FprEN 4709-008
(Main)Aerospace series - Unmanned Aircraft Systems - Part 008: C5 Accessories kits
- Status
- Not Published
- Publication Date
- 31-Jan-2027
- Technical Committee
- CEN/TC 471 - Aviation and aeronautics
- Drafting Committee
- CEN/TC 471/WG 1 - Unmanned Aircraft Systems
- Current Stage
- 4599 - Dispatch of FV draft to CMC - Finalization for Vote
- Start Date
- 31-Jul-2026
- Completion Date
- 31-Jul-2026
FprEN 4709-008 is a CEN draft European standard in the aerospace series for Unmanned Aircraft Systems (UAS). It specifies technical requirements and verification methods for C5 accessories kits that convert a class C3 unmanned aircraft (UA) into a class C5 UA, and it is intended for kit providers, UAS manufacturers, and qualified kit integrators who need to show product compliance and prepare the related instructions and test evidence.
What does FprEN 4709-008 specify?
FprEN 4709-008 specifies how a C5 accessories kit is to be designed, identified, installed, and verified so that it can be fitted to a class C3 UAS without changing the UAS’s original C3 compliance. It also sets out the documents and checks needed to show that the fitted system meets the extra C5 class requirements.
The scope is narrow and practical. FprEN 4709-008 applies to rotary-wing UA with electro-chemical energy sources, and it excludes fixed-wing, VTOL, and other hybrid UA. Security and IT security are outside the scope, and payload-related hazards remain the responsibility of the UAS manufacturer and operator.
The document is organized around:
- Clause 1 on scope
- Clause 2 on normative references
- Clause 3 on terms and definitions
- Clause 4 on product requirements and compliance
- Annexes A to D and Annex ZA
| Annex | What it covers |
|---|---|
| Annex A | Example procedure for testing accessories kit functions |
| Annex B | Functionalities added to convert C3 UA to C5 class |
| Annex C | Accessories kit elements and an integration example |
| Annex D | Example structure of the accessory kit manual |
| Annex ZA | Relationship with the essential requirements of Delegated Regulation (EU) 2019/945 as amended |
What are the key requirements of FprEN 4709-008?
FprEN 4709-008 focuses on compatibility, preservation of the original C3 configuration, and evidence that the kit still supports safe operation after installation. Clause 4 is the main technical core, and each requirement is paired with a verification method and pass criteria.
Compatibility is limited to class C3 rotary-wing UAS
Clause 4.1 says the accessories kit may only convert a class C3 UAS, and the compatible UAS must not be fixed-wing. The kit provider has to identify compatible UAS models, their versions, and, where relevant, compatible configurations and software versions. In practice, this means the buyer or integrator must check the exact aircraft variant before fitting the kit.
The kit must not alter the original software
Clause 4.2 requires the kit not to change the original software of the class C3 UAS. Software configuration instructions are allowed, but the kit functions must remain independent from the drone software, and the applicable software versions must be listed. This matters because compatibility depends on the original flight system remaining intact.
The fitted UAS must still meet the original C3 limits
Clause 4.3 requires the kit not to alter the original C3 compliance. The fitted UAS must stay within the C3 MTOM, remain under the maximum characteristic dimension limit, stay safely controllable, and comply with tether, power, data link protection, and conspicuity lighting conditions where they apply. In practice, this is the main check that the added equipment does not make the aircraft larger, heavier, or less controllable than allowed.
The accessories themselves must be identified and labelled
Clause 4.4 requires each accessory to be identified and marked with the C5 label. The technical documentation must include a bill of materials, part numbers, software versions where relevant, quantity, drawings or identification means, descriptions, and functional verification checks. This helps users match the physical parts to the approved kit and prevents mixing in unlisted components.
Installation and removal must be documented
Clause 4.5 requires an installation procedure, description of any special tools, and information on the skills needed for installation. The document also expects a means to record installation, upgrades, and modifications. Clause 4.7 adds operating, maintenance, and unmounting instructions, including the tools, skills, and frequency of maintenance tasks. For a buyer or quality manager, this is the part that supports service, training, and recordkeeping.
The installed kit must provide the extra C5 functions
Clause 4.6 requires the fitted UAS to support the C5-related functions, except for providing the remote pilot with clear and concise height information. The kit must provide a selectable low-speed mode limited to 5 m/s, monitoring and alerting for the C2 link and the kit link, and a description of the means to terminate flight, including the distance travelled after activation. In practice, these are the safety functions that must still work after conversion.
