the watch
ROV remotely operated vehicle
SENC system electronic navigation chart
SINAD signal to noise and distortion
STI sound transmission index
61996 © IEC:2000(E) – 7 –
4 Performance requirements
4.1 General
Performance requirements described in this clause are specified by reference to the numbered

paragraphs of IMO Resolution A.861.

4.2 Purpose (A.861/1)
The purpose of a Voyage Data Recorder (VDR) is to maintain a store, in a secure and

retrievable form, of information concerning the position, movement, physical status, command

and control of a vessel over the period leading up to, and following, an incident having an
impact thereon. This information is for use during any subsequent investigation to identify the
cause(s) of the incident.
4.3 Operational requirements (A.861/5)
4.3.1 Design and construction (A.861/5.1.4)
The design and construction, which shall be in accordance with the requirements of resolution
A.694(17) and international standards acceptable to the International Maritime Organization
(IMO), shall take special account of the requirements for data security and continuity of
operation as detailed in 4.4 and 4.5.
4.3.2 Maintenance of sequential records (A.861/5.1.1)
The VDR shall continuously maintain sequential records of pre-selected data items relating to
the status and output of the ship's equipment, and command and control of the ship, referred to
in 4.6.
4.3.3 Co-relation in date and time (A.861/5.1.2, 5.4.1)
To permit subsequent analysis of factors surrounding an incident, the method of recording shall
ensure that the various data items can be co-related in date and time during playback on
suitable equipment.
The recording method shall be such that the timing of all recorded data items can be derived
on playback with a resolution sufficient to reconstruct the history of an incident in detail
(see 4.6.1).
4.3.4 Protective capsule (A.861/5.1.3)

4.3.4.1 Final recording medium
The final recording medium shall be installed in a protective capsule. The capsule shall meet
all the requirements of 4.3.4.2 and 4.3.4.3.
4.3.4.2 (A.861/5.1.3.1)  The capsule shall be capable of being accessed following an incident
but secure against tampering
The capsule shall enclose the final recording medium. The final recording medium shall not be
accessible by standard operating procedures during normal ship operations.
A means shall be provided to retrieve stored information via an external device without opening
the protective capsule.
– 8 – 61996 © IEC:2000(E)
4.3.4.3 (A.861/5.1.3.2) Recovery

The capsule shall maximise the probability of survival and recovery of the final recorded data

after any incident (see 5.2).
4.3.4.3.1 Structure of the capsule

The capsule containing the final recording medium shall be designed to be installed on the

external deck of the vessel. It may be designed to remain fixed to the ship in all circumstances.

Alternatively, it may be designed to float free automatically if the ship sinks (see 5.2).

The capsule shall be designed to protect the stored data against the following (see 5.4):
• shock
• penetration
• fire
• deep-sea pressure and immersion
4.3.4.3.2  Visibility and marking (A.861/5.1.3.3)
The capsule, together with any outermost shell, shall be of a highly visible fluorescent orange
colour, marked with retro-reflective materials that comply with the relevant requirements of IMO
A.658 and marked with the legend:
“VOYAGE DATA RECORDER – DO NOT OPEN –
REPORT TO AUTHORITIES”
4.3.4.3.3 (A.861/5.1.3.4) Location
The capsule shall be fitted with an appropriate device to aid location.
Both fixed and floatfree designs shall include an acoustic underwater beacon. In the case of a
protective capsule intended for float-free operation, it shall also have a suitable radio
transmitter, and a light (see 5.3).
4.3.5 Assessment of recording medium
Where the storage medium cannot be readily and reliably inspected after an incident, means
shall be provided to enable an accident investigator to determine, prior to an attempted replay,
whether the storage medium has been subjected to an excessive level of heat, where the

survival of the stored data may be in doubt.
4.3.6 Interfaces (A.861/7)
Interfacing to the various sensors required shall be in accordance with the relevant
international interface standard, IEC 61162 series, where possible (see annex A).
The interfaces for bridge audio, communications audio and radar are defined in 5.6.1, 5.7.1
and 5.8.1 respectively.
Any interface units which may be required to convert non-IEC 61162 signals, shall conform to
the requirements of IEC 60945.
In all cases, any connection to any item of the ship's equipment shall be such that the
operation of that equipment suffers no deterioration, even if the VDR system develops faults.

