SIST EN 4856:2023

SLOVENSKI STANDARD
01-april-2023
Aeronavtika - Rotoplani - Sistem prezračevanja v sili (EBS) - Zahteve, preskušanje
in označevanje
Aerospace series - Rotorcraft - Emergency Breathing Systems (EBS) - Requirements,
testing and marking
Luft-und Raumfahrt - Drehflügler - Notfallbeatmungssystem (EBS) - Anforderungen,
Prüfung und Kennzeichnung
Série aérospatiale - Giravion - Système de ventilation d'urgence (EBS) - Exigences,
essais et marquage
Ta slovenski standard je istoveten z: EN 4856:2023
ICS:
49.095 Oprema za potnike in Passenger and cabin
oprema kabin equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 4856
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2023
EUROPÄISCHE NORM
ICS 49.095 Supersedes EN 4856:2018
English Version
Aerospace series - Rotorcraft Emergency Breathing
Systems (EBS) - Requirements, testing and marking
Série aérospatiale - Systèmes de ventilation d'urgence Luft-und Raumfahrt - Drehflügler
(EBS) de giravion - Exigences, essais et marquage Notfallbeatmungssystem (EBS) - Anforderungen,
Prüfung und Kennzeichnung
This European Standard was approved by CEN on 18 December 2022.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 4856:2023 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 7
4 Design types . 11
4.1 Compressed air EBS . 11
4.2 Hybrid rebreather EBS . 11
5 Performance requirements . 11
5.1 General. 11
5.2 Design . 12
5.3 Materials . 13
5.4 Breathing performance . 13
5.4.1 General. 13
5.4.2 Work of breathing . 14
5.4.3 Respiratory pressures. 14
5.4.4 Hydrostatic imbalance . 14
5.4.5 Extreme cold water temperatures . 14
5.5 Safety devices . 14
5.6 Deployment . 15
5.7 Ease of use and manoeuvrability in water . 15
5.8 Buoyancy . 15
5.9 Cold water performance . 16
5.10 Compatibility . 16
5.10.1 General. 16
5.10.2 Performance of equipment combination(s) . 16
6 Testing . 19
6.1 Visual inspection . 19
6.2 Nominal values and tolerances . 19
6.3 Magnetic properties testing . 19
6.4 Temperature cycling. 19
6.5 Breathing performance . 20
6.6 Breathable volume of counterlung . 22
6.7 Buoyancy. 23
6.8 Ergonomic performance . 23
6.8.1 General . 23
6.8.2 Test subjects . 24
6.8.3 Deployment. 26
6.8.4 Ease of use, manoeuvrability and helicopter escape . 26
6.9 Cold water performance . 28
6.10 Compatibility and performance of equipment combination(s) . 28
6.10.1 General . 28
6.10.2 Test subjects . 28
6.10.3 Clothing . 28
6.10.4 Compatibility and equipment combination performance testing . 29
6.10.5 Donning and fit . 29
6.10.6 Ride-up . 29
6.10.7 Helicopter underwater escape . 30
6.10.8 Jump into water . 30
6.10.9 Freeboard . 31
6.10.10 Turning . 31
6.10.11 Self-righting . 31
6.10.12 In-water stability . 32
6.10.13 Freedom of movement and use of accessories . 32
6.10.14 Life raft boarding . 33
6.10.15 Rescue and recovery . 33
6.10.16 Escape buoyancy . 33
6.11 Crew equipment compatibility . 34
6.12 Reporting . 36
7 Marking . 36
8 Information supplied by the manufacturer . 37
Annex A (normative) Rating of breathing effort . 38
A.1 Instruction . 38
Annex B (informative) Evolution sheet. 39
Bibliography . 40

European foreword
This document (EN 4856:2023) has been prepared by the Aerospace and Defence Industries
Association of Europe - Standardization (ASD-STAN).
After enquiries and votes carried out in accordance with the rules of this Association, this document has
received the approval of the National Associations and the Official Services of the member countries of
ASD-STAN, prior to its presentation to CEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by August 2023, and conflicting national standards shall
be withdrawn at the latest by August 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 4856:2018.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Introduction
This document prescribes the minimum standards of design and performance for rotorcraft emergency
breathing systems (EBS), used to reduce the risks of drowning in the event of submersion. An EBS is a
form of personal protective equipment that provides the user with a means to breathe underwater,
thereby improving the probability of successfully escaping from a submerged rotorcraft cabin. If used
correctly, EBS should mitigate the risk of drowning.
