Seven airports will have to install CT X-Ray machines by end of this year

Mumbai International Airport

On Saturday, the Times of India reported that the Bureau of Civil Aviation Security (BCAS) has asked big airports to install full body scanners and X-ray Computed Tomography (CTX) machines by December 31, 2023. The report states that airports which handle over 50 lakh passengers annually have been asked to install these machines.

What is CT X-ray?

X-ray Computed Tomography (CT) machines are a non-destructive technique for visualising interior features within solid objects, and for obtaining digital information on their 3-D geometries and properties.

The images are sliced into smaller ones, corresponding to a specific thickness. While a typical digital image is composed of pixels (picture elements), a CT slice image is composed of voxels (volume elements).  A complete volumetric representation of an object is obtained by acquiring a contiguous set of CT slices.

The grey levels in a CT slice image correspond to X-ray attenuation, which reflects the proportion of X-rays scattered or absorbed as they pass through each voxel. X-ray attenuation is primarily a function of X-ray energy and the density and composition of the material being imaged.

A CT scanner uses all of this data to create a very detailed tomogram (slice) of the bag. The scanner is able to calculate the mass and density of individual objects in your bag, based on this tomogram. If an object's mass/density falls within the range of a dangerous material, the CT scanner warns the operator of a potential hazardous object.

How does it help?

The current scanning system at airports in India requires passengers to remove all liquids, charging devices, electronic devices, among others. The new technology has the ability to scan them for safety and security risks while being inside the bag. While a few airports have now installed ATRS (Automatic Tray Retrieval System), there is still congestion at the point where passengers have to remove certain items from their bags and place them on trays.

The ability to put the bag in the CT X-RAY based scanner will ensure that passengers don't queue up to remove medicines, other liquids, and electronic devices, among others.

Full-body scanners

Full-body scanners require passengers to stand inside a scanner till an image is taken, unlike passing through a Door Frame Metal Detector (DFMD) as is the case right now.

If the full-body scanner does not show any anomaly, a person is not checked further, unlike the current system where the officer also does a check with a Hand Held Metal Detector (HHMD), and, in some cases, a pat-down search.

India has seen trials of full-body scanners in the past, but, at multiple times, the final installation was stopped. Initially, passengers were apprehensive of the images from the scanner and the BCAS, too, had its concerns on the blank spots from these machines.

Full-body scanners are slowly making a beeline at airports globally.

Why the need?

Airports have been at the receiving end, especially on social media, for the slow passage at the security check and other bottlenecks. Sadly, while airports face the flak, these bottlenecks are not under the control of airport operators.

Entry, security, and immigration and customs (for international) are handled by officers deputed from central government agencies and a lack of staff impacts airports adversely.

As India aims to be a global hub and Indian carriers expand, both domestically and internationally, airport throughput is a challenge and these modern technologies will help speed up security checks with the same manpower, since the Central Industrial Security Force (CISF), which ensures security at major airports, is also short-staffed.

Which airports will have to install the new machines and full body scanners?

The report says that airports with over 50 lakh passengers will have to install the new X-ray machines. Last financial year, there were seven airports which crossed a footfall of 1 crore passengers. Footfall includes both arriving and departing passengers. While the split is not always 50 percent each between arriving and departing passengers, it is safe to assume that these airports will be the ones which will be the first to shift.

Airports with 1 crore footfalls - FY 22-23

Any additional capital expenditure now will likely require the passengers to shell out higher PSF at these airports in future.

If the machines and processes work as intended, passengers may rejoice. Else, photos of long queues and snarling bottlenecks on social media will be the result.