AESA, the Spanish National Aviation Safety Agency, has published an explanatory note regarding drone or UAS class markings as defined in Delegated Regulation EU 2019/945.
Specifically, in the Drones/UAS Requirements/List of UAS Manufacturers and Models section of its website, a note has been published explaining the regulated procedure for converting a UAS with class C5 marking using a conversion kit.
Reference is made to the regulations contained in Annex Part 16, point 8 of Delegated Regulation EU 2019/945, which indicates that an aircraft with class C3 marking can be converted to C5 using an accessory kit.
However, under no circumstances can an aircraft with class C2 marking be converted to C5.
AESA indicates that after consulting with EASA, the response was that it is not feasible to convert a UAS with class C2 marking to one with class C5 marking, as it is not a valid kit under the Regulation. This means that a C2 UAS cannot be converted to a C5, and vice versa, depending on the operator's interest and the flight category in which it will operate.
If a UAS is converted from class C2 marking to class C5 marking, it would be a new aircraft, and the modification could not be reversed. The conversion from C2 to C5 must be carried out by an approved manufacturer, who assumes responsibility for the new product. The modifying manufacturer must issue a new declaration of conformity with its new class marking.
In addition, the C2 class marking label must be removed, and the new manufacturer must provide a new serial number for the aircraft. The previous serial number, coming from a C2 marking, follows the ANSI/CTA-2063-A-2019 standard with the original manufacturer's code.
The explanatory note can be found at the following link:
https://www.seguridadaerea.gob.es/sites/default/files/Informaci%C3%B3n%20relativa%20al%20kit%20de%20conversi%C3%B3n%20C2%20a%20C5.pdf
As an additional reflection, it seems pointless to convert a UAS with a C2 class marking to a C5 for flight in an urban environment.
With a C2-class marked UAS, according to EU Implementing Regulation 2019/947, you can fly within the open A2 category in an urban environment, complying with the distance limitations from non-participants. This distance is 30 m or 5 m if flying in low-speed modes, respecting the 1:1 distance-to-height rule.
The distances from non-participants in A2 may be smaller than the mandatory controlled ground zone under the standard STS01 scenario for the specific category (UAS.STS-01.020), which is the scenario in which drones with C5-class marking can fly. Remember that this controlled ground zone is composed of the flight geography itself (the physical space where the aircraft will fly) plus a contingency zone, plus a ground risk safety zone.
Therefore, operating in subcategory A2, using a drone with class C2 marking, appears to be a simpler and safer operation, without a C5 conversion kit and without the potential complications that may arise from carrying a parachute in flight.