This document aims to ensure that the equipment user is able to carry out the necessary emergency
procedures whilst being provided with an appropriate level of protection under foreseeable conditions
of use. It also aims to ensure that the equipment presents a minimal hazard in relation to escape from
the rotorcraft, and that the equipment has no detrimental effect on the health and safety of the user or
on the performance of other equipment.
This document is applicable to all rotorcraft. Rotorcraft include helicopters, tilt rotor/wing and
gyroplanes. For the purpose of this document the term helicopter is used generically hereinafter.
1 Scope
This document specifies requirements for Emergency Breathing Systems (EBS) for use by helicopter
crew and passengers in the event of a ditching or water impact, to ensure minimum levels of
performance. It applies to EBS capable of being successfully and reliably deployed in air and
underwater, for use by adults only.
This document is applicable to compressed air and hybrid rebreather designs of EBS. It does not apply
to EBS that cannot be successfully and reliably deployed underwater.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 250, Respiratory equipment — Open-circuit self-contained compressed air diving apparatus —
Requirements, testing and marking
EN 4862, Aerospace series — Rotorcraft constant wear lifejackets — Requirements, testing and marking
1 2
EN 4863:— , Aerospace series — Rotorcraft immersion suits — Requirements, testing and marking
EN 4886, Aerospace series — Rotorcraft life rafts — Requirements, testing and marking
EN 12021, Respiratory equipment — Compressed gases for breathing apparatus
EN 14143:2013, Respiratory equipment — Self-contained re-breathing diving apparatus
EN ISO 9227, Corrosion tests in artificial atmospheres — Salt spray tests (ISO 9227)
EN ISO 12894, Ergonomics of the thermal environment — Medical supervision of individuals exposed to
extreme hot or cold environments (ISO 12894)
EN ISO 14116:2015, Protective clothing — Protection against flame — Limited flame spread materials,
material assemblies and clothing (ISO 14116:2015)
EN ISO 15025:2016, Protective clothing — Protection against flame — Method of test for limited flame
spread (ISO 15025:2016)
EASA CS-25 Amendment 26:2020, Certification Specifications and Acceptable Means of Compliance for
Large Aeroplanes CS-25, Book 1 — Appendix F

Under preparation. Current stage is: FprEN 4862:2022.
Under preparation. Current stage is: ASD-STAN prEN 4863:2022.
In preparation at the date of publication of this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
emergency breathing system
EBS
system that allows a person to breathe underwater, overcoming the need to breath-hold for the
complete duration of an underwater escape from a helicopter, that can be deployed under emergency
conditions
3.2
lifejacket
garment or device which, when correctly worn and used in water will provide the user with buoyancy
positioned to provide protection from drowning and increase the likelihood of survival and rescue
3.3
helicopter constant wear lifejacket
lifejacket worn on the body throughout a helicopter flight, provided to protect the user in the event of a
ditching or water impact
3.4
immersion suit
garment designed to protect the user’s body from the cooling effects of unintended immersion in water
Note 1 to entry: Cooling effects include cold shock and hypothermia.
Note 2 to entry: An immersion suit may be integrated or worn with a separate constant wear lifejacket.
