China is considering the use of military technology that monitors a pilots' in-flight physical and mental state on civilian airliners to improve air safety, according to scientists involved in the research.
The installation of pilot monitoring systems has been discussed by the international aviation industry for years, but the idea is fiercely opposed by pilots on privacy grounds.
After a long delay in recovering Air France flight 447, which crashed into the Atlantic Ocean in 2009 on a flight from Rio de Janeiro to Paris, and the recent disappearance of Malaysia Airlines flight 370 last month, some air safety experts and passengers are calling for increased in-flight monitoring of cockpit crews.
The People's Liberation Army developed a pilot monitoring system that was being used by its air force, the PLA Daily reported in 2005.
Its core components are contained in a lightweight vest which is worn by the pilot.
The 200-gram vest gathered various data, including the pilot's pulse, respiratory rate, muscle movement, body temperature and seating position, constantly relaying the information back to controllers for detailed, real-time assessments of the pilot's physical and mental status.
Professor Zhuang Damin of Beijing University of Aeronautics and Astronautics, who studies the interaction of humans with computers, said authorities were encouraged by the vest's military performance and were interested in potential civilian applications.
Zhuang was lead researcher in a government-funded study to develop a pilot monitoring system for civilian airlines.
"The ultimate goal is to monitor airline pilots as comprehensively as our astronauts," he said.
Zhuang's team developed a cockpit-mounted system to track the precise movements of a pilot's eyes to detect changes in attention level.
Computer and mathematical models were developed based on data findings, with the goal of detecting abnormalities in a pilot's behaviour or voice patterns. Controllers on the ground would receive warnings in the event a behavioural anomaly persisted.
"Our work was at the research stage," Zhuang said. "There was no concrete timetable for implementation."
But Zhuang said the disappearance of flight MH370 en route to Beijing on March 8 might revive the research project.
Professor Li Huijie, a researcher with the Chinese Academy of Sciences' Institute of Psychology, said a cockpit-based pilot monitoring system still faced numerous technological challenges, especially in measuring pilots' mental status.
Reports from such a system were usually based on the assumption that certain behavioural patterns would reflect certain mental states, but the machine could not detect nuances or complex psychological scenarios.
"If a pilot is aware of the installation of such a system on board, he may very likely change his or her behaviour," he said.
An aviation safety expert with the Civil Aviation University of China said that after the crash of Air France flight 447 there were calls to install cameras to monitor flight crews, but pilot opposition had kept cockpits camera-free. "Airline pilots are one of the most respected professions in the world" and felt the introduction of cameras insulted their professionalism, the expert said.
"On long-haul flights pilots will discuss a range of personal and professional topics they don't want to share with controllers," the expert said.