61996 © IEC:2000(E) – 9 –
4.4 Data selection and security (A.861/5.1.4)

4.4.1 Selection of data items (A.861/5.2.1)

The minimum selections of operational data items to be recorded by the VDR are specified
in 4.6. Optionally, additional items may be recorded provided that the requirements for the
recording and storage of the specified selections are not compromised.

In addition to the operational data referred to in the preceding paragraph, a data block defining
the configuration of the VDR and the sensors to which it is connected shall be written into the

final recording medium during commissioning of the VDR. This configuration data shall be

permanently retained in the final recording medium and protected from modification other than

by a duly authorised person following any change to the configuration. Any change to the
configuration of this data block shall not affect the recording of the mandatory items.
The following system configuration information and data source identity shall be included in this
data block:
a) type approval authority and reference;
b) IMO vessel identification number;
c) software version(s) used;
d) microphone locations and recording port allocation;
NOTE This does not imply channelization.
e) VHF communications – which VHF(s) recorded;
f) date and time – from which source obtained;
g) ship’s position – from which EPFS obtained and relative position on the vessel;
h) other data inputs – identification of which equipment is supplying recorded data; sign
conventions and identity of all alarm/door inputs;
i) automatic insertion of date and time of last amendment.
4.4.2 Resistance to tampering (A.861/5.2.2)
The equipment shall be so designed that, as far as is practical, it is not possible to tamper with
the selection of data being input to the equipment, the data itself nor that which has already
been recorded. Any attempt to interfere with the integrity of the data or the recording shall be
recorded.
4.4.3 Recording integrity (A.861/5.2.3)
The recording method shall be such that each item of the recorded data is checked for

integrity, i.e. it is identical to the data being received, and an alarm given if a non-correctable
error is detected.
The VDR shall automatically continuously monitor the following (see 6.1.10):
a) power supply;
b) record function;
c) bit error rate;
d) microphone functionality.
Malfunction of any of the above shall generate an alarm in accordance with the relevant
requirements of IMO A.830 at the position from which the vessel is normally navigated. It shall
be possible to mute the alarm but a visual indication shall remain until the equipment is
serviceable. It shall also indicate its alarm status by means of contacts of a relay (or
equivalent) which is held energised in the no-alarm condition.

– 10 – 61996 © IEC:2000(E)
4.5 Continuity of operation
4.5.1 Operation (A.861/6)
The unit shall be entirely automatic in normal operation. Means shall be provided to ensure that
the recorded data may be saved by an appropriate method following an incident, with minimal
interruption to the recording process and without requiring opening of the protective capsule.

a) Controls for use during the saving process shall be simple to use.

b) The recording process to the final recording medium shall not be interrupted for more than

10 min during the saving process. The data recorded in the final recording medium shall not

be erased.
c) The data saved shall be automatically checked to ensure that it is identical to the recorded
data on the final recording medium. Any failure shall be indicated.
d) When the saving process is completed, means shall be provided to enable copies to be
made of this or of data relating to subsequent incidents.
NOTE  “saving process” – means – preserving a copy of the data contained in the final recording medium.
4.5.2 Power source (A.861/5.3.1)
To ensure that the VDR continues to record events during an incident, it shall be capable of
operating from the ship's emergency source of electrical power. Whenever electrical power is
available the VDR shall operate, except as permitted in 4.5.4 (see 6.1.15).
4.5.3 Reserve power source (A.861/5.3.2)
If the ship's emergency source of electrical power supply fails, the VDR shall continue to record
bridge audio (see 4.6.5) from a dedicated reserve source of power for a period of 2 h. At the
end of this 2 h period all recording shall cease automatically.
4.5.4 Recording period and duration (A.861/5.3.3)
Recording shall be continuous unless interrupted briefly in accordance with 4.5.1 or terminated
in accordance with 4.5.3. The time for which all stored data items are retained shall be at least
12 h. Data items which are older than this may be overwritten with new data.
Recording may also be terminated, by means of a key or other secure method.
NOTE This may occur under the following circumstances:
a) during essential maintenance purposes whilst the vessel is in port;
b) when the vessel is laid-up.

4.6 Data items to be recorded (A.861/5.4)
4.6.1 Date and time (A.861/5.4.1)
Date and time referenced to UTC, shall be obtained from a source external to the ship (for
example, an EPFS or radio time signal) if available, or from an internal clock at least once per
hour. The recording shall indicate which source is in use. The recording method shall be such
that the timing of all other recorded data items can be derived on playback with a resolution
sufficient to reconstruct the history of the incident in detail, not worse than 1 s.
4.6.2 Ship’s position (A.861/5.4.2)
Latitude and longitude, and the datum used, shall be derived from a designated EPFS or INS if
available. The recording shall ensure that the identity and status of the source can always be
determined on playback. The ship’s position shall be recorded, as available on the ship, up to a
resolution of 0,0001 min of arc.

