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Newsflash from ALPA International

ALPA Security Alert 2010-04
November 12, 2010
SUBJECT: Advanced Imaging Technology Equipment and Procedures


ALPA’s president, Capt. John Prater, has had numerous high-level discussions with DHS Secretary Janet Napolitano and TSA Administrator John Pistole over the past several days concerning the issue of security screening and has made specific, confidential recommendations on how it should be addressed. The Association’s concerns have been heard and are being examined by the Administration with the goal of finding acceptable solutions.

ALPA has urged the U.S. Government to cease subjecting flight crewmembers to AIT screening protocols immediately. We are seeking near-term and long-term relief for pilots from traditional checkpoint screening requirements because we believe them to be unnecessary and ineffective as applied to flight crews. ALPA’s highest security priority is an effective means of screening and access to airport sterile areas commensurate with a pilot’s trustworthiness and responsibilities. This document has been prepared to assist you in transiting the screening checkpoint until ALPA is successful in obtaining an effective and appropriate security checkpoint methodology befitting airline pilots.

Due to the recent deployment of Advanced Imaging Technology (AIT) at many airport checkpoints, ALPA’s National Security Committee (NSC) and the Association’s Aeromedical Committee and Aeromedical Office have collaborated to provide ALPA members with specific information regarding the science, potential health impacts and security protocols associated with AIT.

In March 2010, the TSA began deploying 450 AIT units in airports nationwide, with an announced goal of deploying nearly 1,000 AIT machines by the end of calendar year 2011. AIT is designed to screen for both metallic and non-metallic threats, including weapons and explosives, without direct, physical contact.

Two different AIT technologies are in use at airports across the nation: millimeter wave and backscatter x-ray. TSA describes those systems as follows:

  • Millimeter Wave AIT – Millimeter wave AIT uses non-ionizing radio frequency energy in the millimeter wave spectrum to generate a three-dimensional image of the body based on the energy reflected from the body. The image, which resembles a fuzzy photo negative with facial features blurred for privacy, is displayed on a remote monitor for analysis to determine whether potential threats are present.

  • Backscatter X-ray AIT – Backscatter AIT uses a narrow, low-energy x-ray beam that scans the surface of the body at a high speed. The machine then generates an image resembling a chalk etching with a privacy filter applied to the entire body. The image is displayed on a remote monitor for analysis to determine whether objects are present.

TSA Views on AIT Health and Safety Issues

The TSA has declared AIT to be safe for all travelers. According to its research, energy emitted by millimeter wave technology is thousands of times less than what a cell phone is allowed to emit. TSA also has stated that the amount of radiation from a backscatter scan is equivalent to two minutes of flight on an airplane. On its website, (, TSA states, “Naturally occurring ionizing radiation is all around us. We are continuously exposed to this background radiation. In 17 minutes of ordinary living, a person receives more radiation from naturally occurring sources than from one scan.”

TSA Perspective on AIT Privacy Issues

TSA states that it has implemented numerous measures to protect passenger privacy, including:

  • Signage which informs passengers of privacy considerations

  • Has made AIT screening optional

  • Image officers are remotely located and do not see the individual whose image they view

  • Faces on AIT images are obscured by filters

  • Images cannot be saved, transmitted, printed or otherwise stored

More about TSA’s views on privacy are provided on its website at

ALPA Views on AIT Health and Safety Issues

ALPA’s Aeromedical Committee earlier this year published a bulletin (i.e., the March/April 2010 Aeromedical Flyer) on the potential health and safety effects of AIT equipment as relates to airline pilots, who face repeated exposures.

Two excerpts from the Aeromedical Flyer, the first on back-scatter x-ray and the second on millimeter wave technology, are provided herewith:

Back-scatter x-ray

To calculate the maximum number of backscatter X-ray scans that a flight crewmember could receive that would result in the maximum annual occupational exposure limit, one would take the difference between the highest estimated exposure from in-flight radiation exposure and the maximum recommended exposure for occupationally exposed individuals. The resulting difference is 10.9 millisieverts per year. In order for a crewmember to receive 10.9 millisieverts of radiation from backscatter X-ray scans, he or she would have to be subjected to 218,000 scans per year, which equates to an average of 699 scans per day (calculated over a 6-day work week, 52 weeks per year). Given the number of scans that would be required to reach this limit, it is a safe assumption that this limit is unachievable even by the most active crewmember. While these limits apply to occupationally exposed individuals, one needs to keep in mind that limits for occupational workers who are pregnant are subject to different recommendations. Current recommendation set forth by the ICRP for pregnant workers is 1 millisievert over the course of a pregnancy. Given these limits, full body scans could pose different challenges for pregnant crewmembers, which is beyond the scope of this article.

Millimeter wave

Millimeter wave technology creates a three-dimensional image of the body, revealing concealed objects beneath clothing. Electromagnetic radiation in the high radio frequency (terahertz) band is transmitted simultaneously by two coils or antennas which rotate around the body during the scan procedure. Although the technology employs electromagnetic radiation, the type of radiation associated with this scan is classified as non-ionizing radiation. The electromagnetic wave that is reflected from the body surface is processed to form a three-dimensional image of the body surface. While the electromagnetic radiation is not considered ionizing, researchers are currently investigating the health effects of terahertz radiation exposure. The American College of Radiology (ACR) released a position statement in January 2010, citing that the technologies associated with both scanning modalities is not considered to present significant biological effects for passengers screened. Results from research conducted at Los Alamos National Laboratory suggests that terahertz radiation exposure may affect DNA dynamics, impacting processes associated with gene expression and DNA replication. Current position statements by national organizations suggest that the risk associated with such scans may not significantly increase risk to adverse health effects. Further research may be warranted to investigate the proposed risk suggested in preliminary studies, especially given that debate still exists over the safety of this form of imaging technology.

