Looking beyond the headline-grabbing issues of in-flight avian-flu transmission or biochemical attack, a group of researchers with funding from the Federal Aviation Administration (FAA) are pursuing several more prosaic concerns to ensure cabin air-safety and air-quality.
Today, those concerns focus on developing an onboard sensing system of airborne contaminants that’s both practically and economically feasible, says Auburn University‘s William Gale, who also is the executive director for the Air Transportation Center of Excellence for Airliner Cabin Environment Research (ACER). Many studies already have looked into various types of sensors for detecting air quality in public places, but not in aviation.
ACER, consisting of an eight institution “core team” that includes the University of California, Berkeley, Harvard, and Purdue, is headquartered at Auburn. Since March 2005, the FAA’s Office of Aerospace Medicine has funded its research.
ACER’s investigations into sensing systems, contaminant transport, and a nearly market-ready aircraft decontamination process, could be applied to diseases such as avian flu, Gale says.
The FAA remains noncommittal. It is not FAA’s intent to develop or recommend any specific responses to avian flu, says Chris Seher, FAA’s ACER program manager. “We don’t want anyone to think [these things] are what FAA thinks should be done if avian flu breaks out,” Seher emphasizes.
Nonetheless, ACER’s work continues apace. One approach for onboard sensing that ACER scientists are studying involves the use of small sensor strips that resemble pregnancy test strips. They’re cheap and could be readily deployed by cabin attendants, but the real issue involves their unproven reliability.
Small test strips are already in use by some first responders and the U.S. military, but not by airline flight crews. However, they could easily resolve certain in-flight situations – say, the sudden appearance of an unknown white powder. Most of the time the substance turns out to be harmless, but unless there’s a quick way of determining whether it is, passengers are apt to panic.
Other possibilities are sensors built into the air-return system or pairing on-board sensors with rapid ground-based verification. That said, Gale insists that existing sensor technology is not yet reliable enough for making emergency-landing decisions.
One problem with getting more reliable results is that onboard testing can’t rival testing in clinical laboratory conditions, where there are few constraints related to space, weight, size, and power.
Another future option might be an air-quality data transmission system between an onboard sensor and a ground-based facility or expert. This brings to mind the portable onboard medical devices that enable ground-bound physicians to diagnose passenger conditions (Air Safety Week, June 5). In both applications, the communication needs are the same, Gale says.
But none of this investigative work into onboard sensors is as far along as ACER’s decontamination project. For the past six months, at Orlando Int’l Airport (MCO), Aeroclave Inc. in Orlando and Mentor, Ohio-based Steris have been demonstrating systems that clean the air of craft on the ground. Part of the trick has been developing systems that don’t damage avionics or necessitate dismantling sections of the craft.
For viruses, the cabin and cockpit can simply be filled with air heated to 60 degrees Celsius. But for harder-to-kill contaminants, a hydrogen peroxide vapor is as effective as it is practical, Gale explains. After use, the vapor breaks down into water and oxygen, so there’s no noxious chemical waste. These systems have been used only on Boeing DC-9s, and there are plans to start testing on 747s.
There also are several more ACER projects in early stages of development. One involves the use of onboard ozone sensors, and determining whether FAA’s current levels of safe ozone levels are appropriate. Another project is looking into the spraying of pesticides inside the cabin, which is commonly done outside the United States.
Still another is dubbed “contaminant transport” (inside the cabin), which has been collecting data for some time and is being prepared for testing in an aircraft cabin mock-up. With symptomatic passengers who cough, it’s very important to determine where the contaminated droplets go. What ACER researchers have learned is that most of a cougher’s spray doesn’t go very far, but the lucky passengers one row ahead get “bathed,” Gale says.
Finally, there’s one project that leaves the issue of contaminants aside to investigate the passenger health effects of cabin air pressure. For ethical reasons, such research until now has been conducted by putting healthy subjects into a special chamber. But the question has arisen over whether there’s any more to learn from such a study design, or if it’s time to focus on frailer people who can really suffer from changes in air pressure. ACER researchers have just begun considering some new experimental designs, which may involve researchers sitting next to trial subjects aboard flights or self-reporting by the subjects.
>>Contacts: William Gale, ACER, Auburn, 334-844-3406, [email protected]; Qingyan Chen, Purdue, 765-496-7562, [email protected]; John Spengler, Harvard, 617-384-8810, [email protected]<<