Volume 8, Number 6     November/December 2000

Monitor Could Improve Air Safety

The innovator of the Personal Cabin Pressure Altitude Monitor and Warning System hopes the system will improve air safety.

NASA Kennedy Space Center's (KSC) Jan Zysko, the system's innovator, said, "If this technology can help to avoid even one incident or accident, it will have been worth all the effort put forth over this past year."

A device about the size of a pager may save pilots' and astronauts' lives by alerting them to potentially dangerous or deteriorating cabin pressure altitude conditions. Photo provided by NASA Kennedy Space Center.

The device is a hand-held instrument that can warn the user of potentially dangerous or deteriorating cabin pressure altitude conditions. Zysko, chief of the Spaceport Engineering and Technology DirectorateÕs Data and Electronic Systems Branch, said the monitor, which is about the size of a pager, operates independently of other aircraft systems. It monitors the pressure/time conditions when supplemental oxygen is to be used per applicable Federal Aviation Regulations (FAR). The monitor is user-programmable and incorporates a highly accurate pressure transducer. It warns the user of impending danger of hypoxia through simultaneous audio, vibratory and visual alarms. In addition, a lighted digital screen displays a text message of the warning and the condition causing the alarm.

The monitor was conceived to give Space Shuttle and Space Station crew members added independent protection from "an incipient depressurization event," Zysko explained. Two major incidents galvanized in Zysko's mind the need for such a device: the Mir/Progress collision in June 1997 and the Payne Stewart aircraft accident in October 1999.

Hypoxia, a state of oxygen deficiency in the blood, tissues and cells sufficient to impair functions of the brain and other organs, is a major concern to pilots. The symptoms of hypoxia often go unrecognized, since the brain is the first organ to be affected. Once hypoxia occurs it is difficult, and often impossible, for the person to acknowledge the situation or take corrective action. In the early stages, there is considerable loss of judgment and cognitive ability. The person may become euphoric or even belligerent, and in the later stages, suffer impaired visual, physical and motor skill functions before succumbing to unconsciousness and eventual death. The length of time required for a person to lose useful function after being exposed to reduced cabin pressure is based on the physiological condition of the person and the pressure altitude. At 35,000 feet, a common altitude of commercial air carriers, the time of useful consciousness (TUC) is 30 to 60 seconds. If the cabin pressure loss is sudden, the TUC is reduced to only 15 to 30 seconds.

Zysko and the KSC team involved developed this technology from concept to prototype to commercialization in less than 12 months, at a total cost of less than $100,000. He emphasized the cooperation, collaboration and interest from multiple government agencies, including the National Transportation Safety Board (NTSB), the Federal Aviation Administration (FAA) and the U.S. Air Force. Dynacs, Inc., the KSC engineering development contractor, played an important role in the circuit design and fabrication of the prototype.

Licensing Manager Melanie Chan explained there are several potential NASA and aviation/aerospace applications. Pilots flying both pressurized and non-pressurized aircraft could benefit from the warning system. Human-tended space operations also could use the innovation. Low-Earth orbit (LEO) vehiclesÑthe Space Shuttle, International Space Station and MirÑare markets, as are long-duration/interplanetary vehicles and future planetary habitats. Ground systems are also applications, including the Mars simulation chamber and pressure/vacuum test chambers.

Zysko added that applications beyond aviation and aerospace include scuba diving, skydiving, mountain climbing, meteorology, underwater habitats, hyperbaric chambers, altitude chambers and positive/negative pressure vessels. ÒFor pressurized aircraft, the invention provides an independent warning of cabin pressure altitude where a cabin leak or other reason for pressurization loss might go undetected,Ó he added. "For non-pressurized aircraft, the monitor tracks time and altitude profiles and warns when supplemental oxygen is needed per the applicable FAR."

During the next phase of development, Zysko would like to integrate carbon monoxide (CO) and carbon dioxide (CO2) sensors into the unit for more complete aviation and aerospace environmental monitoring. The presence of CO in an aircraft environment due to engine exhaust gases entering the cockpit is a significant aviation hazard. The CO2 sensor addition would be particularly helpful for independent monitoring of the CO2 scrubber effectiveness on long-duration space vehicles and space habitats.

A private pilot, Zysko illustrated the need for his invention with a significant number of hypoxia and cabin pressure-related incidents contained in the NTSB and FAA accident and incident databases. He said the FAA and NTSB agree that there are probably many more hypoxia-related incidents and accidents, but there is insufficient evidence to list hypoxia as a probable or contributing cause.

For more information, contact Thomas Gould at NASA Kennedy Space Center. Call: 321/867-6238, E-mail: Thomas.Gould-1@ksc.nasa.gov. Please mention you read about it in Innovation.

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