Small UAS Special Interest Group

contributing to a global set of rules for small Unmanned Aircraft Systems...

Discussion Forum

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Please email me ( joseph.barnard@barnardmicrosystems.com ) your comments and I will paste a copy of your comments on this page, with the most recent contribution at the top.

7th September, 2007

Just something else to put into the melting pot on UAS, regarding the topic of 'Security'…

On the topic of UAV/UAS operations, and perhaps on various aspects of security.

A client required some survey work in some remote part of the world as part of new development. The issue that came up was one of Security for operators (which is aside from operations), and security for the UAV to restrict operation to Authorised Operators should systems be stolen.

The thoughts were/are that both Military and 'Bandits' in that part of the world would like to get hold of technology that was far more advanced than anything that they had, and consideration was that there may be an attempt to remove the equipment! The initial work was then carried out (to great expense) using a satellite mapping service, but requirement is for more detailed surveying to be carried out with our systems in 2008/09.

Is there, should there be, consideration of incorporating into rules/regulations a requirement that operation is immobilized to non-authorised operators?

Neil Key

Aero Technic

I would like to add some comments to those of Dr Rashid (22 June 2007)

UAV Helicopter: Length 1.9m  - Weight 9.8kg (average spec) with avionics and flight control systems, camera mount and controls with high-end spec off the shelf video camera.

Used for general camera surveillance and surveying related to oil/gas pipelines, power cables, rail tracks… in difficult or inhospitable areas.

The effective FAA ban in North America (USA) has curtailed pipeline surveillance projects and ongoing project developments in this region.

Firstly, this is not a 'model helicopter' converted to camera surveillance but a designed airframe to high engineering standards. Powered by Electric or Turbine.

We fly 60 mile missions (average) perhaps with stop-off at point of interest… with potential for pilot override and live video links,  20-40 miles range. The avionics support a number of safety features such as Auto-Land, and Automatic return to base or defined GPS landing position. General flying for observation is at 300-500ft AGL, with positioning flights at 1,000ft.

Re Dr. Rashid's comments on UAS being blind. I think that it would be difficult for commercial aircraft and detection systems to be able to spot this size of aircraft, so a collision detection/warning system would be advisable, and perhaps mandatory.

Having experienced dealing with regulatory bodies for certification of full size aircraft (2-seater kit type helicopters) you need an open cheque if you are working outside the FAA Experimental classification, ie CAA type certification. So some form of engineering standard and flight testing, with build inspection and certification would be a preferred/proposed route.

Again, having experienced the building of large scale models (with possibility of exceeding 20kg - the magic number!) the LMA (Large Model Association in UK) have a system of build inspection and certification, although limited with respect to helicopters.

I would suggest that engineering standards for build and components be considered, a minimum time for flight testing (my own is 20hrs), maximum operating payload for the 'certified airframe', with performance upgrades to be passed off as amendments, etc.

This leads to another of Dr. Rashid's comments regarding "cycles" or service/maintenance schedules. We have our own schedules supplied to clients, and based on working knowledge of the various components, and/or manufacturers stated life. The schedules are in two parts - based on 1) Daily, Weekly, and defined Hours of Operation to be carried out by the Operator (Customer - after training), and 2) Major Service to be carried out by the Manufacturer.

An airframe designed and certified to high standards will stand it's own test of time, and most modern components can be defined for 'life cycles'… such as servos, battery packs, brushless motors. Avionics and systems are more difficult to define, but may be considered as indefinite

When operating relatively small airframes it would also be difficult to duplicate systems and employ redundancy, so the systems and components I employ are generally over specified and lifed at under the recommended operational cycles.

How often for re-certification would depend on use, and therefore a mix of time in service (say 36 months) and operational time in hours. We work to 300 hours for major overhaul of mechanics. This would also depend on any major incident causing significant damage requiring manufacturer repair, and then perhaps a full inspection by Third Party Inspector (re-certification). This would also bring in to being the identification/registration of airframes and components… with many parts being so 'small' it is often difficult place ident tags on all components.

A final point to consider also… is where do such small UAVs fit into the insurance world? This is perhaps the most difficult area of all to define. So Engineering, Design, Methods of Operation, Certification, all need to be geared to the Insurance Market also.

Effectively we are a small operator and whilst maintaining minimum overheads we keep to high engineering standards… something which is difficult to assess with small operations that do not show high visibility offices and high specification machining and build as part of an expensive facility.

Neil Key   BSc Mech Eng

Fax: +44 (0)870 120 8438

I think we have opened up a can of worms.  It is obvious that when considering certification, the intended application will play a crucial role.  For instance, a UAS used by a farmer for crop control, will not need to fly high or far, and most of it would be in visual range, hence need for sense and avoid, or ATM, or transonders may or may not be necessary.  In other applications all of these functions may be totally necessary.  So I go back to my initial thoughts, we must identify all potential application areas, and carefully consider all aspects of operation.

On the issue of sense and avoid, we must not get carried away by it.  Lets face it if i encounter a blind man in my path, then it is up to me to take evasive action.  So why not consider the UAS to be blind? the commercial a/c who can afford the luxury of having powerful radars etc fitted can see and pass on the data of all nearby traffic, so in effect other aircraft can become the eyes in the sky for the smaller UAS.  Data could be transmitted over radio link and the UAS could then take appropriate action.  A UAS could therefore recieve data from other A/C and create a virtual TCAS map.  This would require a good radar cross section, so UAS which are all composite may pose a problem.  I am not suggesting that for this class of UAS we ignore the sense and avoid issue.  I merely want to point out that we have to at least think about a feasible solution that does not rely on elaborate hardware installation on smaller systems.  We have to devise operational strategies that do not compromise safety or security, and yet allow the UAS to fulfill its mission requirements in the most ecconomical manner.

On another unrelated issue.  After how many cycles would we consider the UAS to become unsafe?

How often would we expect it to be recertified?.

And to all of you out there.....for the flame to stay lit, we need a lot of fuel.  So please post your comments.

Rashid

Dr. Rashid Ali

Senior Lecturer (Avionics and Aerospace Systems) Aerospace, Automotive and Design Engineering University of Hertfordshire College Lane Campus Hatfield AL10 9AB United Kingdom

Tel office : +44-1707-281039

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