3.5
integrated immersion suit
immersion suit that incorporates the functionality of a lifejacket
3.6
buoyancy element
inflatable chamber incorporated into an integrated immersion suit that, when inflated, provides the suit
with the functionality of a lifejacket
3.7
helicopter immersion suit
immersion suit worn on the body throughout a helicopter flight, provided to protect the user in the
event of a ditching or water impact
3.8
immersion suit system
helicopter immersion suit (with or without thermal insulation) and its components and accessories
including a constant wear lifejacket or buoyancy element and its components and accessories with or
without an emergency breathing system
3.9
fully inflated
inflation of a lifejacket or buoyancy element achieved by using the manual inflation system (stored gas)
with no subsequent deflation
3.10
manual inflation system
means of inflation achieved by a person operating a mechanism that actively releases stored gas into
the buoyancy chamber(s) of a lifejacket or buoyancy element
3.11
oral inflation system
means of inflation achieved by a person blowing expired air into the buoyancy chamber(s) of a
lifejacket or buoyancy element
3.12
rotorcraft
heavier-than-air aircraft that depends principally for its support in flight on the lift generated by one or
more rotors
3.13
helicopter
rotorcraft that, for its horizontal motion, depends principally on its engine-driven rotors
3.14
ditching
controlled emergency landing on water, deliberately executed in accordance with Rotorcraft Flight
Manual procedures, with the intent of abandoning the rotorcraft as soon as practical
3.15
water impact
helicopter contact with water that is unintentional or exceeds the ditching capability of the helicopter
for water entry
3.16
crew member
person assigned by an operator to perform duties on board an aircraft
3.17
mouthpiece
device that goes into the mouth of the user, usually held by the teeth, sealing against the lips and
through which a breathable gas is inhaled and exhaled
3.18
nose occlusion system
means of preventing water from entering the nose
Note 1 to entry: A nose clip is one example of a nose occlusion system.
3.19
demand regulator
device which consists of a pressure reducer connected to a demand valve
3.20
medium pressure hose
hose with an interface connection at each end, between the pressure reducer and a demand valve
3.21
breathing hose
flexible hose connecting a counterlung to the mouthpiece of a hybrid rebreather EBS, at approximately
ambient pressure
3.22
pressure indicator
device to indicate to the user the pressure of gas in a cylinder
3.23
purging device
part of the demand regulator that can be operated manually to deliver breathable gas, intended to force
water out of the mouthpiece
3.24
dead space
volume of the cavity formed between the mouth and the inhalation and exhalation parts
3.25
activation device
mechanism which switches breathing from the atmosphere to the counterlung of a hybrid rebreather
EBS
3.26
counterlung
variable volume container for the user to exhale to and inhale from
3.27
breathable gas
gas that will support life under the intended conditions of use
3.28
work of breathing
work expended during one breathing cycle which is proportional to the area bounded by the pressure
volume diagram divided by the tidal volume
Note 1 to entry: Measured in J/l.
3.29
respiratory pressure
differential pressure at the mouth relative to the no flow pressures measured at the end of inhalation
and exhalation
3.30
hydrostatic imbalance
difference at end exhalation no flow between the pressure at the mouth and that at the lung centroid
reference point
3.31
tidal volume
volume of breathing gas displaced by the breathing simulator during one half cycle (inhalation or
exhalation)
Note 1 to entry: Measured in l.
3.32
respiratory minute volume
product of the tidal volume and breathing frequency
Note 1 to entry: Measured in l/min.
3.33
useable volume of air
volume of breathable air available to the user while the demand regulator is operating within the
specified breathing performance
3.34
rated working pressure
maximum working pressure of the respective components
3.35
pressure volume diagram
diagram generated during one breathing cycle by plotting the respiratory pressure against the
displaced (tidal) volume
3.36
elastance
change in pressure that results from a given volume change of the human lung
Note 1 to entry: Measured in kPa/l.
Note 2 to entry: This is a typical term for the elastic behaviour of a breathing system.
3.37
reference pressure
equilibrium pressure which exists in the mouthpiece when there is no respiratory flow at the end of
exhalation
3.38
escape buoyancy
buoyancy of an equipment combination, with the lifejacket or buoyancy element uninflated, that must
be overcome when escaping from an immersed helicopter
Note 1 to entry: It includes the inherent buoyancy of the components of the immersion suit system and entrapped
air but excludes the inflated buoyancy elements.
4 Design types
4.1 Compressed air EBS
A compressed air EBS is a system where air or some other breathable gas is supplied to the user on
demand from a high pressure gas cylinder, the period of breathing being limited by the volume of
useable gas.
The apparatus shall comprise at least the following components:
— mouthpiece;
— medium pressure hose;
— gas cylinder;
— demand regulator;
— pressure indicator;
— purging device;
— nose occlusion system.