Verification methods are tied to other parts of the series
Clause 4 repeatedly points to methods and pass criteria in the related prEN 4709 parts. This means the standard is meant to be used as a compliance package, not as a standalone design guide.
What terms does FprEN 4709-008 define?
CE marking is the marking by which the manufacturer indicates conformity with the applicable Union harmonization requirements.
kit provider is the legal entity that provides the C5 accessory kit and its accompanying requisites under its name or trademark.
qualified kit integrator is the legal or natural person with suitable expertise and knowledge to install and verify the kit.
means to reduce the effect of the UA impact dynamics is a technical means that prevents major impact damage so the remote pilot is not discouraged from activating the flight-termination function.
payload means equipment or an accessory installed in or attached to the aircraft that is not used to operate or control it in flight and is not part of the airframe, engine, or propeller.
UA means an aircraft designed to operate autonomously or be piloted remotely without a pilot on board.
UAS software modification means a software change not documented by the original UA manufacturer in its instructions.
Who uses FprEN 4709-008?
FprEN 4709-008 is used by C5 accessories kit manufacturers, C3 UAS manufacturers, conformity assessment teams, quality managers, buyers, installers, and operators. It helps them decide whether a kit is compatible with a given aircraft, how to install and label it, what records to keep, and what test evidence to prepare for compliance work and CE-marking-related documentation.
Which standards are used with FprEN 4709-008?
- prEN 4709-001:2021 - provides product requirements and verification methods used for compatibility, MTOM, characteristic dimension, controllability, tethering, power, and data link protection checks.
- prEN 4709-004:2020 - provides the lighting requirement method used for conspicuity lighting checks.
- prEN 4709-006:2023 - provides the requirements and verification for means to terminate flight, including related kit testing.
- prEN 4709-007:2024 - provides general product requirements for UAS of classes C5 and C6, including C2 link monitoring and alerting.
- EN 61310-1 - is referenced in notes as guidance for aural, visual, and haptic signals.
What does the FprEN 4709-008 document contain?
FprEN 4709-008 contains clause-by-clause requirements, verification methods, and pass criteria, plus informative annexes with examples and supporting structures. Annex A gives example tests for FTS, parachute systems, and other impact-energy reduction means. Annex B lists the functions needed to convert a C3 UA to C5 class, including FTS and impact-dynamics reduction options such as parachute recovery and stabilized descent modes. Annex C shows kit elements and an integration example, and Annex D gives an example manual structure covering compatibility, components, testing, installation, instructions, and operation recording. Annex ZA links the document to the essential requirements of Delegated Regulation (EU) 2019/945 as amended by (EU) 2020/1058.
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Frequently Asked Questions
FprEN 4709-008 is a draft published by the European Committee for Standardization (CEN). Its full title is "Aerospace series - Unmanned Aircraft Systems - Part 008: C5 Accessories kits". This standard covers: Aerospace series - Unmanned Aircraft Systems - Part 008: C5 Accessories kits
Aerospace series - Unmanned Aircraft Systems - Part 008: C5 Accessories kits
FprEN 4709-008 is classified under the following ICS (International Classification for Standards) categories: 49.020 - Aircraft and space vehicles in general. The ICS classification helps identify the subject area and facilitates finding related standards.
FprEN 4709-008 is associated with the following European legislation: EU Directives/Regulations: 2019/945; Standardization Mandates: M/567. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
FprEN 4709-008 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-maj-2024
Aeronavtika - Letalski sistemi brez posadke - 008. del: C5 Dodatni kompleti
Aerospace series - Unmanned Aircraft Systems - Part 008: C5 Accessories kits
Luft- und Raumfahrt - Unbemannte Luftfahrzeugsysteme - Teil 008: Zubehörsätze der
Klasse C5
Série aérospatiale - Aéronefs télépilotés - Partie 008 : Kits d'accessoires classe C5
Ta slovenski standard je istoveten z: prEN 4709-008
ICS:
49.020 Letala in vesoljska vozila na Aircraft and space vehicles in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
EUROPEAN STANDARD
prEN 4709-008
NORME EUROPÉENNE
EUROPÄISCHE NORM
February 2024
ICS
English Version
Aerospace series - Unmanned Aircraft Systems - Part 008:
C5 Accessories kits
Luft- und Raumfahrt - Unbemannte
Luftfahrzeugsysteme - Verifizierungsmethode für die
Geocaging Funktion.
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 471.
If this draft becomes a European Standard, 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.
