‘Challenge’ in fighting airport fog

Christchurch Airport and its navigation service face a ‘‘robust challenge’’ in talks with airlines over technology to cut fog disruption to flights.

Fog interrupts services at the airport an average of 11 days a year. This year has been particularly bad, with 19 fog days already. On Monday, at least one flight was diverted and several others delayed or cancelled when fog descended on the airport about 9am.

The airport is considering upgrading its landing system to ‘‘category three’’ (CATIII), which would allow some flights to be guided by radio signal and land in near-zero visibility. It is currently equipped for category one, which allows for landings when fog is at least 200 feet above the ground, although some elements of its landing system are already being replaced with CATIII-compliant equipment.

A full upgrade would require installing high-intensity lights for extra guidance and a radio aid capable of guiding planes to ground level. Aircraft must have specially-trained crew and onboard technology able to communicate with the ground. The airport is looking at installing surface radar to direct traffic on the ground and increase CATIII capability.

The estimated cost of the upgrade is $14 million. That would initially be covered by the airport and national air traffic controller Airways – which would own and operate the assets – and recouped from airlines through landing fees and other charges.

Airways general manager system operator Tim Boyle said Christchurch Airport formally asked for more detail about CATIII about six months ago. The three parties needed to discuss and agree on the viability of an upgrade before going ahead.

‘‘There is certainly a robust challenge from the airlines,’’ Boyle said, ‘‘Like any business, if we want to make an investment we have to justify it and we have to ensure that it’s actually a worthwhile investment.

‘‘I’d say there was a healthy tension. They hold us to account for our investment decisions. They want to see their money spent wisely.’’

Auckland Airport upgraded to CATIII in 2008.

‘‘The decision . . . was really clear in terms of the number of flights that were diverted if we didn’t put it in and it stacked up very well,’’ Boyle said.

‘‘Christchurch is getting to the point now where, my gut feel is, it would also stack up pretty well. Just based on the number of fog days we’ve had and the increase in traffic.’’

He pointed to a recent Christchurch-bound Singapore Airlines flight that was diverted to Ohakea air force base near Palmerston North for several hours while fog cleared.

‘‘It doesn’t take too many of those per year to make the system cost-effective.’’

Only some aircraft could use the upgraded system. Jets, such as Boeing 737s and Airbus A320s or bigger, tended to come equipped with CATIII-capable technology, Boyle said. Smaller, turboprop planes, like those that service regional New Zealand routes, did not.

Air New Zealand did not respond to specific questions, but said the case for installing CATIII technology was ‘‘a broader discussion for the airport, Airways and the airlines that operate services to Christchurch’’.

A spokesman for Qantas Group said the company was happy to work with Christchurch Airport and Airways to consider the upgrade.

‘‘The Qantas Group supports fit-for-purpose investments at airports that demonstrate customer, cost, and value benefits to all airport users.’’

Board of Airline Representatives New Zealand executive director John Beckett said the upgrade at Christchurch was inevitable.

‘‘Essentially airlines see that CATIII will be required at some time at Christchurch and [recent fog disruption] has shown that.’’

"I'd say there was a healthy tension. [The airlines] hold us to account for our investment decisions." Tim Boyle, Airways GM system operator