Transport Secretary Pete Buttigieg said on Tuesday that airlines were told the 1 July deadline would remain in place.

Airlines have warned that they will not be able to meet the deadline and may be forced to ground some planes.

Telecoms firms have previously delayed 5G rollout to allow airlines to adapt.

In the US, the radio frequencies being used for 5G are in part of the spectrum known as C-Band.

The Federal Aviation Administration (FAA) and aviation companies have previously raised concerns that C-Band spectrum 5G wireless could interfere with aircraft altimeters, which measure a plane’s height above the ground.

In a call with airline companies on Tuesday, Mr Buttigieg told them to work aggressively to retrofit their planes before the deadline, according to the Reuters news agency.

Concerns about 5G interference led to some disruptions at US airports last year.

Major tech companies, like Verizon and AT&T, agreed last year to delay the rollout of 5G technology until 1 July 2023 to allow airlines time to retrofit their altimeters.

The decision came after several previous delays.

The International Air Transport Association (IATA), a trade group representing more than 100 airlines that fly in and out of the US, has said the decision not to extend the deadline makes summer disruptions more likely.

“Supply chain issues make it unlikely that all aircraft can be upgraded by the 1 July deadline, threatening operational disruptions during the peak northern summer travel season,” the organisation said on Tuesday, adding that the estimated cost to upgrade planes is $638m (£511m).

“Airlines did not create this situation. They are victims of poor government planning and coordination,” said Nick Careen from the IATA.

Airlines have previously said they want 5G signals to be excluded from “the approximate two miles of airport runways at affected airports as defined by the FAA”.

Phone companies have spent tens of billions of dollars upgrading their networks to deploy the 5G technology, which they say brings much faster internet services and greater connectivity.

Technology companies have said 5G is safe and have accused the aviation industry of fearmongering and distorting facts.

In the EU, networks operate at lower frequencies than those which US providers are planning to use – reducing the risk of interference. 5G masts can also operate at lower power.

Nevertheless, some countries have taken further steps to reduce possible risks.

In France, there are so-called “buffer zones” around airports where 5G signals are restricted, while antennas have to be tilted downwards to prevent potential interference.

The UK’s Civil Aviation Authority (CAA) has said “there have been no confirmed instances where 5G interference has resulted in aircraft system malfunction or unexpected behaviour”.

But it has stressed that “different national mobile telecommunication strategies may mean that some [countries] have a higher threat exposure than others”.

In a separate development, the FAA on Tuesday proposed new rules for many Boeing aircraft due to the possibility of new 5G interference

The proposed rules affect nearly 20,000 planes worldwide. They require revised flight manuals, bans on some landings, and new operating procedures for landings and approaches when dealing with 5G interference.

A representative for Boeing told Reuters that the company “continues to work with suppliers, regulators, the airlines and telecom companies to ensure long-term stability and help mitigate operational restrictions where possible”. (BBC)

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