This draft European Standard was established by CEN 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.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 4709-008:2024 E
worldwide for CEN national Members.
prEN 4709-008:2024 (E)
Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 6
4 Product requirements and compliance for accessories kit transforming a C3-class
UAS into a C5-class UAS . 7
4.1 UA configuration . 7
4.1.1 Requirements . 7
4.1.2 Verification method . 7
4.1.3 Pass criteria . 8
4.2 UAS software configuration . 8
4.2.1 Requirements . 8
4.2.2 Verification method . 8
4.2.3 Pass criteria . 8
4.3 UAS original C3 compliance . 8
4.3.1 General. 8
4.3.2 MTOM . 8
4.3.3 Maximum characteristic dimension . 9
4.3.4 Safely controllable . 9
4.3.5 Tethered UA . 10
4.3.6 Power . 10
4.3.7 Data link protection . 10
4.3.8 Conspicuity lightning . 11
4.4 Accessories list . 11
4.4.1 Requirements . 11
4.4.2 Verification method . 11
4.4.3 Pass criteria . 11
4.5 Accessories installation . 12
4.5.1 Requirements . 12
4.5.2 Verification methods . 12
4.5.3 Pass criteria . 12
4.6 Post-installation C5 compliance . 12
4.6.1 Low speed mode . 12
4.6.2 C2 link monitoring and alerting . 13
4.6.3 Accessory kit link monitoring and alerting . 14
4.6.4 Description of the means to terminate flight . 15
4.7 Kit instructions . 15
4.7.1 Requirements . 15
4.7.2 Verification methods . 15
4.7.3 Pass criteria . 16
Annex A (informative) Example procedure for testing the functionalities of the accessories
kit . 17
A.1 FTS functionality test . 17
prEN 4709-008:2024 (E)
A.2 Parachute system functionality test . 17
A.3 Other means to reduce the effects of impact dynamics functionality test . 17
Annex B (informative) Functionalities added to perform conversion of C3 UA to C5 class . 18
B.1 FTS (refer to prEN 4709-006:2023, Annex A) . 18
B.2 Means to reduce the effect of impact dynamics (refer to prEN 4709-006:2023,
Annex D) . 19
Annex C (informative) Accessories kits elements . 20
C.1 Accessories kit integration example . 20
C.2 Details of the parts . 21
Annex D (informative) Example of the structure of the accessory kit manual. 22
D.1 UA compatibility . 22
D.2 Kit components . 22
D.3 Kit testing . 23
D.4 Kit installation . 23
D.5 Kit instructions . 23
D.6 Operation recording . 24
Annex ZA (informative) Relationship between this document and the essential
requirements of Delegated regulation (EU) 2019/945 of 12th March 2019 amended
by (EU) 2020/1058 on unmanned aircraft systems and on third-country operators of
unmanned aircraft systems aimed to be covered . 26
Bibliography . 27
prEN 4709-008:2024 (E)
European foreword
This document (prEN 4709-008:2024) has been prepared by Technical Committee CEN/TC 471 UAS,
the secretariat of which is held by BNAE.
This document is currently submitted to the CEN Enquiry.
This document has been prepared under a standardization request addressed to CEN by the European
Commission. The Standing Committee of the EFTA States subsequently approves these requests for its
Member States.
For the relationship with EU Legislation, see informative Annex ZA, which is an integral part of this
document.
prEN 4709-008:2024 (E)
1 Scope
This document provides technical specification and verification methods to support compliance with
Commission Delegated Regulation (EU) 2020/1058 of 27 April 2020 amending Delegated Regulation
(EU) 2019/945 on unmanned aircraft systems and on third-country operators of unmanned aircraft
systems.
More specifically, it addresses compliance with class C5 accessories kit requirements.
Even if security, including IT security, may be useful from an operational point of view, it falls outside
the scope of this document.
This document delineates how a product compliance for the C5 accessories performance and reliability
of the safety equipment can be ensure. The specifications will ensure that the manufacturer’s C3
compliance is not altered by the accessories kit.
This document only addresses UA with lift provided by rotary wings. Fixed wings, VTOL and other
hybrid UA are out of this scope.
Compliance with this document assists in complying with CE marking technical requirements.
This document is only applicable for UA with energy sources based on electro-chemical technologies.
Additional hazards that occur from the characteristics of the payload are excluded and are, conversely,
under the responsibility of the UAS manufacturer and UAS operator.
