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20 Dossier | Selex ES Falco UAV prevailing regulations allow that scenario). The Falco was designed to fill the gap between ‘Tactical’ and ‘MALE’ (Medium Altitude Long Endurance) UAVs. This led to compromises between the features of both types. Most fixed-wing Tactical UAVs were characterised by low weight (generally 200 to 300 kg), had a small wingspan, were launched typically by catapult and often made a parachute landing. Larger wingspan MALE UAVs had higher weight (around one tonne) and were generally able to take off and land using their own landing gear. The flight duration of Tactical UAVs was invariably less than impressive. The Falco was intended as a larger craft with much longer flight duration, which could take off and land in the manner of a conventional aircraft, ready upon touchdown for refuelling and another mission. The Falco’s 7.2 m wingspan was driven by operational considerations. In essence, the longer the wingspan, the better in terms of payload capability and flight endurance. At the same time, it was considered important that the craft could be stored in a conventional container and handled by no more than two people. Ultimately though there was clearly a trade-off to be made. To that end, it is significant that Selex ES recently developed the longer-wingspan Falco EVO to suit customers who put payload weight and endurance ahead of the aforementioned operational considerations (see sidebar: Falco EVO). UAVs smaller than the Falco have often been likened to sophisticated model aircraft. By contrast, in all respects of its design and development – including the use of finite element analysis, computational fluid dynamics (CFD) study, static and dynamic tests and so on – the Falco was treated as a real aircraft, albeit one that happens to be unmanned. The upshot was that, owing to its size and sophistication, including a full taxiing capability, the Falco would be much heavier than a typical ‘model aircraft style’ UAV, actually weighing in at 530 kg. That in turn meant careful attention had to be paid to its ‘crashworthiness’ in view of the desire to have it CAA-certified. It was necessary to study the implication of loss of control in terms of energy dissipation upon impact, following recommendations set out by the joint JAA-Eurocontrol Task Force Final Report in 2004. In this respect the Falco was a pioneer, as it was designed just before the preparation of the JAA-Eurocontrol recommendations. In the Falco’s case there was no pilot to protect within the craft; however, there is sophisticated equipment on board, and as usual the potential impact of any crash on the environment has had to be taken into account. It follows that the Falco carries a parachute for emergency use, and that in turn has driven a number of considerations in its configuration, for example the need for reinforcement of the airframe in certain areas. There was also a careful design study to maximise the probability that the parachute deploys safely and effectively, following a major failure onboard or on the pilot’s command, in all foreseeable flight conditions. Certification took into account the fact that although there would be no person on board, there would be a pilot in the loop via the GCS: even in fully autonomous mode, the pilot would continue to monitor the craft. However, in terms of the need for certification, that scenario was more tricky than the normal case of having a person always in the Dec 2015/Jan 2016 | Unmanned Systems Technology Selex ES operates a fleet of Falcos for the UN The Falco was designed to take off and land in the manner of a conventional aircraft, ready upon touchdown for refuelling and another mission