Technology is a marvellous thing, but the pace of change can lead to unforeseen challenges. Take 5G deployment. This technology gives mobile device users a massive boost of bandwidth, enabling fibre-like speeds on the go. Yet its introduction in the US almost grounded the civil aviation industry.

It transpired that 5G signals from phone towers close to airfields could interfere with avionic equipment on a lot of airliners – in particular the radio altimeters or radar altimeters that airline pilots depend on to give an accurate altitude reading in reduced visibility. And accurate altitudes are pretty important when it comes to landing aircraft.

While the avionics equipment was certified to operate with 5G signals that are beamed from satellites, it wasn’t certified to work alongside the new ground-based 5G towers, which transmit a concentrated signal across a shorter distance. This was a particular issue for mobile phone masts erected close to airports. When telecoms providers like Verizon and AT&T scheduled the big potential 5G C-Band wireless switch-on for January 19, 2022, unless the towers by the airport were deactivated, these power levels would have caused havoc to aviation safety.

The chief executives of the major US airlines warned that the vast majority of aircraft would essentially be grounded. United predicted delays and cancellations of 15,000 flights a day, and many foreign airlines were starting to pre-emptively take flights off the schedule.

For Cathay Pacific, transpacific routes are among the busiest long-haul routes for our passenger and freighter aircraft. “All of our aircraft are affected to some degree, dependent on how 5G service is implemented at different destinations and the restrictions applied to the aircraft type by the manufacturer,” wrote Captain Mark Hoey, who is also our General Manager Operations, at the time.