Five-day fog chaos hit 500 flights

Five consecutive days of sea fog that blanketed Wellington Airport caused one of the worst disruptions to New Zealand airline networks ever.

The fog - generated by a large, slow-moving mass of warm, humid, tropical air drifting over a cool sea - was a rare phenomenon, said MetService forecaster Mark Pascoe.

It was more likely to happen in March, and generally did not hang around as long.

Mike Tod, a spokesman for Air New Zealand - the biggest user of Wellington Airport - said the fog had caused the largest disruption to the airline's network in years.

It affected about 500 flights and at least 10,000 passengers. Of those, Mr Tod estimated 1500 passengers had been bused 140km to Wellington from Palmerston North.

Airport duty manager Stephen Rybinski believed it was the longest fog disruption for the airport. About two years ago, fog closed the airport for two days.

The shutdown started about 6.30pm on Tuesday. The airport was closed for much of Wednesday and Thursday, but able to open for three to four hours on Friday, and again Saturday afternoon.

Large numbers of people flying in for the international rugby sevens tournament managed to get in by bus from Palmerston North.

Some international flights managed to land and take off, generally coming in late in the day and leaving again the following morning.

Backlogs were cleared on Friday and Saturday, with bigger jets brought in to take more passengers than the Boeing 737s.

No information was available yesterday from Qantas about how many of their flights and passengers were affected.

Origin Pacific network general manager Noel Gillespie also had not done a final tally, but said the main thing was that it had managed to get all its passengers where they wanted to go, albeit with delays.

Vincent Aviation managing director Peter Vincent said that, although other airlines would have lost a lot of revenue, his company had been able to come out about even - flights cancelled were offset by extra charter work.

Having Paraparaumu as an alternative airport had been useful for passengers who knew that, even if they could not fly into Wellington, they could at least land an hour's drive away.

Mr Vincent said there was nothing practical that could be done to reduce the impact of fog on Wellington Airport.

Though auto-landing systems were widely used throughout Europe to allow airlines to keep flying in these sorts of conditions, auto-landings were not a realistic option for Wellington.

They were hugely expensive, requiring a big investment in ground equipment, extra systems on aircraft and pilot training.

And, if Wellington's hilly terrain did not rule it out, the airport's runway was too short - airports using auto-landing systems had to have much longer runways.

The cost of installing the equipment in all aircraft and training pilots were unlikely to be an economic proposition.

Rough weather caused most disruptions to Wellington flights and an auto-landing system would do nothing to help that, he said.

Civil Aviation Authority spokesman Bill Sommer said setting up a system to allow aircraft to land in dense fog was not economic in New Zealand, where conditions such as those experienced in the past week were rare.

- NZPA