EuroUSC Italia


EU Programme: EDA – PP-15-STAN-CERT-01

DURATION: 18 months | November 2016 – April 2018|

STATUS: Closed


CONTACTS: filippo.tomasello@eurousc-italia.


The TRAWA project aimed to contribute to the development of standards for self-separation in support of EUROCAE WG 73. The ICAO Manual (Doc 10019) on Remotely Piloted Aircraft Systems, identifies five hazards which a ‘Detect and Avoid’ (D&A) system could mitigate. Among them, ‘conflicting traffic’ is the most prominent.

To mitigate the risk of Mid-Air Collision (MAC) with such traffic, mitigations could be implemented in the ‘strategic’ phase (e.g. prior to take-off to avoid airspace congestion), in the ‘tactical’ phase or, as a last resort, for ‘collision avoidance’ (CA). The ‘strategic’ phase is covered by EuroUSC Italia in project DREAMS. The CA phase, at least with co-operative traffic, has been studied for several decades also for manned aviation (i.e. ACAS or similar). In the ‘tactical’ phase a safe distance between the Unmanned Aircraft (UA) and the conflicting traffic can be ensured by Air Traffic Control (ATC) or through the ‘Remain Well Clear’ (RWC) function of D&A implemented in the UAS. RWC is absolutely necessary on uncontrolled airspace (i.e. Class G), but it could be very useful in relation to VFR traffic also in airspace Classes D and E.

TRAWA project concluded that:

  • In the RWC phase, contrary to the CA phase, rules of the air should apply;
  • It is better to inform the remote pilot about headings which would lead to an increased risk of MAC, without suggesting her/him a recommended manoeuvre (e.g. turn right or turn left); 
  • Colour coding should be similar to what is today used in manned aircraft (i.e. green, white, amber, red).


EuroUSC Italia contributed to TRAWA to develop the safety requirements for the Human-Machine Interface (HMI) of the RWC function, which in fact requires some sensors on board the UA, but also some display to the remote pilot on the ground. Furthermore, EuroUSC Italia has revised the Minimum Operational Performance Specifications (MOPS) developed by TRAWA, to validate their compliance with emerging provisions on D&A from ICAO (e.g. new Part IV of Annex 6), from JARUS and with EASA regulatory material.


  • NLR – Nederlands Lucht- en Ruimtevaartcentrum
  • DLR – Deutsches Zentrum fur Luft und Raumfahrt
  • Deep Blue
  • EuroUSC Italia
  • Tony Henley Consulting