Safety fears have been raised following the Qantas mid-air emergency last week. MARK LOURDES speaks to aeronautical experts.

YES, that mobile phone call, open laptop or handheld electronic game can kill the tedium of a long flight. But think again before you use it.

The electromagnetic interference (EMI) generated by most electronic equipment can affect the sophisticated electronic systems of airplanes, including the aircraft's navigational equipment.

EMI emanates from the transmitters in many communication devices that have WiFi and Bluetooth capabilities, among others.

Universiti Sains Malaysia School of Aerospace Engineering's professor Vladimir Zhuravlev said the use of such equipment onboard a plane could cause many problems as more and more onboard subsystems were equipped with electronic control elements.
"The use of these electronic devices can lead to errors in the autopilot systems, navigation systems and other onboard subsystems managed by electronic control elements," he told the New Straits Times.

Zhuravlev said the EMI in electronic devices was similar in principle to military electronic countermeasures that electromagnetically jam enemy electronic systems.

He said the main reason such devices were not banned from flights right from the beginning was because the authorities did not expect the problems they would create.

"In many cases, management decisions were made by persons who were not specialists in the appropriate fields. They thought about economics and advertising, but not about technical problems and safety."

However, Zhuravlev said airline safety was always improving. "Aviation is still a safer mode of transport compared to all others."

An example of the continuing improvement is the installation of miniature onboard base stations, called picocells, to facilitate wireless communications between the aircraft and the outside world.

The picocell regulates the transmission levels of electronic devices, ensuring they do not interfere with either the airplane's systems or mobile communications systems on the ground.

While most countries restrict the use of mobile phones during flights, the European Union in April opened the way for flyers on planes with base stations -- which are mainly newer aircraft -- to use mobile phones in the continent's airspace.

Zhuravlev cautioned that the presence of such a base station would not necessarily take care of the problems EMI pose.

"I think the EU's decision was a mistake. The presence of a base station on the aircraft does not negate all the problems of electromagnetic interference. I think the EU will change its mind."

Zhuravlev concurred with the view of an Australian expert that the recent case of a Qantas aircraft plunging out of control while 37,000 feet in the air could have been caused by active electronic devices onboard.

"I think the operation of laptops, mobile phones or electronic games could cause an accident."

He added, however, that nothing could be said for certain until the aircraft accident investigation had been completed.

Other possible reasons for the incident, he said, included vertical windshear (wind gust) and soft errors in the autopilot or navigation systems.

The pilots of Qantas flight QF72, en route from Singapore to Perth last Tuesday, called in a mayday and made an emergency landing after losing control of the aircraft.

Initial investigations by the Australian Transport Safety Bureau revealed that the plane climbed about 200 feet from its cruising level of 37,000 feet, then pitched nose-down and descended about 650 feet in about 20 seconds before returning to cruising level.

It then again nose-dived 400 feet in about 16 seconds before returning once again to the cruising level.

The terrifying incident left 12 people seriously injured and 30 more in need of medical attention.