61996 © IEC:2000(E) – 11 –
4.6.3 Speed (A.861/5.4.3)
Speed through the water, or speed over the ground (transverse as well as longitudinal in either

case, as available on the ship), including an indication from which it is derived, from the ship’s

designated speed and distance measuring equipment, shall be recorded, as available on the

ship, up to a resolution of 0,1 knots.

4.6.4 Heading (A.861/5.4.4)
As indicated by a designated ship's compass. The ship’s heading shall be recorded, as

available on the ship, up to a resolution of 0,1°.

4.6.5 Bridge audio (A.861/5.4.5)
One or more microphones positioned on the bridge shall be placed, such that conversation at
or near the conning stations, radar displays, chart tables, etc. (i.e. at work stations as defined
in 3.1.9) may be adequately recorded. As far as is practicable, the positioning of microphones
shall also capture the input and output of intercom, public address systems and the audible
alarms on the bridge (bridge mounted equipment) (see 5.6 for technical characteristics).
The audio signals at all work stations shall be recorded continuously. Optionally, means may
be provided so that the originating work station can be identified with the audio signal being
analysed during playback of the recorded information.
4.6.6 Communications audio (A.861/5.4.6)
VHF communications relating to ship operations shall be recorded, independently of the bridge
audio. The recording shall include both transmitted and received audio signals and shall be
continuous from a directly connected fixed VHF set to be designated at installation (see 5.7 for
technical characteristics).
4.6.7 Radar data – post-display selection (A.861/5.4.7)
This shall include electronic signal information from within one of the ship's radar installations
which records all the information which was actually being presented on the master display of
that radar at the time of recording. This shall include any range rings or markers, bearing
markers, electronic plotting symbols, radar maps, whatever parts of the SENC or other
electronic chart or map that were selected, the voyage plan, navigational data, navigational
alarms and the radar status data that were visible on the display. The recording method shall
be such that, on playback, it is possible to present a faithful replica of the entire radar display
that was on view at the time of recording, albeit within the limitations of any bandwidth
compression techniques that are essential to the working of the VDR (see 5.8).

4.6.8 Echo sounder (A.861/5.4.8)
This shall include depth under keel, up to a resolution of 0,1 m as available on the ship. The depth
scale currently being displayed and other status information shall be recorded where available.
4.6.9 Main alarms (A.861/5.4.9)
This shall include the status of all IMO mandatory alarms on the bridge (see annex B).
The status of all IMO mandatory alarms shall be recorded by the bridge audio and as a data
parameter where practicable.
– 12 – 61996 © IEC:2000(E)
4.6.10 Rudder order and response (A.861/5.4.10)

Both rudder order and response angles shall be recorded up to a resolution of 1° as available

and permitted on the ship. Status and settings of heading or track controller, if fitted, shall also

be recorded.
4.6.11 Engine order and response (A.861/5.4.11)

This shall include the positions of any engine telegraphs or direct engine/propeller controls,
including shaft(s) r.p.m. (or equivalent), and feedback indications, if fitted, including ahead/

astern indicators. This shall also include status of bow and stern thrusters if fitted. RPM shall

be recorded up to a resolution of 1 r.p.m. and pitch shall be recorded up to a resolution of 1°.

4.6.12 Hull openings (doors) status (A.861/5.4.12)
This shall include all IMO mandatory status information required to be displayed on the bridge.
4.6.13 Watertight and fire door status (A.861/5.4.13)
This shall include all IMO mandatory status information required to be displayed on the bridge.
4.6.14 Accelerations and hull stresses (A.861/5.4.14)
Where a ship is fitted with IMO mandated hull stress and response monitoring equipment, all
the data items that have been pre-selected within that equipment and are available shall be
recorded.
4.6.15 Wind speed and direction (A.861/5.4.15)
This shall be applicable where a ship is fitted with a suitable sensor. Either relative or true wind
speed and direction may be recorded, but an indication of which it is shall be recorded.
5 Technical characteristics
5.1 Co-relation in date and time (A.861/5.1.2 and 5.4.1)
To ensure that relative timings can be determined within a resolution of 0,1 s, all data items
shall, when sampled by the VDR, be recorded with a time index derived from a VDR system
clock with a resolution of 0,05 s. The drift of this system clock shall be not more than 1 s in 1 h.
5.2 Particular design requirements for the protective capsule

