The flying Fiaker: A case study

25 February 2020 | blog

The Fiaker, a Viennese term for a horse-drawn four-wheeled carriage for hire (a "hackney coach"), has been trundling through the streets of Vienna for centuries. The first Fiaker was licensed in 1693. Back then, it was the first means of urban transportation to carry several passengers at once. Today, it is a tourist attraction and traffic obstruction. Nonetheless, the Fiaker survived and adapted. Just recently, the first electronic Fiaker hit the road in Vienna.1

It is heralded that the future of urban transportation lies in the third dimension: up! Soon drones will usher in a new era of urban aerial mobility. With the U-Space initiative, the European Commission established a process to develop a new regulatory framework that would enable complex (civil)2 drone operations in all types of operational environments within the single European Sky airspace.3 This new EU framework must be widely implemented by EU Member States starting from 1 July 2020 and is fully applicable to all civil drone operations as of 1 July 2022.

The scenario

Now, let's imagine that flying drone taxis become technically feasible. It is most likely that the Fiaker will not stay on the ground but will also evolve with this new technology. Using the example of a "flying Fiaker", this case study briefly analyses the legal requirements for the production and operation of a drone taxi under the new EU legal framework for unmanned aircraft systems ("UAS").4

For this, the flying Fiaker will be operated and owned by an UAS operator established in Vienna and should be registered in Austria. The flying Fiaker will allow tourists to take a unique roundtrip over Vienna's historic city centre. It will transport up to four passengers. But instead of being pulled by two horses, it will be powered by multiple rotors. Furthermore, the flying Fiaker will be autonomously operated, with no need for a driver or remote pilot.

The new legal framework

The revised Basic Regulation 2018/1139 ("BR") is the cornerstone of the new regulatory framework for civil aviation in the EU. Regarding UAS, the Delegated Regulation (EU) 2019/945 ("DR") harmonises the technical requirements for their design and production and the Implementing Regulation (EU) 2019/947 ("IR") sets out the rules and procedures for their operation. For an in-depth analysis of the new regulatory framework for UAS and its consequences to Austrian and EU aviation law, please see our previous article: Does Austrian aviation law comply with the new EU rules for drones?.

Subject matter

Design, production, maintenance (technical requirements) and operation of an UAS, its parts and equipment and the personnel involved fall under the new EU drone law, if (for example) the UAS is or will be registered in a Member State and is operated (in Austria) by an UAS operator established in EU (Austria).5 Any national authorisations or certificates are already available for the UAS operator.6 As an UAS, the flying Fiaker and its Viennese operator are subject to the new EU drone law from 1 July 2020.


The flying Fiaker will be designed to transport up to four passengers. According to Art. 40 DR, the design, production and maintenance of UAS require certification if the UAS is intended to transport people7. Regarding the certification requirements, the DR refers to relevant provisions for manned aircraft.8

Just like manned aircraft, the flying Fiaker will require a (restricted) type certificate as well as a (restricted) certificate of airworthiness ("CofA"). The design and production organisations will have to observe the requirements for Design/Production Organisation Approvals. These certificates will be issued in accordance with Part 21.9 Furthermore, the common technical requirements for ensuring the continuing airworthiness will be applicable.10

Concerning the type certificate, however, the European Aviation Safety Agency (EASA) has neither determined UAS-specific certification specifications ("CS")11 nor revised the existing CS developed for manned aircraft to reflect the peculiarities of UAS. According to the EASA's concept,12 the type certification will be based on a determination of equivalence with existing CS13 as well as special conditions ("SC") prescribed by the EASA on a case-by-case basis.14


The IR lays down the rules for operating UAS. A clear risk-based approach to establish three categories of UAS operations follows, each with its own operational requirements. The "certified" category15 will cover UAS operations with the highest risk: over assemblies of people, transport of people or16 the carriage of dangerous goods.17 UAS operated in the certified category are subject to classic aeronautical compliance procedures. These include the certification of the UAS pursuant to Art. 40 DR (cf. above point "Production"), certification of the operator (air operator certificate, "AOC") and where applicable, the licensing of the remote pilot.18 Operational requirements for manned aviation will be applicable for UAS operations in the certified category, too.19

