I n-flight connectivity (IFC) rapidly is becoming as much of a necessity to everyone on board as ful- ly functioning engines, flight controls, and wheel brakes. It’s a virtual necessity for aircraft flying over the North Atlantic above FL 290, where SatCom connec- tivity is mandated in FANS-1/A airspace. Beyond what’s required for oceanic flight operations, passengers have become so accustomed to Wi-Fi con- nectivity that they may be tempted to cancel a trip if it’s not working. Fortunately, for both pilots and pas- sengers, there are more connectivity options than ever before because of unprecedented demand and market- place competition. Four main characteristics should be considered when determining what system(s) would best fit an operator’s needs: coverage area, connection speed, latency, and price. There are two main routes to in-flight connectivity: air-to-ground and air-to-satellite. Air-to-ground (ATG)
systems—clearly being ground based—provide cover- age above land masses. Their coverage area is limited to line-of-sight visual range between aircraft and trans- ceiver towers on land. Aircraft using air-to-ground sys- tems seldom fly more than 100 nm to 150 nm from the nearest land-based ground station, so there’s less poten- tial latency than when signals must travel between air- craft and satellites in orbit 300 nm to 19,300 nm above the Earth. First-generation air-to-ground systems had data latencies of up to 250 milliseconds, compared to 500-millisecond to two-second lag times for early Sat- Com systems. Air-to-satellite, or SatCom, systems potentially pro- vide coverage over most of the globe but not necessari- ly all areas. Geostationary Earth orbit (GEO) satellites, parked above or nearly above the equator, are among the largest unoccupied space vehicles in orbit. Some have the dimensions of a school bus, weighing 13,000 pounds or more with solar panels that extend 160 feet.
5G cellular networks are revolutionizing air-to-ground connectivity over the continental United States, promising 100 times the speed of third-generation systems and virtually no detectable latency.
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