Where a float-free release mechanism is used, it shall comply with the relevant requirements of
IMO Resolution A.662.
Any float-free release mechanism shall be inhibited automatically if the protective capsule has
been subjected to a fire temperature more severe than the fire protection of the radio
transmission device required by 4.3.4.3.3.
Both float-free and fixed designs shall have a release mechanism to facilitate recovery under
water both by a diver or a remotely operated vehicle (ROV). Possible items to be considered
are:
a) the use of break-away bolts;
b) release levers; or
c) twist lock.
61996 © IEC:2000(E) – 13 –
To ensure that the capsule may be retrieved safely after release, suitable large pad eyes or

handles should be incorporated.

NOTE  It should be borne in mind that the manipulator jaws of typical underwater recovery machines have a
maximum opening of only 300 mm, a gripping force limit of about 1 kN, and a pulling force limit of about 500 N.

5.3 Location beacon(s) for the protective capsule

These shall include an acoustic underwater beacon operating in the frequency band of 25 kHz

to 50 kHz with a battery life of at least 30 days, which shall meet SAE AS 8045.

In the case of a protective capsule intended for float-free operation, it shall also have a suitable

radio transmitter, complying with appropriate international resolutions and recommendations,
to transmit signals suitable for location purposes, for example, IMO A.810, IMO A.812,
ITU-R M.632-3 and ITU-R M.633-1. It shall also have a light conforming to the appropriate
requirements of IMO A.689. The battery life for both the radio and light functions shall be at
least seven days.
The buoyancy characteristics of a float-free protective capsule shall ensure that the radio
antenna will radiate an essentially hemispherical and vertically polarised signal. The float-free
protective capsule shall be designed so that a usable signal is provided in, at least, open sea
state 7 (equivalent to Beaufort wind-scale 10).
5.4 Survivability of recorded data
5.4.1 Long-term retention under normal conditions
The final recording medium shall retain the recorded data for a period of at least two years,
following termination of recording, under operational and storage conditions specified by the
equipment manufacturer. Consideration should be given to the distribution of data within
the recording medium.
5.4.2 Survival following an incident
The capsule shall be designed to ensure that the data held in the final recording medium, shall
be retrieved without loss after it has been subjected to the following conditions:
a) Shock
A half sine-wave pulse of 50 g, with a duration of 11 ms, as specified in table II of
IEC 60068-2-27.
b) Penetration
A mass of 250 kg with a pin of 100 mm diameter, dropped from a height of 3 m, as

specified in 5.3.2b of ED56A.
c) Fire
A low temperature fire of 260 °C nominal for 10 h, as specified in 5.3.2e of ED56A.
A high temperature fire of 1 100 °C nominal for 1 h, as specified in 5.3.2d of ED56A.
d) Deep-sea pressure and immersion
Immersion in sea water at a pressure of 60 MPa (equivalent to a depth of 6 000 m), as
specified in 5.3.2f of ED56A.
– 14 – 61996 © IEC:2000(E)
5.5 Information to be included in the manufacturer’s documentation

5.5.1 Installation guidelines
a) Siting of the protective capsule

The protective capsule shall be sited in the vicinity of the bridge on the external deck area

of the vessel so as to maximise the probability of its survival and recovery following an

incident. The capsule shall be positioned clear of rigging and other potential obstructions

and as near to the centreline of the ship as practically possible.

Criteria to be considered when assessing the optimum position shall include but not be

limited to the following:
1) separation from fuel or other potential fire sources,
2) separation from probable sources of mechanical damage,
3) operational environment for continued serviceability,
4) accessibility for copying of recorded data and for routine maintenance,
5) facilitation of underwater removal and retrieval by both divers and ROVs. There shall be
a clear unobstructed space in the vicinity of the capsule to allow an ROV or diver to
work,
6) in the case of float-free configuration, minimisation of the risk of obstruction after
release;
b) Siting of microphones;
c) Siting of all other components of the VDR configuration;
d) Entering and updating the static configuration data of 4.4.1;
e) The requirement for interface units to comply with 4.3.6.
5.5.2 Operation and maintenance manual
The manual shall include the following:
a) instructions on normal operation of the VDR;
b) instructions on how to copy data from the equipment;
c) instructions on the action to be taken following the activation of any VDR alarm;
d) instructions for downloading and verification of the final recording medium data. These
should be carried out whenever maintenance or repair has been carried out on any sensor
or on the VDR itself, or at least annually;
e) maintenance tasks required to ensure the serviceability and continued seaworthiness of the
VDR. An analysis shall be performed by the equipment installer to identify those sensors or

