الهيئة السعودية للمواصفات والمقاييس  والجودة  
Saudi Standards, Metrology and Quality Org (SASO) 
 
 
 
 
 
 
 
 
 
 
SASO DS ISO 21895 :2023  
ISO 21895:2020 
 
 
تصنيف وفئات أنظمة الطائرات بدون طيارالمدنية  
Categorization and classification of civil unmanned 
aircraft systems  
 
ICS: 49.020  
 
THIS  DOCUMENT IS A DRAFT SAUD I STANDARD 
CIRCULATED FOR COMMENT. IT IS, THEREFORE SUBJECT TO 
CHANGE AND MAY NOT BE REFERRED TO AS A SAUDI 
STANDARD UNTIL APPROVED BY THE BOARD OF 
DIRECTORS.   
 ISO 21895:20 20(E) 
2 © ISO 2019  – All rights reserved  
 Foreword  
 
Saudi Standards, Metrology and Quality Organization (SASO) has adopted 
Standard No. (ISO 21895:2020) “Categorization and classification of civil 
unmanned aircraft systems” issued by ( ISO) in English. This standard has be en 
approved as a Saudi Standard with national modifications.  
 
 
This SASO ISO  21895 :2023 standard is a modified adoption of International 
Standard IEC 21895 :2020, ( Categorization and classification of civil unmanned 
aircraft systems ). Standard has been varied as indicated to take account of 
Kingdom of Saudi Arabia conditions. The modifications are specified in Annex 
A. 
  ISO/FDIS  21895:2019(E)  
© ISO 2019  – All rights reserved  iii 
 INTERNATIONAL STANDARD  
ISO 21895:2020(E)  
Date:    2020 -02 
 
ISO/TC  20/SC  16/WG  1 
Secretariat:    ANSI  
Categorization and classification of  civil unmanned aircraft systems  —  
Catégorisation et classification des aéronefs civils sans pilote  —   
iv © ISO 2020 – All rights reserved  
 COPYRIGHT PROTECTED DOCUMENT  
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copyright@iso.org  
www.iso.org  ISO 21895:20 20(E) 
© ISO 2020 – All rights reserved  v 
 Contents  Page  
Foreword  ................................ ................................ ................................ ................................ ................................ .........  iv 
Introduction  ................................ ................................ ................................ ................................ ................................ ..... v 
1 Scope  ................................ ................................ ................................ ................................ ................................ ....1 
2 Normative references  ................................ ................................ ................................ ................................ ....1 
3 Terms and definitions  ................................ ................................ ................................ ................................ ....1 
4 Classification and grading principle  ................................ ................................ ................................ ......... 2 
5 Classification  ................................ ................................ ................................ ................................ ..................... 4 
5.1 UA-configurati on ................................ ................................ ................................ ................................ .............. 4 
5.2 Mode of launch and recovery/take -off and landing  ................................ ................................ ............ 5 
5.2.1  Mode of launch/take -off ................................ ................................ ................................ ................................ 5 
5.2.2  Mode of recovery/landing  ................................ ................................ ................................ ............................ 5 
5.3 Engine/powerplant type and energy source  ................................ ................................ ......................... 5 
5.3.1  Engine/powerplant type  ................................ ................................ ................................ ............................... 5 
5.3.2  Energy source  ................................ ................................ ................................ ................................ .................... 6 
5.4 Control mode  ................................ ................................ ................................ ................................ ..................... 6 
5.5 Maximum achiev able height  ................................ ................................ ................................ ........................ 6 
5.6 Maximum airspeed ................................ ................................ ................................ ................................ .......... 7 
5.7 Flight endurance  ................................ ................................ ................................ ................................ .............. 7 
5.8 C2-link coverage  ................................ ................................ ................................ ................................ ............... 7 
5.9 Kinetic energy  ................................ ................................ ................................ ................................ ................... 7 
5.10  Identification mode  ................................ ................................ ................................ ................................ ......... 9 
6 Grading  ................................ ................................ ................................ ................................ ................................ 9 
  
vi © ISO 2020 – All rights reserved  
 Foreword  
ISO (the International Organization for Standardization) is a worldwide federation of national 
standards bodies (ISO member bodies). The work of prep aring International Standards is normally 
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www.iso.org/iso/foreword.html . 
This document was prepared by Technical Committee ISO/TC  20, Aircraft and space vehicles , 
Subcommittee SC  16, Unmanned aircraft systems . 
Any feedback or questions on this document should be directed to the user’s national standards body. A 
complete listing of these bodies can be found at www.iso.org/members.html . ISO 21895:20 20(E) 
© ISO 2020 – All rights reserved  vii 
 Introduction  
This document se ts out a methodology for the multi -dimensional classification of unmanned aircraft 
system (UAS). The purpose of this classification model is not to replace any existing regulatory model 
but to provide a more granular classification tool for use by those wh o need to approach the 
classification of UAS from their own perspective and for whom the regulatory model is too broad. 
Examples may be but are not limited to; engineers, manufacturers, certification bodies, insurance 
underwriters or accident investigators . INTERNATIONAL STANDARD  ISO 21895:20 20(E)  
 