4.2 Hybrid rebreather EBS
A rebreather EBS is a system with a counterlung which allows the user to move air out of and back into
their lungs, the period of rebreathing being limited by a build-up of carbon dioxide and a reduction in
oxygen concentration. A hybrid rebreather EBS is a rebreather system that incorporates a compressed
gas cylinder, allowing a small volume of air or other breathable gas to be introduced into the
counterlung, the period of rebreathing being limited by a build-up of carbon dioxide and a reduction in
oxygen concentration.
The system shall comprise at least the following components:
— mouthpiece;
— breathing hose;
— counterlung;
— gas cylinder with gas release system;
— activation device;
— nose occlusion system.
5 Performance requirements
5.1 General
5.1.1 EBS covered by this document shall be capable of being rapidly deployed and used both in air
and underwater. They shall be suitable for use when capsize and/or sinking occurs immediately after
the helicopter makes contact with the water.
5.1.2 Where applicable, EBS shall be tested in combination with associated equipment, including an
immersion suit, accessories and/or lifejacket that is intended to be worn with it, in accordance with 6.8.
It shall be deployed in the same manner as it would be in normal service, and from the intended stowed
position (6.1 and 6.8.3).
NOTE Helicopter immersion suits are hereinafter referred to as immersion suits. Helicopter constant wear
lifejackets are hereinafter referred to as lifejackets.
5.1.3 If a compressed breathable gas other than air is used, additional assessment and testing might
be required. This shall be determined following visual inspection in accordance with 6.1.
5.2 Design
5.2.1 The EBS shall be practicable in use and light in weight without prejudice to the design strength
and performance. Testing shall be carried out in accordance with 6.1 and 6.8.
5.2.2 The EBS shall be simple to deploy and capable of being operated with either hand. The number
of deployment actions shall be minimized; for example, no more than one action should be required to
activate a hybrid rebreather system on submersion, i.e. opening the valve of the counterlung. Testing
shall be carried out in accordance with 6.1, 6.8.3 and 6.8.4.
5.2.3 The equipment shall not have any sharp edges or protruding parts which might injure the user,
or damage the lifejacket, immersion suit system or other emergency equipment. Testing shall be carried
out in accordance with 6.1 and 6.8.
5.2.4 Compressed air EBS shall provide the user with a minimum useable volume of air of 50 l
Standard Temperature and Pressure Dry (STPD), meeting the requirements of EN 12021. Testing shall
be carried out in accordance with 6.1 and 6.5.
5.2.5 Where a counterlung is incorporated into a hybrid rebreather system, the counterlung shall
have sufficient breathable capacity to accommodate an expired volume of at least 6 l (STPD). Additional
capacity shall be provided equivalent to the volume of breathable gas discharged into the counterlung
from the gas cylinder. The gas cylinder shall provide a minimum useable volume of air of at least 3 l
STPD, meeting the requirements of EN 12021. The counterlung shall be designed to prevent collapse,
taking panic breathing into account. Testing shall be carried out in accordance with 6.1, 6.5.2 and 6.6.
5.2.6 The EBS design shall minimize the amount of water that can enter the mouthpiece (dead space).
It shall be possible to expel this water from the mouthpiece. Testing shall be carried out in accordance
with to 6.1, 6.8.3.2, 6.8.4.4, 6.8.4.5 and 6.8.4.6.
5.2.7 Subjects shall be provided with a means to prevent water entering the nose that is easy to
deploy and effective when used underwater. Nose occlusion systems (including nose clips) shall be
designed to fit a wide range of user sizes. Nose clips shall be easy to open with either hand and shall be
permanently attached to the EBS, on or adjacent to the mouthpiece. Testing shall be carried out in
accordance with 6.1 and 6.8.
5.2.8 Where an EBS includes a harness to fit the EBS to the body, this shall allow correct positioning
on the body when used according to the manufacturer's instructions. Testing shall be carried out in
accordance with 6.1 and 6.8.
5.2.9 Gas cylinders and connections with demand regulators shall comply with the appropriate
European specifications and shall be approved and tested with respect to the rated working pressure
and for underwater use. Testing shall be carried out in accordance with 6.1.
NOTE Some composite cylinders are not approved for underwater use.
5.2.10 Leakage from compressed air EBS shall not exceed 10 % of the initial cylinder pressure, in any
single case, when tested in accordance with 6.5.6.