transducers where the serviceability or accuracy could be degraded and remain undetected.
The maintenance tasks to be performed shall take account of this analysis by requiring
appropriate functional and calibration checks at suitable intervals.
5.5.3 Information for use by an investigation authority
The following shall be available:
a) instructions to enable an investigation authority to manufacture any special tools or
interface equipment required for retrieval of recorded data from the recorder;
b) details of the necessary actions to be followed for data retrieval from an undamaged
protective capsule;
c) details of the necessary actions to be followed for data retrieval from a protective capsule
that has been damaged in an incident;
d) details of software required to enable playback of recorded data.

61996 © IEC:2000(E) – 15 –
5.6 Bridge audio specifications

5.6.1 Input interface
The microphones forming the bridge audio data source are to be considered to be parts of
the VDR. The form of the connections, signal levels and impedances, are at the option of the
manufacturer. However, for the purposes of testing, each microphone shall be connected via a

plug/socket combination, which is referred to hereinafter as an input port.

5.6.2 Reference signal
The manufacturer shall declare a reference signal, for each microphone input, at the electrical

input port of the VDR. This shall be defined as a 1 kHz sinusoid at the maximum level for which
the equipment is designed to meet this performance specification.
5.6.3 Audio frequency response
Signal levels of both 6 dB and 45 dB below the reference signal level, shall be applied to every
bridge area microphone input port in turn, With the frequency swept continuously at a rate not
exceeding 0,1 octaves per second, over the range of 150 Hz to 6 000 Hz, the level of signal
recovered from the VDR shall not vary by more than a total range of 6 dB, on playback. Any
other microphone input ports shall have no signals applied at this time.
5.6.4 Quality index
The quality of the recording shall be established for single and multiple microphone inputs.
5.6.4.1 Single microphone
The quality of the recording for each of the bridge area microphone ports shall be established
at the electrical equivalent level of 75 dBA. This shall be not less than that corresponding to the
quality value for the speech transmission index of 0,85 (see IEC 60268-16), with no signal
being simultaneously applied to other microphone ports.
5.6.4.2 Multiple microphones
The quality of the recording for each of the bridge area microphone ports shall be established
at the electrical equivalent level of 75 dBA. This shall be not less than that corresponding to the
quality value for the speech transmission index of 0,60 (see IEC 60268-16) with all of the other
microphone ports having inputs at the electrically equivalent level of 65 dBA.
5.6.4.3 Audio noise level – signal-to-no signal

With no signal applied to any bridge area microphone port, the reproduced signal at any replay
output shall be at least 48 dB below the output level, which would be produced by an input level
equal to the reference signal level. This requirement shall be met across the frequency band as
defined in 5.6.3 with the inputs both open- and short-circuited. The above signal to no signal
performance shall be met in the presence of out-of-band input signals and also at the reference
signal level.
5.6.5 Audio noise level – signal-to-noise and distortion
With all other input ports, except the one in use, short-circuited, the reproduced signal to noise
and distortion (SINAD) ratio shall be at least 24 dB across the frequency band as defined
in 5.6.3 and with input levels in the range of 0 dB to –20 dB relative to the reference signal
level for all input ports.
– 16 – 61996 © IEC:2000(E)
5.7 Communications audio
5.7.1 Input interfaces
The audio connection with the designated VHF equipment shall be in accordance with the
requirements of IEC 61097-7. For the purpose of testing, the connection shall be via a
plug/socket combination referred to hereinafter as the input port.

5.7.2 Reference signal
The reference signal level for both transmitted and received communications audio is defined

as 0,775 V r.m.s.
5.7.3 Audio frequency response
With a signal level 6 dB below the reference signal level applied to the VHF radio
communications input port of the VDR and with its frequency continuously swept at a rate not
exceeding 0,1 octaves per second over the range of 150 Hz to 3 500 Hz, the level of the signal
recovered from the VDR on playback shall not vary by m
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