Heathrow’s T5 says goodbye to old-style baggage scanners

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Heathrow Terminal 5 has removed its last outdated baggage scanner, marking a switchover to 3D scanning for all hold baggage.

Heathrow Terminal 5 – which handles 32 million passengers a year – has completed the largest update to its baggage handling system since the terminal opened in 2008, replacing its 29 hold baggage screening machines with new machines enabling 3D scanning.

Terminal 5 has now shut down and removed the last outdated hold baggage scanner, marking the completion of the switchover.

The baggage system at Terminal 5 is almost entirely automated. Once a label with a barcode has been attached to a hold suitcase, it is loaded onto a conveyer belt and travels through an intricate baggage handling system hidden beneath the familiar passenger-facing frontage of the airport. Every single piece of hold baggage must be scanned for suspicious items, much like every passenger and their cabin luggage is scanned. The Terminal manages approximately 30,000 bags a day – even more during holiday seasons – sending the bags on to various airlines running dozens of different international flights and connections.

“From when the bag goes into the system to when it comes out at the other end, it’s not really touched by human hands,” said Darryl Grinter, who managed the now-completed baggage changeover project. “It needs to be very efficient and do it all in a way in which the bag is totally 100 per cent secure.

“People travel with everything and anything and this system has to cater for all those things; every one of those bags is really personal. It’s not just about ‘stuff’ going through a conveyer system […] When these sorts of systems go wrong, you see it in the news.”

The new baggage scanners work much like CT scanners; an x-ray tube rotates around the body of the machine, emitting beams which are partially absorbed by the items in each suitcase and picked up by detectors. This data is used to create 2D images of ‘slices’ of the baggage. Many 2D images are combined to form a detailed 3D image of the baggage which can be viewed from any angle. While the hardware has much in common with CT scanners found in hospitals, the software is distinctly different, Grinter explained. The secretive process for identifying potentially dangerous objects, for example, combines automated image recognition and human decision-making.

In order to shield workers from the powerful radiation inside the scanners, the scanners contain multiple layers of lead slabs, including lead ‘curtains’ at entrance and exit which absorb the x-rays. The new machines are roughly twice as heavy as their predecessors, weighing over seven tonnes.

The process of replacing the old baggage scanners fitted deep inside Heathrow’s guts with the hefty new machines was a feat of engineering described as “keyhole surgery” on the live baggage system, which had not been built to accommodate scanners with these specs. Each replacement took 12 weeks from start to finish, with much of the practical work limited to a small window in the middle of each night in order to prevent disruption to passengers. Engineers created a digital twin (computer simulation) of the entire system to ensure that it would continue to run sufficiently while the works were being carried out, even under challenging circumstances.

Debbie Dore, CEO of the Association for Project Managers (APM), which worked with Heathrow staff through the upgrade, commented: “Overcoming technology and logistics challenges for this project were just part of the story for the Heathrow team; they worked hard to factor in third party involvement and significant infrastructure hurdles.”

Replacing the scanners was not simply a matter of taking the old machine out and putting the new one in, while new baggage management lines had to be set up to continue operations while a machine was out of service and the old infrastructure had to be updated to support the 3D scanners. For instance, some floors underneath the old scanners had to be reinforced bit by bit in order to support the weight of the new scanners, while some other floors had to be removed in order to lift the scanners into place. Engineers, managers and technicians celebrated each new machine entering service with a bell-ringing ceremony, culminating with a gong-ringing for the final machine.

Every change to the baggage system required changes to be made to the higher-level systems which track luggage from check-in to exit.

Criteria laid out by the Department for Transport required all British airports to complete the switchover by 1 April 2019; Heathrow Terminal 5 finished installing its new scanners 35 days ahead of the deadline. According to Grinter, if the deadline had not been met, the old machines would be forced to shut down and “this would have brought the Terminal to a halt.”

Last week, Prime Minister Boris Johnson announced that airports would be required to roll out similar 3D scanners for cabin baggage by 2022. This will present airport operators with considerable engineering challenges, but could cut the amount of time required for security screening and put an end to the much-derided safety precautions of bans on liquid containers above 100ml and the demands made of passengers to temporarily remove their shoes and any heavy items of clothing.

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