© ISO 2020 – All rights reserved  1 
 Categorization and classification of civil unmanned aircraft 
systems  
1 Scope  
This document specifies requirements for the classification and grading of civil unmanned aircraft  
system (UAS). This document applies to heavier than air aircraft as well as lighter than air aircraft of 
any possible architecture.  
This document applies to the industrial conception, development, design, production and delivery of 
civil UAS. It also appl ies to modification, repair and maintenance of civil UAS.  
The characteristics in this document can be used individually or in combination, to meet specific needs 
of the classification and grading of civil  UAS.  
Risk -based categorization of UAS  operations is  prerogative of the aviation authorities and it is hence out 
of scope of this document.  
2 Normative references  
The following document is referred to in the text in such a way that some or all of their content 
constitutes requirements of this document. For da ted references, only the edition cited applies. For 
undated references, the latest edition of the referenced document (including any amendments) applies.  
ISO 21384 -41, Unmanned aircraft systems  — Part  4: Vocabulary  
3 Terms and definitions  
For the purposes of  this document, the terms and definitions given in ISO 21384 -4 and the following 
apply.  
ISO and IEC maintain terminological databases for use in standardization at the following addresses:  
— ISO Online browsing platform: available at http://www.iso.org/obp  
— IEC Electropedia: available at http://www.electropedia.org/  
3.1 
multicopter  
rotorcraft lifted by more than two power driven rotors on substantially vertical axis  
3.2 
aerostat  
lighter than air aircraft  
                                                             
1 Under preparation. Stage at the time of publication: ISO/DIS 21384 -4:2019.   
2 © ISO 2020 – All rights reserved  
 4 Classification and grading principle  
Civil UAS  classification is proposed from different viewpoints, which are subsequently categorized and 
graded against a stakeholder specific rule set. The framework provides a valuable  tool for all 
stakeholders in the industry to categorize UAS from their perspective and the perspective of others.  
Figure  1 shows a conceptual structure of the UAS classification framework.  ISO 21895:20 20(E) 
© ISO 2020 – All rights reserved  3 
  
Figure  1 — Civil UAS classification framework  
 
4 © ISO 2020 – All rights reserved  
 Figure  2 shows an example for grading framework under fixed wing, helicopter and multicopter.  
 