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.
prEN 4709-001:2021, Aerospace series — Unmanned Aircraft Systems — Part 001: Product
requirements and verification methods
prEN 4709-004:2020, Aerospace series — Unmanned Aircraft Systems — Part 004: Lighting
requirements
prEN 4709-006:2023, Aerospace series - Unmanned Aircraft Systems - Part 006: Means to terminate
flight, requirements, and verification
prEN 4709-007:2024, Aerospace series - Unmanned Aircraft Systems - Part 007: General product
requirements for UAS of classes C5 and C6
At draft stage.
prEN 4709-008:2024 (E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology 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
CE marking
marking by which the manufacturer indicates that the product is in conformity with the applicable
requirements set out in Union harmonization legislation providing for its affixing
3.2
kit provider
legal entity that provides the C5 accessory kit and accompanying requisites under their name or
trademark
3.3
qualified kit integrator
legal or natural entity with a suitable level of expertise and knowledge qualified to proceed with the
installation and the verification of the kit
3.4
manufacturer serial number
unique sequence of alphanumerical characters assigned to the UA by its manufacturer in ANSI/CTA-
2063-A-2019 format
3.5
means to reduce the effect of the UA impact dynamics
technical means as part of a UAS that prevent major impact damage to mitigate the risk that the remote
pilot does not activate the means to terminate the flight in time, fearing the damage and the potential
destruction of the UA
3.6
payload
instrument, mechanism, equipment, part, apparatus, appurtenance, or accessory, including
communications equipment, that is installed in or attached to the aircraft, and is not used or intended to
be used in operating or controlling an aircraft in flight, and is not part of an airframe, engine, or
propeller
3.7
UA
aircraft operating, or designed to operate, autonomously or to be piloted remotely without a pilot on
board
3.8
UA class
C0 to C6 class identification label of UA as defined in Regulation (EU) 2019/945
3.9
UA configuration
basic design arrangement of the UA: fixed-wing, rotary wing, or multicopter
prEN 4709-008:2024 (E)
3.10
UAS
unmanned aircraft and its associated elements which are operated with no pilot on board
3.11
UAS software
software running on board UA or at its associated elements such as the command unit
3.12
UAS software modification
modification of UA software that is not documented by the original UA manufacturer in its instructions
[SOURCE: ISO/CD 21384-2.]
4 Product requirements and compliance for accessories kit transforming a C3-
class UAS into a C5-class UAS
4.1 UA configuration
4.1.1 Requirements
(1) An accessories kit may only ensure conversion of a class C3 UAS.
(2) The class C3 UAS is not a fixed wing one.
(3) The class C3 UAS provides the necessary interfaces to the accessories.
4.1.2 Verification method
Requirement (1)
Verify that the kit comes with a list of compatible UAS and that each one of them is of class C3. If the
UAS has different possible configurations (payloads, etc.), the list shall provide details of the compatible
configurations. Each compliant UAS shall be identified by its version and its software version.
Requirement (2)
Verify that the UAS listed in the manufacturer’s instructions for which the kit provides conversion is not
fixed wings whether or not equipped with a VTOL capability ones unless tethered.
Requirement (3)
Review the installation instructions provided with the kit and test the mounting of the kit on all the
compliant UAS. The compliant UAS addressed by the kit shall have the necessary interface so that the
kit can be integrated on them. The kit shall describe the interface needed for its mounting. Interfaces
can be not mandatory if the kit can be fitted without any interfaces. As of the published date of this
specification, no standard has defined an interface for FTS or PRS. In the absence of a defined interface,
the accessory kit manufacturer may describe an acceptable existing interface present on the compatible
UAS.
Refer to 4.3.2.1 for description of the means to check compatibility.
prEN 4709-008:2024 (E)
4.1.3 Pass criteria
(1) The manufacturer's instructions of the kit include a list of compatible UAS. The list describes the
compatible configurations for each UAS for which several configurations are possible. A Declaration of
Conformity covering Regulation (EU) 2019/945 and indicating a C3 type is provided (in the technical
file) for each UAS included in the list.
(2) The design of the UA does not include features that can be assimilated to wings generating lift
and enabling the aircraft flying horizontally.
(3) The interface proposed is an existing interface (for example, battery connectors for FTS).
No interface is specifically added on the UAS for the accessory kit.
The kit is well mounted on the proposed interface following the installation instructions provided by
the kit.
4.2 UAS software configuration
4.2.1 Requirements
(1) The accessories kit shall not include changes to the original software of the class C3 UAS.
NOTE The kit can include software configuration instructions for setting some parameters in the original
software present in the UA.
