Stationary vs rotating gantry: protecting your new EDS baggage screening system against obsolescence

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John Percival, president of SureScan, presents the case for investing in fixed gantry, rather than rotating gantry, EDS baggage screening systems

With many different models and capabilities of Standard 3 (or TSA 7.2) screening machines available on the market, it can be very difficult to determine what machine and what technology to use when considering the purchase of new screening machines.

This is doubly important due to the high cost value associated with these machines and the future operation and maintenance (O&M) requirements. Compounding this decision-making process is the different interpretations on a national level of the Standard 3 Screening processes, which significantly change the baggage flows of the traditional Standard 2 process.

In addition, though advancements in capacity have been significant for several of the Standard 3 screening machine platforms, many of the machines on the market lack the capability of sustained high-speed throughput (more than 1,500 bags per hour with less than 15% reject rate over the course of more than two hours).

There are currently seven major suppliers of hold baggage screening equipment. These are L3, Morpho, Nuctech, Rapiscan, Reveal, Smiths and SureScan. With the current ongoing merger of Smiths and Morpho, this number will be eventually reduced to six. Each of these companies offers equipment that has been tested in the field and all have had varying degrees of success with their Standard 3 machine concepts. The differentiators between each are relatively substantial as each of the machines provided by these suppliers have their own strengths and weaknesses due to the approach that was taken during the development process. However, the machines can be organized into two major machine groups: stationary gantry (sometimes referred to as fixed gantry), and rotating gantry. The difference between a stationary gantry machine and a rotating gantry machine is the method by which the computer tomography (CT) scanners are utilized.

The original EDS machine technologies focused on a rotating gantry as this was the technology that was initially developed for the medical industry in the 80s and 90s. As the name implies, in a rotating gantry machine, the detectors rotate at high speeds around a central belt. The benefit for this older technology is that these machines provide fairly high image quality though at low speeds. The problem with these machines is that as throughput increases, the rotational speed must also increase. This causes heavy vibration, increasing sound volume, higher potential for loss of tracking and most importantly extremely high maintenance costs due to the constant wear and tear on the internal moving parts.

The newer stationary gantry machines no longer require rotating mechanisms to provide the required 3D images that are needed for the current international requirements. These machines are generally much quieter due to limited vibration, as there are no major moving parts. In addition, these machines provide much higher upgrade and automated evaluation capabilities compared to rotating gantry units. Due to the more advanced technology implemented in stationary gantry solutions, the capability of the machines to automatically detect threats is much higher than rotating gantry solutions. The advantage of this technology is demonstrated by the fact that the SureScan x1000 is currently the only EDS to have passed the ECAC Standard 3.1 requirements.

Within the above major differences between stationary and rotating gantry systems is also the cost of operation and maintenance and spare parts, which make up the total cost of ownership calculation for the machines. Generally, due to the reduced number of moving parts, the stationary gantry solutions are less expensive in the longer term. Though generally feasible with lower volume systems, rotating gantry solutions also have the possibility of being technologically out of date in the next 10 years and are likely to require at least one complete change in the entire gantry over that period (which means high cost). With stationary gantry solutions, the individual scanners may also need to be replaced (or reconditioned) at least once within a 10-year window, though the cost of this replacement will be normally much lower than their rotating gantry counter-parts.

In conclusion, the key attribute that an airport should consider in the evaluation of screening machines is their technical capability over a longer period of time. This should also take into consideration the needs of the airport and its growth plan. Though stationary gantry solutions appear to provide a better value for cost, in certain cases the utilization of a rotating gantry may be strongly considered by an airport if these are provided at substantially reduced up-front costs. However, the airport client should be aware of the operational costs of these machines and their actual future capabilities when increasing capacity speeds and increasing minimum bag lengths render these machines increasingly obsolete.


As president of SureScan Corporation, John Percival is responsible for SureScan operations, manufacture, service and sale of SureScan machines. Through Percival’s leadership, SureScan has seen a rapid transition over the past two years from prototype manufacturing to volume production, deployment and installation, further positioning SureScan as a leading supplier in the global marketplace.

Prior to joining SureScan, Percival was vice president – engineering and manufacturing, Brooks Life Sciences; vice president – engineering and managing director, Analogic Corporation; vice president and general manager, CT Medical Systems; as well as senior director of CT research and development, Philips Medical Systems.

August 4, 2017

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