Packing liquids into 100ml bottles is a practice of the past in some airports around the world thanks to the use of CT scanners. Photo / 123rf

For regular travellers, the practice of keeping carry on liquids to 100ml and removing laptops from bags during airport security screening is second nature.

However, in some airports, this inconvenient restriction is becoming a thing of the past.

When Shannon Airport in west Ireland installed new security scanners last October, the news didn't make headlines.

Although, as international travel picks up, their computed tomography (CT) security system has gained attention for what it means for travellers; the ability to carry on liquids over 100ml, and keep them in bags along with electronics when going through security.

The high tech equipment may have cost €2.5 million but means passengers can take "liquids, gels, pastes, lotions and cosmetics in containers of any size through the passenger security point" in cabin baggage.

"Some other airports still only allow liquids in containers of 100ml or less, however with our new security scanning system in Shannon Airport we no longer have this limit requirement with your liquids but they must fit comfortably inside your cabin baggage when fully closed." the airport's website reads.

Shortly afterwards, Donegal Airport also implemented the new technology which allowed it to ditch the 100-ml rule.

Traditionally, airports use 2D x-ray scanners to help identify any potentially dangerous materials in cabin bags.

The CT scanner does the same thing, except with far more precision and detail by creating 3D images. With a CT scanner, the contents of a bag can be examined from a range of angles in a higher resolution before.

In 2018, the superior technology was trialled in major airports like New York JFK, London Heathrow and Schiphol in Amsterdam with success.

Heathrow signed a £50 million deal in 2019 with a CT technology provider, however, passengers are still advised to keep liquids to 100ml and remove them from hand luggage along with electronics during screening.

Amsterdam Schiphol claimed it became "the first major airport to switch to CT scans" in 2021 after installing them in 21 lanes in a departure terminal.

This means passengers can carry more than 100ml of liquids through Amsterdam Schiphol Airport but there is a catch.

"Not all airports have innovative CT scans that are able to check liquids," reads the airport website, following a recommendation to stick to the 100ml rule so they aren't caught out in other destinations.

Herein lies one of the issues; universality.

According to Airports Council International (ACI), an organisation that collaborates with airports, governments, and aviation experts around the world to develop industry-advancing policies and programmes, little will happen quickly without a mandate.

"Regulators are discussing how this could be feasible, however with no current mandate for airports to implement CT on a global basis, relaxing this rule across the board could create too much operational complexity," read a document on CT technology produced by ACI.

"Once more countries are able to complete full nationwide rollouts of the technology, we will start to see more airport and regions start to see the ban being lifted or relaxed - but changes to regulations will not come fast or universally, and it's a changing landscape."

So, can Kiwi travellers look forward to a time when they can carry a perfume bottle or water bottle through security?

In January 2021, the Aviation Security Service (AvSec) released a strategic plan titled 'Horizon 2030', which stated they had "a large screening technology modernisation programme underway."

According to the plan, the programme would include investing in and implementing not just computed tomography (CT) scanners but advanced imaging technology (AIT) body scanners and automated smart lanes as well.

The document did not provide any indication as to when this would happen. An AvSec spokesperson said just getting the technology in the first place was years, not months, away.

"AvSec are actively looking at this (CT) technologies introduction currently, with plans being formulated to introduce it in NZ in future years," they said.

Even then, dropping liquid restrictions, both around volume and type, wasn't a sure thing.

AvSec would 'explore' how the technology could enable it but echoed ACI's stance that regulations would take precedence.

"Final decisions over the removal of such restrictions will be a regulatory decision based on the employment of the equipment by AvSec and the prevailing threat environment at the time," they said.

The Ministry of Transport appeared more confident that CT scanners would not change current restrictions. "The CT scanners may remove the need for some items to be removed from bags for scanning," said a ministry spokesperson, but added this would only be once CAA were "satisfied with the technology and processes involved."

Once satisfied, they said, "the use of CT scanners doesn't change anything around the items that are prohibited, or allow prohibited items onto planes".

Currently, New Zealand's Aviation Security Service states all liquids must be under the 100ml limit. This includes honey, perfume, spreads and toiletries.

At Auckland airport, you can "only carry liquids, aerosols or gels in your hand luggage if each container is no more than 100ml, and these containers collectively can fit comfortably into one re-sealable, 20cm x 20cm (or smaller) transparent plastic bag," according to their website.