As the flying Fiaker will be used for passenger transportation, its operation will fall under the "certified" category. Thus, the flying Fiaker is subject to classic aeronautical procedures. The Viennese operator must observe technical requirements and administrative procedures, particularly the requirement to obtain an AOC.20 In flight, the flying Fiaker will also have to comply with the rules of the air ("SERA").21 Owning the flying Fiaker, the Viennese operator aims to register it in Austria in line with ICAO Annex 7 and the competent national authority must issue a unique digital registration number for the flying Fiaker allowing its individual identification.22


With the adoption of the new legal framework, UAS have finally received the attention they urgently deserve. The EU and EASA have concentrated so far on the technical and operational specifications of UAS operating in the "open" and "specific" category.

For the still futuristic "certified" category the new EU legal framework does not determine details on its own, but broadly refers to legal provisions on manned aviation. This, at least in some points, does not seem to be totally adequate. Any case of well-grounded inadmissibility to apply aircraft law for manned aviation to UAS may cause a regulatory gap. To outline just a few examples:

  • Missing UAS-specific CS bring uncertainty in the type certification process.
  • According to SERA.2010 and SERA.2015, the pilot in command of an aircraft is responsible for the operation of the aircraft in accordance with SERA and has final authority as to the disposition of the aircraft while in command.
  • Air traffic control services heavily rely on communication with the pilot. Accordingly, SERA.6001 prescribes the requirement of continuous air-ground voice communications for most airspaces.
  • Certain obligations of the operator usually require personnel on board of the aircraft. According to CAT.GEN.MPA.17023, the operator will take all reasonable measures to ensure that no person enters or is in an aircraft when under the influence of alcohol or drugs. Without a pilot or crew members on board24 it is unclear how the operator can assure compliance with these obligations.

For our flying Fiaker, many questions remain unresolved. The (partly) equal treatment of UAS with manned aircraft gives us a first idea of the requirements for the construction and operation of the flying Fiaker. However, the true integration of UAS into "manned" airspace will require further regulatory action.


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2 Military drones or drone operations under the responsibility of a Member State in public interest (e.g. police, firefighting, border control) still fall under the competency of EU Member States.

3 SESAR, European ATM Master Plan 4

4 Unmanned aircraft (UA) means any aircraft operating or designed to operate autonomously or to be piloted remotely without a pilot on board. Unmanned aircraft system (UAS) means an UA and the equipment to control it remotely.

5 Cf. Art. 2 (1) (b) no. 1 BR.

6 Art. 21 (1) IR; the current EU drone law (Reg [EU] 216/2008) is applicable to drones with a mass over 150 kg.

7 Art. 40 (1) (b) DR.

8 Art. 40 (2) DR.

9 Annex I to Commission Regulation (EU) 748/2012; cf. also Part 26 according to Commission Regulation (EU) 2015/640.

10 In accordance with Art. 3 Commission Regulation (EU) 1321/2014.

11 See 21.A.16A of Part 21 Commission Regulation (EU) 748/2012.

12 EASA, Certified category operations of UAS, certification of UAS and UAM operations (Concept Paper) 16

13 E.g. CS-23 for normal-category aeroplanes or CS-27 for small rotorcraft.

14 Cf. 21.A.16B of Part 21 Commission Regulation (EU) 748/2012.

15 According to a current EASA opinion (05/2019) any modifications are intended for the certified category.

16 Cf. linguistic mistakes or ambiguities in the German version of the legal framework (esp. Art. 6 IR).

17 Art. 6 IR.

18  Art. 3 lit c IR.

19  Art. 7 (3) IR.

20 As prescribed by Commission Regulation (EU) 965/2012.

21 Implementing Regulation (EU) 923/2012.

22 Art. 14 (1), (3), (6), (7), Art. 18 lit m IR.

23 Cf. Annex IV Commission Regulation (EU) 965/2012.

24  As the flying Fiaker does not exceed a maximum operational passenger seating configuration (MOPSC) of more than 19, no cabin crew member is to be assigned (cf. Annex III ORO.CC.100 Commission Regulation (EU) 965/2012).