Dr. Quay Snyder, ALPA’s Aeromedical Advisor, makes the following statements regarding repeated AIT exposures for pilots:

ALPA’s Aeromedical Committee is actively studying TSA’s Advanced Imaging Technology (AIT) and its potential effects on pilots who face repeated exposures. The March/April 2010 Aeromedical Flyer offers an excellent synopsis of the current science and relative risks associated with this technology. The equipment used in AIT meets scientific recommendations for radiation exposure for the general public even when considering the multiple exposures pilots face over a career. The backscatter screening technology provides a very small contribution to a pilot’s annual total ionizing radiation dose. Although the science on very low dose radiation exposure has not shown a causal relationship with cancer or other diseases, no amount of ionizing radiation should be considered completely safe in the absence of scientific evidence. Pilots should minimize their exposures to ionizing radiation in both non-occupational and occupational settings.

Millimeter wave AIT does not utilize ionizing radiation as does the backscatter technique, which has been shown to pose a health risk in moderate to high dosages. The millimeter wave technology uses electromagnetic radiation, which is under study and the subject of debates similar to those related to questions whether cell phones potentially cause brain tumors or living near a high power line causes birth defects and other diseases. No evidence exists, but the issue is still under study.

TSA Policy On the Use of AIT and Pat-down Procedures

An individual who presents himself or herself for checkpoint screening will be directed by a Transportation Security Officer (TSO) to pass through either a walk-through metal detector (WTMD) or an AIT portal. TSA policy permits individuals to refuse to be screened by any technology deployed at airport checkpoints, including the AIT, WTMD and baggage x-ray for carry-on luggage, and request a private physical screening. An individual who refuses to be screened by a particular technology does not have the right to choose an alternative, preferred technology.

If an individual refuses to use a particular checkpoint screening technology such as WTMD or AIT, the TSA will use standard pat-down procedures by a same sex-screener as the primary method of search (as opposed to a hand-wand search). Standard pat-downs are conducted with the palm of a screener’s hand, except for more sensitive areas of the body (i.e., groin or breasts), where the back of the hand is used. During any alarm resolution, resolution pat-down searches may include a more aggressive touching of the individual’s body in the suspect area with the palms of the hand, except for the groin and breast areas, which will be conducted with the back of the screener’s hand. Following any pat-down search, the hands of the TSO will be tested for residue by explosive trace detection (ETD) equipment.

An individual can be subjected to checkpoint pat-down search for a number of reasons:

  • Opting not to submit to AIT or WTMD

  • An unresolved alarm after submitting to either AIT or WTMD

  • Random selection

  • Designation as a “selectee”

Withdrawal from Screening Process

According to TSA, once an individual presents himself or herself for airport checkpoint screening (i.e., submits to the process of an administrative search), he or she cannot withdraw from the process before its completion without risk of exposure to a TSA investigative process and/or local law enforcement action. The agency cites U.S. v. Aukai, U.S. Court of Appeals, 9th circuit, 2007.


The TSA does not currently differentiate between passengers and crewmembers regarding the use of AIT at airport checkpoints. ALPA categorically objects to this policy and is currently engaging government policy makers to bring short-term and long-term relief from this process to all flight crewmembers.

As we pursue that effort, we offer our membership the following guidance:

  • TSA permits you to opt out of AIT screening. If you do so, you will be required to submit to a pat-down screening which you may find invasive of your privacy.

  • Maintain a professional demeanor at all times, as your actions are on public display and are likely being video-recorded

  • If selected for pat-down screening, request a private search. Note: ALPA has made an inquiry of the TSA to determine if they will permit a pilot to have a witness with them during pat-down searches. The answer to that question will be relayed to the membership upon receipt.

  • If you encounter suspected unprofessional and/or inappropriate behavior by checkpoint screeners, file reports with the TSA checkpoint supervisor, your chief pilot’s office, and your MEC Security Committee Chairman/Coordinator

  • Be aware that your Ground Security Coordinator will not be able to aid you in resolving difficulties at the screening checkpoint

  • Be advised that the National Security Committee is updating and will soon publish a revised Jepp-sized brochure with more detailed information on transiting the screening checkpoint.

This document obviously does not address every question that may be raised about security screening, but the National Security Committee will continue to update the membership with answers to questions on this important subject as appropriate. We thank you for your patience and professionalism as we strive to create a better security screening environment for all airline pilots.


Captain John Prater Captain Robert Powers
President Chairman, National Security Committee

ALPA successfully developed CrewPASS to electronically verify airline pilot identity and employment status. The Association has been working for more than two years with TSA and other industry stakeholders to promote its implementation, but a lack of funding has sidelined this effort. ALPA has created a Web survey to gather pilot feedback about this flight crew screening system. Please complete the survey and help the Association formulate its strategy for future CrewPASS promotion and advocacy.

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