5.3 Materials
5.3.1 The materials used shall have adequate mechanical strength to resist damage. Testing shall be
carried out in accordance with 6.1, 6.5, 6.8.3, 6.8.4, 6.9, 6.10 and 6.11.
5.3.2 The materials used shall have sufficient resistance to changes caused by the effects of
temperature. There shall be no signs of degradation to the materials and the EBS shall remain
functional following temperature cycling, when tested in accordance with 6.4.
5.3.3 Any fabric integral to the EBS and not part of a lifejacket or suit system, used to cover, retain or
secure the EBS on the user shall be of low flammability.
Fabrics used to cover, retain or secure the EBS on the user shall as a minimum meet the horizontal test
of EASA CS-25 Appendix F Part 1 (a)(1)(iv) (or as amended).
The cover fabric shall as a minimum meet flame spread Index 3 of EN ISO 14116:2015, when tested in
accordance with EN ISO 15025:2016, method A. The test shall be performed on three samples in the
warp direction and three samples in the weft direction, after a pre-treatment of five cleaning cycles in
accordance with the manufacturer's cleaning instructions.
5.3.4 All metallic components shall be made of corrosion-resistant materials or be protected from
corrosion. Metallic components shall not be significantly affected by corrosion when tested in
accordance with the neutral salt spray (NSS) test of EN ISO 9227 for a period of 160 h. After the test, the
components shall still operate as designed.
The EBS shall not affect a magnetic compass by more than 1° when placed 300 mm from the compass.
Testing shall be carried out in accordance with 6.3.
5.3.5 Any high or medium pressure parts and connections shall meet the requirements of EN 250.
5.3.6 All parts that have to be cleaned and/or disinfected shall be easy to clean, be insensitive to the
cleaning agents and disinfectants recommended by the manufacturer and remain functional after
having been cleaned or disinfected. Recommended cleaning or disinfectant products shall not be known
to have any adverse effect on the user. Testing shall be carried out in accordance with 6.1.
5.4 Breathing performance
5.4.1 General
The work of breathing, respiratory pressures, hydrostatic imbalance and extreme cold water
requirements specified in 5.4.2 to 5.4.5 shall be met under the following conditions:
— simulated breathing using a sinusoidal waveform, with respiratory minute volumes as shown in
Table 1;
— in water at a temperature of ( 4 ) °C, and extreme cold water (5.4.5) if specified by the
−2
manufacturer;
— simulated orientations of vertical (pitch +90°), inverted (pitch −90°) and face-down (pitch 0°) with
zero roll.
NOTE Pitch and roll definitions are as described in EN 14143.
When tested in accordance with 6.5, dynamic performance shall be determined from a pressure volume
diagram (see Figure 1 and Figure 2) generated by plotting pressure against displaced volume.
5.4.2 Work of breathing
Work of breathing shall not exceed 3,0 J/l at ventilation rates up to and including 62,5 l/min ATP. The
EBS shall remain functional at ventilation rates up to 75 l/min ATP. Testing shall be carried out in
accordance with 6.5.1, 6.5.2, 6.5.3 and 6.5.4.
5.4.3 Respiratory pressures
Peak-to-peak respiratory pressure shall be determined as shown in Figure 1 (compressed air EBS) or
Figure 2 (hybrid rebreather EBS), expressed as b, and shall not exceed 5,0 kPa (50 mbar).
For compressed air EBS, peak expired respiratory pressure, expressed as c in Figure 1, shall not exceed
2,5 kPa (25 mbar) and peak inspired respiratory pressure, expressed as d in Figure 1, shall not exceed
2,5 kPa (25 mbar).
For hybrid rebreather EBS, the elastance of the system, determined as shown in Figure 2 and expressed
by c/a, shall not exceed 1 kPa/l (10 mbar/l).
For compressed air EBS the demand regulator shall not free-flow during testing.
Testing shall be carried out in accordance with 6.5.1, 6.5.2, 6.5.3 and 6.5.4.
5.4.4 Hydrostatic imbalance
For hybrid rebreather EBS, hydrostatic imbalance shall be between +2,5 kPa (+25 mbar) and
−2,5 kPa (−25 mbar) relative to lung centroid pressure. Testing shall be carried out in accordance with
6.5.5.
