China's airways go on the bleep

Delays due to bad weather are unavoidable, and even the perennial "technical problems" are forgivable, considering the age of some of China's aircraft. But when Shenzhen airport had to be closed for two hours the culprit was rather more down to earth - the perilous pager.

No self-respecting Shenzhenite ventures out of his or her home in the morning without a smart black pager strapped to his belt or in her handbag. But this plague of pagers is proving something of a problem for airport operations and a major hazard for pilots flying near this booming special economic zone bordering Hong Kong.

When Liu Jianhua, deputy director of Shenzhen airport's air traffic control station, came into work at 8.30am on 13 August, noise disturbance was already disrupting ground-to-air communications. By noon interference from pager transmissions in the area was so bad that pilots could not hear air traffic control instructions clearly.

The airport was forced to shut, incoming flights had to be diverted and 11 aircraft could not take off on schedule. The airport reopened two hours later, but the pager pestilence persisted. According to the Shenzhen Special Economic Zone Daily, one China Northern aircraft took off at 3.30pm and as it climbed into the sky air traffic control told it to "turn left". The pilots misheard the instruction, due to continuing interference by pagers, and instead turned right. Fortunately there was nothing in their flight path.

There were around 40 million pagers in China by the end of last year. Many people still do not have telephones at home and the pager is a cheap, convenient messaging system for business and leisure. In the boomtown of Shenzhen most pagers also provide an automatic update on prices on the volatile local stock exchange.

China's air traffic control towers have two operating frequencies but over the last two months both have been severely disrupted at Shenzhen. The problem is the forest of pager transmitters: more than 2,000, run by 67 companies, in the area. Many get into the lucrative business without a proper licence and use radio frequencies illegally.

Du Jian, director of Shenzhen air traffic control, says radio signal disturbance is a problem for many airports around China. Difficulties arise inside as well as outside the cabin. Domestic flights start with a warning to passengers not to use pagers or that other talisman of success in China, the mobile phone, but frazzled stewardesses can often be seen frantically telling passengers to stop talking as the aircraft heads for the runway. The moment a plane lands the phones are switched on again to a chorus of ringing.

A decade of economic supergrowth in China has promoted a boom in modern telecommunications, leading to a prediction that the number of mobile phones in China will triple to 30 million by 2000. Pagers, being much cheaper, have spread far more widely. In Shenzhen the official Radio Control Committee is cracking down: of the 954 pager transmitters it has inspected some 134 have been deemed of "inferior quality", 86 could not meet technological demands and 48 were illegal.