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Airbus explains safe landings with modern satellite-based 3D precision systems

Modern commercial aircraft and helicopters have the ability to operate safely at airports and heliports with 3D precision, regardless of ground infrastructure. This is possible thanks to Global Navigation Satellite Systems, which can provide pilots with their vertical and horizontal (lateral) GPS position augmented with the SBAS (Satellite Based Augmentation System) position during landing approaches. Given this, Airbus presents some basic explanations, but quite interesting about the operation of these systems. Like fixed-wing pilots, helicopter pilots often have to deal with weather and terrain-related challenges in their operations. To address this, a form of GPS technology now allows for the design of specific approach and departure procedures known as Point-in-Space (PinS). These helicopter-specific procedures include a visual segment when near the airport or helipad, as well as a Visual Flight Rules (VFR) segment or an Instrument Flight Rules (IFR) segment when farther from the airport or heliport. PinS also takes advantage of the low-speed handling capabilities of a helicopter. A major advantage of PinS technology is that it provides accurate horizontal and vertical guidance in “controlled” or “uncontrolled” airspace and regardless of the local heliport ground infrastructure, thanks to enhanced GPS with SBAS. This greatly increases accessibility to heliports surrounded by buildings or land, for example. In addition, being an “IFR” procedure, PinS results in fewer flight interruptions, while offering a greater degree of safety during approaches and takeoffs in degraded visual conditions. The same satellite constellations – collectively known as Global Navigation Satellite Systems (GNSS) – being used by the PinS described above, also allow for 3D satellite-guided landing approaches (i.e. with horizontal orientation and vertical) for airlines and general aviation operators flying fixed-wing aircraft of all sizes. For its part, Airbus has progressively introduced a new cockpit function called the Satellite Landing System (SLS), which allows pilots to perform precise approaches at airports without the need for additional ground-based systems such as an Instrument Landing System (ILS). SLS also means that equipped aircraft do not need to rely on their own barometric altimeters (which are based on air pressure) as the basis for their glide slope prediction. This is possible because the SLS improves the accuracy and reliability of the GPS information thanks to the overlay corrections that the aircraft receives from the SBAS. These corrections allow a vertical orientation of the aircraft based on the geometric altitude. Like PinS technology for helicopters, SLS is beneficial for commercial fixed-wing aircraft when operating at airports that are not equipped with ILS guidance and especially in conditions of low visibility and/or with surrounding terrain or other obstacles. The SLS first entered service in Europe with the A350 in 2014 and is now also available on the A220, A320, A330, and A380 families, similar in accuracy and pilot interaction as the current ILS. In terms of accuracy, the SLS is similar to the traditional terrestrial ILS system, although for now the SLS can guide the aircraft to what we call “CAT1” – that is, 200 feet (61 meters) above the ground, from where the pilot can usually see the runway. Also, for many secondary airports without ILS, pilots in earlier times would not be able to land there in lower visibility conditions, and would need to divert to an alternate airport with better visibility. Now, with the SLS, they can safely continue to their originally intended destination – even if the weather turns bad, as long as pilots can see the runway when they reach the 200-foot minimums. Additionally, since the design of the SLS function is fully integrated into the cockpit display architecture, it was possible to make it very pilot friendly. The result is that with SLS pilots do not need to change the way they fly the aircraft because the orientation symbology presented in the cockpit, in the Primary Flight Display (“PFD”), is exactly the same as what they already are used to an ILS approach. – https://aeroin.net/airbus-explica-a-seguranca-dos-pousos-com-os-modernos-sistemas-de-precisao-3d-baseados-em-satelite/