PARIS-LE BOURGET AIRPORT MAINTENANCE
Airport maintenance tasks have always been crucial to insure complete safety in the airport for both passengers and operators. Aeronautical standards necessitates very reliable systems to operate and it inevitably requires a secured and efficient maintenance deployment. Time and safety are 2 key vital elements fully matching with tethered drone solutions deployed for airport maintenance tasks.
PARIS AIRPORT MAINTENANCE
The Groupe ADP is the French airport authority which builds and manages airport platforms among which Paris-Charles de Gaulle, Paris-Orly and Paris-Le Bourget. In 2016, Paris Aéroport has welcome more than 97 million passengers in Paris-Charles de Gaulle and Paris-Orly, 2.2 million tons of freight and mail and more than 42 million passengers through abroad airports thanks to its subsidiary ADP Management. Paris-Le Bourget remains the leading business airport in Europe.
PAPI: Precision Approach Path Indicator
Many lights cover the runways of airports to help pilots land and navigate safely. One of them is the PAPI: Precision Approach Path indicator. Created in 1974, the PAPI primarily provides visual glide slope guidance to pilots in non-precision approaches environment. Located beside the runway, this instrument has an effective visual range up to 3 miles during the day and up to 20 miles at night.
While landing, pilots can determine if their approach is too high, too low or on the right slope thanks to the red and white light indicators. For a correct approach, the pilot must observe 2 red and 2 white lights. From 3 white lights and more, it indicates that the aircraft is too high. On the other hand, 3 red lights and more indicates that the aircraft approach is dangerously too low.
To maintain operational conditions and precision of the PAPI, projected maintenance is carried-on using for instance flying machines or elevating work platforms. Blocking off the access to the runway, PAPIs checking is made by simulating sinusoidal approaches to verify threshold angles and ensure compliance with regulations. On the down side, the airport necessarily shuts down the runway, consuming up-time, imposing complicated logistics and taking risks by deploying operators in the air and on the runways.
SOLUTION AND PROCESS
For achieving this aeronautical maintenance task, Groupe ADP deployed the Elistair tethered drone solution: the Safe-T station. Tethering an hexacopter carrying an X18 optical zoom handy-cam digital camera, this configuration permits an easy, safe and fast deployment within the airport.
Allowing a precise high-view point over the Paris-Le Bourget runways, the tethered drone has also been equipped with a vertical laser module in order to increase the precision of its geo-localization while performing the PAPI checking. Necessitating 2 operators on the ground, the solution is simple and secured by the umbilicus cable specifically built for resisting to high traction while supplying the drone in power and transferring high-speed data.
Using a flying tethered drone, inspections of PAPIs are much easier to carry-on. As flying tethered allows long stationary flights, the tethered drone can easily detect the precise pass through each different threshold indicators: mixing the white and red colours, the observation results in a pink threshold point as seen on the opposite illustration. To provide more robust precision in the PAPI checking, the tethered drone is deployed at 2 minimum distances. Knowing the required PAPI threshold angle αA and by basic trigonometry calculation, this angle can be verified by monitoring the precise altitude of the pink threshold detected, and at the 2 distances d1 and d2 (see the opposite illustration).
Using the Safe-T micro-tether station, the Elistair drone flies in a controlled volume from 50m to 100m radius. Plus, by transferring the video through the micro-tether, data does not suffer from interferences. When checking the furthest distances, the camera can zoom on the PAPI and defocuses: the way the lens renders out-of-focus the PAPI lights appears in a bigger and colourful diamond shape.
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