prEN 4709-008

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

Aeronavtika - Letalski sistemi brez posadke - 008. del: C5 Dodatni kompleti

General Information

• Status: Not Published
• Publication Date: 31-Aug-2025
• ICS: 49.020 - Aircraft and space vehicles in general
• Technical Committee: CEN/TC 471 - Aviation and aeronautics
• Drafting Committee: CEN/TC 471/WG 1 - Unmanned Aircraft Systems
• Current Stage: 4060 - Closure of enquiry - Enquiry
• Start Date: 23-May-2024
• Completion Date: 23-May-2024
• Directive: 2019/945 - Commission Delegated Regulation (EU) 2019/945 of 12 March 2019 on unmanned aircraft systems and on third-country operators of unmanned aircraft systems
• Mandate: M/567 - Standardisation Request to the European Committee for Standardisation as regards unmanned aircraft systems intended to be operated in the ‘open’ category of operations in support of Commission Delegated Regulation (EU) 2019/945
• Ref Project: oSIST prEN 4709-008:2024 - Aerospace series - Unmanned Aircraft Systems - Part 008: C5 Accessories kits

Overview

prEN 4709-008:2024 - "Aerospace series - Unmanned Aircraft Systems - Part 008: C5 Accessories kits" is a draft CEN standard that specifies technical requirements and verification methods for accessories kits intended to convert class C3 rotary‑wing UAS into C5 UAS. The document supports compliance with EU Delegated Regulation (EU) 2020/1058 (amending 2019/945) and helps manufacturers, kit providers and integrators demonstrate product conformity for CE marking. It applies to rotary‑wing UAs with electro‑chemical energy sources and excludes fixed‑wing, hybrid/VTOL (except tethered), payload‑specific hazards and IT security.

Key topics and requirements

The standard focuses on product performance, reliability and verification. Major technical topics include:

• UA compatibility and configuration

  • Kits must target C3 UAS (non‑fixed wing) and list compatible UAS models, configurations and software versions.
  • Interfaces required for mounting must be documented; kits may include or describe acceptable non‑standard interfaces.

• Product and software requirements

  • Verification methods and pass criteria for UA configuration and UAS software configuration changes.
  • Controls to ensure the kit does not invalidate the UAS’s original C3 compliance (e.g., MTOM, maximum characteristic dimensions, controllability).

• Safety equipment and functions

  • Means to terminate flight (FTS) and other means to reduce impact dynamics (e.g., parachute systems) are covered, with example test procedures in informative annexes.
  • Post‑installation checks such as low‑speed mode, C2 link monitoring and accessory‑link alerting, and documented means to terminate flight.

• Installation, instructions and documentation

  • Requirements for accessories lists, installation procedures, testing, and a kit manual structure (annexes provide examples).
  • Roles defined: kit provider, qualified kit integrator, and traceability via manufacturer serial numbers.

Practical applications and users

Who uses prEN 4709-008:

• Accessories kit providers developing retrofit safety kits for C3 rotary UAS to meet C5 performance.
• Qualified kit integrators performing installations and verifications per the standard.
• UAS manufacturers assessing compatibility and ensuring original conformity is maintained.
• Certification bodies and conformity assessors evaluating kits against EU delegated regulation requirements.
• UAS operators seeking approved upgrade paths to meet higher safety classes.

Practical benefits:

• Clear verification methods for safety functions (FTS, parachutes, impact‑mitigation).
• Structured documentation to support CE marking and regulatory compliance.
• Guidance to maintain original UAS performance characteristics while adding safety accessories.

Related standards

Normative references include other Aerospace series parts:

• prEN 4709-001 (product requirements & verification)
• prEN 4709-004 (lighting)
• prEN 4709-006 (means to terminate flight)
• prEN 4709-007 (general product requirements for C5/C6)

Keywords: prEN 4709-008, C5 accessories kit, UAS, unmanned aircraft systems, C3 to C5 conversion, FTS, parachute, CE marking, verification methods, CEN.

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
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.

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
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

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.
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.
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
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.
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.
— 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.
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.
4.3.7.3 Pass
...