SMALL UNMANNED AIRCRAFT
There is a general view of small unmanned aircraft (SUA) as a panacea and it's one that I personally disagree with. In terms of search and rescue (SAR), for missing persons or a missing aircraft people often consider the capabilities of SUA's in the abstract.
For instance with a downed aircraft you're expecting to see a debris field and a lot of bare twisted metal that would give a wide array of reflected light. From the air this is considered, in theory, to be easy to identify. Likewise, in terms of locating a missing person, say a hill walker, it's assumed that with a SUA you can cover a large area very quickly to find someone who's usually wearing bright clothing and stands out from the terrain.
In both instances the SUA is thought to be a quick, effective solution because, from an elevated position, you can see anomalies quickly and easily. What most people don't realise is that the SUA is often more limited than traditional search methods; a ground search party supported, where possible, with a manned aircraft. It's too easy to focus on the positives abstracted from the realities of the situation.
The main limitation of a SUA deployment is the weather, principally wind speed and rain. Aircraft are often lost in bad weather conditions, as are hill walkers, and these are the conditions that have a direct effect on the feasibility of SUA operations. Some people are quick to point out that you can get waterproof SUA's without, in the case of a SUA with rotors, considering the effect the rotors play in creating a wash of rain on the camera. The airflow around a SUA is different to conventional aircraft because some rotors pull air towards them and some push air away from them. The degree to which this happens depends entirely upon the onboard computer which is balancing the different rotors to create a stable flight. As such, when flying in the rain this airflow creates a misting effect and throws water towards the camera. One manufacturer I've ever heard of, who address this point, is AscTec who question the benefit of flying observational missions in the rain, despite them manufacturing waterproof SUA's.
From my own experience, after being involved with SUA's for several years, I've seen a lot of people who are keen to promote themselves as 'experts' in the field and who sing the praises of the technology without wishing to address its limitations. Personally, I find the best understanding of the technology comes from viewing it in the same way that aerial photographers do. They refer to SUA's as "tripods in the sky" and often they're also referred to as "platforms". For me this is the best and simplest approach to understanding the technology and its limitations, because that's all that they are, tripods that can support different sensors and measuring devices that you can move around in the air.
Once seen from this perspective it's straightforward. How would you search an area on the ground? Why would you search it differently if you were 200ft higher? You still overlap the areas, you just move faster and you can see more from 200ft!
SUA's can be used to oversee a ground search in terms of providing real time footage to the 'silver command' who are coordinating, ground parties, dog teams, or boat teams. They can be used to help fire and rescue services see where their water jets are hitting and adjust their aims accordingly. The cameras can be fitted with polarised filters to see through surface reflections on water to help search waterways, and they can carry thermal cameras to help detect heat sources. They can be used to direct ground responders to a specific location by hovering over it and they can help to enhance dynamic risk assessments by identifying dangers and safe routes for ground responders to follow.
What I often see is that the collaborative approach is missing from most discussions of the technology. It's presented as a binary choice in that SUA's will replace the need for conventional approaches. This has the effect of pitching new technology against tried and trusted methods, so it becomes a divisive subject. As such, doubts and fears regarding safety, competence, and effectiveness become a focal point and overshadow the issue.
SUA's are, in my opinion, definitely not a panacea. But they are a highly effective tool that can have significant operational benefits when correctly integrated into existing responder workflows. Provided the conditions are right and there exists a potential significant benefit they should always be deployed. Whether that benefit is in terms of direct search results, or simply observational, shouldn't make a difference. For instance one fire and rescue service (FRS) unit used me to provide an overview of a training exercise so that 'silver command' could see where the search teams were operating and where their techniques could be improved. They found the footage extremely useful in their debriefs. They were able to show their staff good and bad points and improve their training results.
Therefore, the effectiveness of the technology depends upon the outcomes that are required in each instance, the conditions for operation, together with an understanding by the command team and SUA operator of how they expect the SUA to perform. The technology becomes very much secondary in this equation. Hopefully during future exercises and 'live' operations this approach will become more obvious and will help move the discussion towards a less binary view of operating UAV's in SAR operations.
About the author: Ian Povey is a commercial operator of small unmanned aircraft with a Civil Aviation Authority 'permission' to conduct aerial work. Based in the North of England he is a member of the Civil Air Patrol's Northern Region.