5.4.5 Extreme cold water temperatures
If the EBS is intended for use in water temperatures less than 4 °C the manufacturer shall state the
minimum operational temperature. The breathing performance of the EBS shall also be tested and meet
the requirements of 5.4.2 to 5.4.4 at the surface (immersed to a depth sufficient to preclude surface
effects), at that temperature. Testing shall be carried out in accordance with 6.5.
5.5 Safety devices
5.5.1 For a compressed air EBS, a pressure indicator shall be provided to confirm that there is
adequate gas in the cylinder. An indicator shall be provided to show that the system is ready for use.
Testing shall be carried out in accordance with 6.1.
5.5.2 For hybrid rebreather EBS, the gas cylinder shall have a status indicator to show that the gas
release system is in a ready to use condition. Testing shall be carried out in accordance with 6.1.
5.5.3 For hybrid rebreather EBS, it shall be possible to check that the EBS is ready for use and has not
been tampered with. Testing shall be carried out in accordance with 6.1.
5.5.4 Where a security tag or anti-tamper stitching is used, this shall be a weak link that is easy to
break during emergency deployment. Testing shall be carried out in accordance with 6.1 and 6.8.3.1.
5.5.5 The risk of inadvertent operation or activation by the user shall be minimized, including the
inadvertent release of gas from a cylinder. Testing shall be carried out in accordance with 6.1, 6.8
and 6.10.
5.6 Deployment
5.6.1 With the EBS configured for flight, in accordance with the manufacturer's instructions, it shall
be possible to fully deploy the EBS in less than 12 s, using one hand only (this time shall include
deployment of the nose occlusion system). This shall be achievable with both the right hand and the left
hand. It shall be possible to deploy the mouthpiece within 10 s (this time may exclude deployment of
the nose occlusion system). Testing shall be conducted in dry conditions, in accordance with 6.8.3.1.
5.6.2 It shall be demonstrated that full deployment can be achieved, with each hand, following
submersion. Test subjects shall be able to clear water from the mouthpiece if necessary, achieve a good
seal at the mouth and breathe from the EBS. Testing shall be carried out in accordance with 6.8.3.2.
It shall be possible to deploy the EBS when inverted underwater following a 180° sideways roll. Testing
shall be carried out in accordance with 6.8.4.4.
5.7 Ease of use and manoeuvrability in water
5.7.1 Test subjects shall be able to achieve a good seal at the mouth, whilst manoeuvring underwater
in different orientations including the face-down (prone) position. This shall be tested in accordance
with 6.8.4.1.
5.7.2 Each test subject shall demonstrate their ability to use the EBS for at least 60 s whilst pulling
themselves along an underwater rail in the face-down position. This shall be tested in accordance
with 6.8.4.2.
5.7.3 Each test subject shall demonstrate their ability to use the EBS for at least 60 s whilst inverted.
This shall be tested in accordance with 6.8.4.3 and 6.8.4.4.
5.7.4 Each test subject shall demonstrate their ability to use the EBS whilst successfully completing
underwater escape from a submerged and capsized helicopter simulator. No part of the EBS shall snag
or unduly hinder egress. The system shall not cause injury to the user nor impair the performance of
other equipment. This shall be tested in accordance with 6.8.4.5 and 6.8.4.7.
5.7.5 Each test subject shall demonstrate their ability to escape from a submerged and capsized
helicopter simulator when the EBS is not deployed. No part of the EBS shall snag or unduly hinder
egress. The system shall not cause injury to the user nor impair the performance of other equipment.
This shall be tested in accordance with 6.8.4.5 and 6.8.4.7.
5.8 Buoyancy
The buoyancy of a hybrid rebreather EBS shall be no more than 40 N following release of gas from the
cylinder. This shall be tested in accordance with 6.7. This test is not required for open circuit
compressed air systems.
5.9 Cold water performance
Each test subject shall demonstrate their ability to use the EBS in cold (12 °C) water for at least 60 s.
Testing shall be carried out in accordance with 6.9.