4.2.2 Verification method
Requirement (1)
Verify by design review that the kit functionalities are independent from the software of the drone. If
there is software communication between the kit and the drone, those shall be described and there
shall have no impact on the main functionalities: FTS and means to reduce impact energy. The design
shall indicate which software version the kit is applicable to.
4.2.3 Pass criteria
(1) The design review proves independence of the kit from the software of the UA. The kit comes
with a list of compatible software versions.
4.3 UAS original C3 compliance
4.3.1 General
The kit shall not alter the original compliance of the class C3 UAS.
4.3.2 MTOM
4.3.2.1 Requirements
(1) The mass of the combination of the UA with items included in the kit shall not exceed the MTOM
of class C3.
4.3.2.2 Verification method
Requirement (1)
— Review the packaging, identify all the items provided with the kit in the different packaging and
draw-up the list of items that are fitted to the UA.
— Determine the masses of all items that are fitted to the UA in the list of items and determinate the
mass according to the weighing procedure described below.
prEN 4709-008:2024 (E)
— Determine the total mass of the different compatible configurations of the UA in combination with
the items of the kit.
Weighing procedure:
1. weigh the item;
2. record the mass.
The weighing device with a resolution of at least 10 g shall be calibrated and the determined accuracy
shall be < ± 50 g.
4.3.2.3 Pass criteria
(1) Verify that the take-off mass of the UA in combination with the accessories declared in the
accessories manufacturer’s instruction that are fitted to the UA is not exceeding the MTOM of the C3
UAS as declared by the C3 UAS manufacturer with a ± 2 % margin.
4.3.3 Maximum characteristic dimension
4.3.3.1 Requirements
(1) The maximum characteristic dimension of the UA in combination with the kit shall be less than
3 m. If the manufacturer of the C3 compatible UA has defined some limitation regarding payloads
dimensions, those shall be taken into account.
4.3.3.2 Verification method
Requirement (1)
Apply verification method of prEN 4709-001:2021, 7.2.2.1 to the UA in combination with the
accessories.
4.3.3.3 Pass criteria
(1) Verify that the maximum characteristic dimension of the UA in combination with the items of
the kit is less than 3 m.
4.3.4 Safely controllable
4.3.4.1 Requirements
(1) The class C3 UA in addition with the kit installed on it shall be safely controllable with regard to
stability, maneuverability and the command-and-control link performance, by a remote pilot with
adequate competency and following the manufacturer’s instructions, as necessary under all
anticipated operating conditions including following the failure of one or, if appropriate, more systems.
4.3.4.2 Verification method
Requirement (1)
To show compliance with this requirement, manufacturers of kit shall apply the requirements and
verification methodology given in prEN 4709-001:2021, 6.3.1 and 6.3.2 to the UA in combination with
the items of the kit installed.
More information can be found in Regulation (EU) 2019/947.
prEN 4709-008:2024 (E)
4.3.4.3 Pass criteria
The pass criteria given in prEN4709-001:2021, 7.4.2 apply to the UA in combination with the items of
the kit installed.
4.3.5 Tethered UA
4.3.5.1 Requirements
(1) If tethered heavier-than-air aircraft, the strength of the tethering system is 10 times the weight
of the UA in combination with the accessories kit.
4.3.5.2 Verification method
Requirement (1)
To show compliance with this requirement, manufacturers of kit shall apply the requirements and
verification methodology given in prEN 4709-001:2021, 7.5.2 to the UA in combination with the items
of the kit installed.
4.3.5.3 Pass criteria
The pass criteria given in prEN 4709-001:2021, 7.5.3 apply to the UA in combination with the items of
the kit installed.
4.3.6 Power
4.3.6.1 Requirements
(1) The items of the kit are powered by electricity.
4.3.6.2 Verification method
Requirement (1)
To show compliance with this requirement manufacturers of kit shall apply the methodology given in
prEN 4709-001:2021, 4.6 to the items of the kit.
4.3.6.3 Pass criteria
The pass criteria given in prEN 4709-001:2021, 4.6.2 apply to the items of the kit.
4.3.7 Data link protection
4.3.7.1 Requirements
(1) The items of the kit, unless tethered, shall be equipped with a command-and-control link
protected against unauthorized access.
4.3.7.2 Verification method
Requirement (1)
To show compliance with this requirement manufacturers of kit shall apply the methodology given in
prEN 4709-001:2021, 6.7.2 to the command-and-control link of the items of the kit.
NOTE The kit can consist of items that don’t need data link to operate (ex. FTS activated automatically with
geocaging functions). In this case, this requirement doesn’t apply.
prEN 4709-008:2024 (E)
4.3.7.3 Pass
...