Hong Kong  - It has been called the Crash of the Century. In heavy fog on a March afternoon in Tenerife, Spain, a packed KLM Boeing 747 roared toward its take-off, oblivious to a Pan Am jumbo jet taxiing in its path at the end of the runway.

A split second before impact, the fog cleared enough for both pilots to see the horror awaiting them. The KLM captain desperately tried to lift his plane off the ground, dragging the tail along the runway before shearing the fuselage of the Pan Am jet apart and ripping an engine clean off the underside of one of his own wings.

In the inferno that followed, 583 crew members and passengers from both planes perished, making the 1977 incident the worst single accident in aviation history. Three decades on, the crash remains the deadliest disaster in airline history - a tragedy on a scale that with today's advanced technology and sophisticated airport systems could surely never happen again.

Or could it? It was a question raised again by a comparatively minor incident in September at Hong Kong International Airport when a Korea-bound Boeing 737 with 122 passengers on board attempted to take off down a taxiway rather than a runway.

In this case, there was no packed jumbo jet lying in wait, and the frantic radio calls of an air traffic controller made the Hong Kong Airlines captain realize his blunder in time to abort take-off.

But 31 years after the Tenerife disaster, the drama in Hong Kong provided a stark reminder of how easy it still is for a disoriented pilot to make a potentially fatal wrong turn.

The captain and co-pilot were sacked as a result of the Hong Kong incident, and a Civil Aviation Department investigation recommended making markings and lighting clearer to avoid a repeat of the incident.

What should set alarm bells ringing, however, was the fact it was the third such incident at the airport in five years. Airport markings and lighting were upgraded after the previous attempted take-off from a taxiway by another airline in June 2007.

Many pilots and aviation experts worldwide agree that while sophisticated new cockpit systems have led to huge advances in the avoidance of mid-air collisions and crashes into the ground in poor visibility, not enough has been done to prevent a repeat of the tragedy of Tenerife.

In the United States alone, a major report found, runway incursions - incidents where planes mistakenly stray onto active runways - take place at a rate of almost one a day. The risk of a single accident killing hundreds of people at an airport is "real and growing larger," warned the report by the Airline Pilots Association International.

The next major airline disaster, many experts said they believe, will not be at altitude or on a mountainside but within the bewildering sprawl of taxiways and runways that spider out across today's constantly expanding international airports.

A senior Hong Kong-based captain said that so far, there had been a general failure within the airline industry to develop sufficient safeguards against collisions between planes within airports.

Some airports, particularly those in major US cities, were a "dog's dinner" and far harder to navigate than Hong Kong, said the captain, who requested anonymity.

"If anybody can try to take off on a taxiway at Hong Kong International Airport, which is one of the best airports in the world, you can see we have a much bigger problem in other airports which are more confusing for pilots," the captain argued.

"Really, the technology we have today isn't too different from what we had at the time of the Tenerife disaster," he said. "Nothing major has been done to prevent an accident of that kind happening again."

The study on runway incursions prepared by the Airline Pilots Association International last year said there had been an average of 325 incidents a year in which planes had strayed onto active runways in the United States alone over the past five years.

Since the Tenerife disaster, there have been five fatal accidents involving runway incursions in the United States, including one in Los Angeles in 1991 that killed 34 people. As well as the fatal accidents, there had been a number of potentially catastrophic near-misses.

"We didn't use the [Tenerife] accident as a wake-up call to develop the technology to prevent it happening again in the same way as we did with controlled flight into terrain, for instance," the Hong Kong captain said. "We should do more."

The association's report also argued for improved technology. Ground radar, not in use at the time of the Tenerife crash, and improved training procedures has helped contain the risk to some degree - but the growth of airports and air traffic has increased the likelihood of a major accident by a far greater degree, it said.

The report called for the introduction of on-board moving map displays, a technological measure that the association estimated would help cut runway incursions by 95 per cent, along with better airport markings and runway status lights and take-off hold lights to improve airport safety.

"The risk of a runway incursion event that could kill hundreds of people in a single accident is real and growing larger," the report concluded. "The current level of risk is unacceptable. Strong and immediate mitigations need to be implemented."

But at a time of global economic crisis with airports emptying and some airlines struggling to survive, how likely is it that anyone will be prepared to make a major investment in on-board plane technology to prevent a repeat of the Tenerife tragedy? (dpa)