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Chapter 10. Detect and Avoid (DAA) 10-11 Special considerations for low-level flights
10.13.4 Many RPA will be employed in low-level operations, putting the aircraft in close proximity to terrain and obstacles. The DAA capability will need to account for this type of operation.
10.13.5 The appropriate State authority will need to be satisfied that, based upon the DAA capability, the proposed low level operations can be conducted safely.
10.13.6 If terrain and obstacle avoidance is automated, the avoidance manoeuvre is performed by default (human- on-the-loop). However, it should have an abort/inhibit capability for the remote pilot. Remote pilot intervention to abort/inhibit the manoeuvre would only be expected in the rare event that the remote pilot has sufficient information to conclude that allowing the automated manoeuvre to occur would be more hazardous than aborting it.
Database considerations
10.13.7 It is expected that the current databases related to terrain and obstacles for manned aviation may not have the right level of detail for very low-level operations.
10.13.8 If terrain and obstacle data to support RPA flight operations below IFR altitudes are required, changes or additions to the existing terrain and obstacle databases may be needed. Any such database changes should be designed in accordance with public standards such as RTCA DO-200A — Standards for Processing Aeronautical Data and EUROCAE ED-76 — Standards for Processing Aeronautical Data.
10.14 MITIGATING THE RISK OF HAZARDOUS METEOROLOGICAL CONDITIONS
10.14.1 All aircraft are affected by meteorological conditions. In manned aviation, the pilot is able to monitor changes to the conditions visually and through use of sensors and the display of their information. Remote pilots conducting BVLOS operations must rely to a far greater extent on sensors and the display of sensor information.
Considerations for DAA capability for hazardous meteorological conditions
10.14.2 Remote pilots may be able to combine DAA information from the detection of hazardous meteorological conditions with information from other systems (e.g. ambient air temperature, winds from navigation systems, forecasts) to take action to avoid meteorological hazards such as icing, wind shear or turbulence.
10.14.3 Remote pilots should consider the effects of meteorological conditions along the flight path, in order to avoid or be aware of possible interference with the C2 link.
10.14.4 DAA capability needs to be related to the RPA operational flight envelope and any hazardous meteorological limitations associated with the RPA, especially in regard to icing and turbulence. If the RPA is not capable of flight in icing conditions for example, then the detection capability must be appropriately sensitive to alert the remote pilot to any indication of potential icing conditions with an appropriate sense of urgency.
10.14.5 A DAA system for hazardous meteorological conditions may not be needed if the RPA flies IFR routes and altitudes based on forecast and reported conditions where the likelihood of encountering hazardous meteorological conditions is below an acceptable level. For example, if an RPA flies for a relatively short duration in an area where no turbulence, icing or thunderstorms are forecast or reported, then operation of a DAA system for these conditions may not be required.
10-12 Manual on Remotely Piloted Aircraft Systems (RPAS) 10.15 MITIGATING THE RISK OF COLLISION DURING GROUND OPERATIONS
10.15.1 Ground operations involve all aspects of aircraft handling on the airport surface as well as aircraft movement on the aerodrome including on active runways.
10.15.2 The remote pilot needs to be able to DAA potential hazards on the surface, identify applicable aerodrome markings (e.g. runway hold lines) and be able to follow ATC instructions in order to mitigate the risk of collision with other aircraft, ground vehicles or obstructions.
10.15.3 DAA systems on the RPA to assist the pilot in avoiding collisions on the ground may not be needed if special ground handling procedures, such as towing the RPA to the end of the runway/launch point or controlling the aircraft taxi to the same point from a position in close proximity to the RPA, are used.
10.15.4 RPA observers may be necessary as a mitigation to overcome any safety concerns for initial operation of DAA systems on the ground.
10.16 MITIGATING THE RISK OF OTHER AIRBORNE HAZARDS
10.16.1 Other hazards which may be encountered by RPA include, but are not limited to, wake turbulence, wind shear, birds and volcanic ash.
10.16.2 RPAS may be able to leverage standards development efforts for manned aircraft systems with respect to wake turbulence applications. RTCA has defined a concept of operations for transmitting aircraft-derived meteorological data to enable applications for wake turbulence to support next generation air transportation system (NextGen) and single European sky ATM research (SESAR) initiatives. Standards development work to support specific airborne wake turbulence applications needs to consider RPAS requirements in addition to other aircraft.
10.16.3 Annex 2, 3.2.1, requires an aircraft to “keep out of the way of another” per right-of-way rules and “avoid passing over, under or in front of the other, unless it passes well clear and takes into account the effect of wake turbulence”. DAA for conflicting traffic will need to consider aircraft wake turbulence in conducting well clear manoeuvres with respect to right-of-way rules that also account for wake turbulence.
10.16.4 RPAS designed to allow RPA to conduct approaches in a manner similar to current visual approaches may need to include DAA to address wake turbulence. The safety and efficiency of visual approach operations relies on the PIC’s ability to accept responsibility for “ensuring that the spacing from a preceding aircraft of a heavier wake category is acceptable” in accordance with Doc 4444, 5.9. The PIC of an RPA may need DAA for wake turbulence to efficiently integrate RPA arrivals with other aircraft when visual approach operations are being conducted.
10.16.5 The RPA may need a DAA system to detect other airborne hazards such as wind shear, birds or volcanic ash if exposure to them will place the safe continuation of the flight in jeopardy. DAA for volcanic ash exposure may not be needed if RPA flight is restricted to remain away from areas of forecast or reported ash. In a similar manner, a DAA system for wind shear or birds may not be required if the RPA flight is planned and executed to remain clear of these hazards or if the flight control and performance of the RPA allows recovery of safe flight continuation or termination after exposure to these hazards.
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