Figure  2 — Example for grading framework under fixed -wing, helicopter and multicopter  
5 Classification  
5.1 UA-configuration  
According to the UA -configuration, an unmanned air craft (UA) shall be classified as follows:  
a) powered fixed -wing plane (or aeroplane);  
b) glider;  
c) single rotor helicopter;  
d) multicopter;  
e) gyroplane;  
f) parawing, flapping -wing (ornithopter) and other bio -inspired aircraft;  
g) vertical take -off and landing (VTOL), other than helicopter or multicopter;  
h) airships;  
i) tethered or free aerostatic balloons;  
j) tethered heavier than air aircraft (e.g. kites);  
k) aerostat;  
ISO 21895:20 20(E) 
© ISO 2020 – All rights reserved  5 
 l) others.  
5.2 Mode of launch and recovery/take -off and landing  
5.2.1  Mode of launch/take -off 
The mode of launch/take -off, from an aerodrome, from an elevated platform, from water or from a 
floating platform, shall be classified as follows:  
a) horizontal rollout take -off; 
b) vertical take -off; 
c) guide rail kinetic energy ejection (e.g. catapult):  pneumatic pressure, hydraulic pressure, rubber -
cord, electromagnetism, etc.;  
d) release of the tethering cable (e.g. by a winch);  
e) released in flight from another aircraft;  
f) manually launched take -off; 
g) others.  
Several of these modes may be rocket assisted or rocket propelled.  
5.2.2  Mode of recovery/landing  
The mode of recovery/landing shall be classified as follows:  
a) horizontal rollout landing;  
b) vertical landing;  
c) parachute recovery;  
d) intercepted in flight by a recovery aircraft;  
e) net/rope reco very;  
f) pulling of the tethering cable;  
g) pneumathode recovery (parachutes, airbags or other kinds of shock absorbers);  
h) others.  
5.3 Engine/powerplant type and energy source  
5.3.1  Engine/powerplant type  
The engine/powerplant type shall be classified as follows:  
a) piston engine;  
b) turbine engine;   
6 © ISO 2020 – All rights reserved  
 c) rotary expansion engine;  
d) electric motor;  
e) rocket engine;  
f) compressed air power plant;  
g) combination/mixed power plant;  
h) others.  
5.3.2  Energy source  
The energy source of dynamic force production shall be classified as follows:  
a) gaseous fuel: hydrogen, etc.;  
b) liquid fuel: jet fuel (heavy oil), methanol, gasoline, diesel fuel;  
c) battery: lithium battery, nickel -metal hydride battery, fuel battery, etc.;  
d) combination/mixed energy source;  
e) others: sol ar energy, wind energy source, air upstream energy, etc.  
5.4 Control mode  
In terms of control mode, it shall be divided into:  
a) manual (control) mode: the drivers use continuous instruction by way of the flight control system 
to realize direct piloting (human  in the loop);  
b) automatic (control) mode: according to pre -entered flight instructions, onboard systems, in the 
case of basically needing no intervention, automatically and continuously complete the entire flight 
(human on the loop);  
c) autonomous (contr ol) mode: program control flight with self -adaptive and self -decision -making 
abilities (human out of the loop).  
The control mode may vary during different phases of flight.  
5.5 Maximum achievable height  
The maximum intended height shall be classified as:  
a) very low level:  
1) level  I: maximum height  ≤ 15 m (above ground level);  
2) level  II: 15  m (above ground level)  < maximum height  < 120  m (above ground level).  
b) medium level:  
1) level  III: 120  m (above ground level)  ≤ maximum height  ≤ 1 500  m (above ground level);  ISO 21895:20 20(E) 
© ISO 2020 – All rights reserved  7 
 2) level  IV: 1  500  m (above ground level)  < maximum height  ≤ 18 300  m (standard air pressure 
altitude).  
c) very high level:  
1) level  V: maximum height  > 18 300  m (flight level 600 standard air pressure altitude).  
5.6 Maximum airspeed  
The maximum airspe ed shall be divided into:  
a) level  I: maximum airspeed  ≤ 70 km/h;  
b) level  II: 70  km/h  < maximum airspeed  ≤ 0,15  Ma; 
c) level  III: 0,15  Ma < maximum airspeed  ≤ 0,3 Ma; 
d) level  IV: 0,3  Ma < maximum airspeed  ≤ 0,8 Ma; 
e) level  V: 0,8  Ma < maximum airspeed  ≤ 1,2 Ma (transonic speed);  
f) maximum airspeed  > 1,2 Ma (supersonic speed).  
NOTE  Ma stands for mach number.  
5.7 Flight endurance  
The flight endurance after initiation at the maximum take -off mass shall be divided into:  
a) level  I: endurance  ≤ 0,5 h; 
b) level  II: 0,5  h < endurance  ≤ 1 h; 
c) level  III: 1  h < endurance  ≤ 6 h; 
d) level  IV: 6  h < endurance  ≤ 24 h; 
e) level  V: endurance  > 24 h. 
5.8 C2-link coverage  
C2-link coverage shall be divided into:  
a) level  I: operating radius  ≤ 1,5 km; 
b) level  II: 1,5  km < operating radius  ≤ 15 km; 
c) level  III: 15  km < operating radius  ≤ 200  km; 
d) level  IV: operating radius  > 200  km. 
Level  IV typically requires a network of ground radio stations or satellite communication.  
5.9 Kinetic energy  
In terms of kinetic energy, it sha ll be divided into:   
8 © ISO 2020 – All rights reserved  
 a) level  I: kinetic energy  ≤ 80 J; 
b) level  II: 80  J < kinetic energy  ≤ 10 kJ; 
c) level  III: 10  kJ < kinetic energy  ≤ 100  kJ; 
d) level  IV: 100  kJ < kinetic energy  ≤ 1 000  kJ; 
e) level  V: kinetic energy  > 1 000  kJ. 
Calculate kinetic ener gy according to Formula  (1): 
2
DN DX1
2E mV
 (1) ISO 21895:20 20(E) 
© ISO 2020 – All rights reserved  9 
 where  
  EDN is the flight impact kinetic energy, in J;  
  m is the UA mass, in kg;  
  VDX is the equivalent of 1,4  times of the maximum flight speed for fixed wing aeroplanes,  
in m/s.  
5.10 Identification mode  
The identification mode shall be classified as follows:  
a) unmanned aircraft legally exempted from registration (identification by registration impossible);  
b) unmanned aircraft with a fixed label or plate containing registration data (identification possible 
only in a proximate range of the aircraft);  
c) electronic identification based on a standard specifically developed for unmanned aircraft (the 
identification device may be active or passive, but not necessarily cooperative with man ned 
aircraft);  
d) ATC transponder or equivalent ADS -B capability (in this way the unmanned aircraft becomes 
cooperative with manned aircraft).  
6 Grading  
According to the maximum take -off mass, the UA shall be graded as in Table  1. 
Table  1 — Graded by the max imum take -off mass  
Level  Maximum take -off mass  
kg 
I 0 < mass  ≤ 0,25  
II 0,25  < mass  ≤ 0,9 
III 0,9 < mass  ≤ 4 
IV 4 < mass  ≤ 25 
V 25 < mass  ≤ 150  
VI 150  < mass  
  
 
 
 
 
 
 
 
  
10 © ISO 2020 – All rights reserved  
 Annex A: List of National modifications  
(Normative)  
 
No Clause/Subclause  
 Text as specified in:  
ISO 21895 :2020  National Modification  
1 3  
Terms and 
definitions  -  Refer to the follow website for 
more definitions  (Satellite 
(gaca.gov.sa) )  
2 -  -  Dual copter  is included within 
the scope of this standard  
3 -  -  The measurement unit shall be 
presented as follow :  
It is indicated in feet (ft) with 
the additional inclusion of 
mete rs (m) enclosed in 
parentheses.