5.10 Compatibility
5.10.1 General
5.10.1.1 The EBS shall be designed, and the materials used in its construction chosen, to have no
features which would be likely to have any detrimental effect on the operation of any helicopter or its
equipment. Testing shall be carried out in accordance with 6.11.
5.10.1.2 Potential snagging hazards shall be reduced to a minimum. Any part of the EBS that might
pose a snagging hazard during flight, emergency evacuation, escape, rescue or recovery shall be suitably
covered, protected or restrained. Testing shall be carried out in accordance with 6.1, 6.8 and 6.10.
5.10.1.3 EBS intended for use by crew members shall be designed such that, when stowed, the crew
member shall be able to carry out all normal and emergency procedures, without undue impediment or
discomfort. Testing shall be carried out in accordance with 6.11.
5.10.1.4 The EBS shall not impair the performance of a seat harness or hinder harness fitting and
release. Testing shall be carried out in accordance with 6.8.3, 6.8.4, 6.10 and 6.11.
5.10.1.5 Approval of each EBS to this document shall take into account the compatibility between the
EBS and any other equipment (e.g. lifejacket, immersion suit and associated accessories) that is
intended to be worn with it. Each EBS shall be tested in accordance with 6.10 and 6.11 as applicable.
If the EBS is intended to be used with more than one equipment combination that could impair
performance, the testing of 6.10 and 6.11, as applicable, shall be repeated with each additional
equipment combination.
5.10.2 Performance of equipment combination(s)
5.10.2.1 General
The requirements for combined EBS, lifejacket and immersion suit performance shall apply to all
immersion suit systems, to immersion suits worn with a separate lifejacket and to integrated
immersion suits, unless stated otherwise.
Immersion suit system performance requirements shall also apply to different combinations of EBS,
immersion suit, accessories and/or lifejackets.
5.10.2.2 Donning and fit
When the EBS is worn in combination with an immersion suit and/or lifejacket, it shall be possible to
don the complete equipment combination and achieve a secure fit. Testing shall be carried out in
accordance with 6.1 and 6.10.
5.10.2.3 Ride-up
The lifejacket or buoyancy element of an integrated immersion suit shall not ride up to such an extent
as to impair the performance of the immersion suit system. When the immersion suit is worn in
combination with a separate lifejacket and EBS, the user shall not slip out of the lifejacket. Testing shall
be carried out in accordance with 6.10, with special reference to 6.10.6 and 6.10.8.
5.10.2.4 Helicopter escape
When the EBS is worn in combination with an immersion suit and/or lifejacket, with the lifejacket or
buoyancy element of an integrated immersion suit uninflated, the equipment combination shall not
impede or prevent evacuation or escape from a helicopter. This action shall be possible above water
and underwater from a submerged helicopter simulator.
Each test subject shall demonstrate their ability to escape successfully from the submerged helicopter
simulator, through an emergency exit as defined in 6.8.1.6. No part of the EBS, immersion suit and/or
lifejacket combination shall snag or unduly hinder egress. Testing shall be carried out in accordance
with 6.10.7.
5.10.2.5 Jump into water
Following a jump from 4,5 m wearing the EBS in combination with an immersion suit and/or lifejacket,
with the lifejacket or buoyancy element of an integrated immersion suit uninflated, the test subject shall
not be injured and the equipment under test shall not be damaged when tested in accordance with
6.10.8. After inflation of the lifejacket or buoyancy element, the freeboard shall meet the requirements
defined in 5.10.2.6, when tested in accordance with 6.10.9.
Following a jump from 1 m when wearing the EBS in combination with an immersion suit and/or
lifejacket, with lifejacket or buoyancy element of an integrated immersion suit fully inflated, the
freeboard shall meet the requirements defined in 5.10.2.6 and the nose freeboard shall not be less than
the mouth freeboard, when tested in accordance with 6.10.9.
The lifejacket or buoyancy element of an integrated suit shall not ride-up. The user shall not slip out of a
lifejacket. Testing shall be carried out in accordance with 6.10.6 and 6.10.8.
5.10.2.6 Freeboard
When the EBS is worn in combination with an immersion suit and/or lifejacket, with the lifejacket or
buoyancy element of an integrated immersion suit fully inflated, the equipment combination shall
achieve a floating position and provide lateral and occipital support of the user’s head such that the
mouth is
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