Diversionary tactics for Atlantic aviation

The good news for airline passengers: a new runway has at last been built on British soil, south of London.

The bad news: it’s really quite a long way south – nearly 5,000 miles – on the only vaguely flat swathe of terrain on the remote UK possession of St Helena.

The worse news: no-one knows when commercial flights from Johannesburg to the £250m airport will begin. Safety concerns mean a frustrating wait for the Saints (as the islanders are known), UK taxpayers and prospective tourists.

Last month a Boeing 737 touched down at St Helena airport. The first large passenger plane to do so, it was operated by a South African airline, Comair, in the colours of British Airways.

Initially the landing was claimed to be a success, despite some “go-arounds” before the aircraft touched down. Martin Louw, operations director for Comair, said: “We did a few practice approaches just to make sure we understood the approach.”

But within a few days the royal opening – planned for 21 May - had been cancelled. The proving flight had revealed concern about windshear, the phenomenon in which the speed and direction of the air changes quickly.

Brian Heywood, a former British Airways pilot, says he warned the UK Government years ago about the risks. He told the island’s newspaper: “The airport authority can discuss it for ever more, but nothing will change the local topography. If an airport is built on the edge of a near-vertical 1,000-foot cliff, the prevailing wind is bound to cause problems.”

Other high-rise, exposed islands also experience weather problems such as windshear. Hundreds of British travellers found their stays on Madeira this week unexpectedly extended, at the airlines’ expense, when easyJet and Thomson Airways postponed flights for 24 hours until the weather improved. The airport is carved out of the side of a volcano, with a runway extension on stilts.

There is a big difference, though, between Madeira and St Helena. The Portuguese island has plenty of diversion options nearby.

Flight crews must carry enough fuel to divert to an alternate airport, and still have half-an-hour's fuel left over. Over Europe, the Americas and Asia, finding an alternate is straightforward. Even for Madeira, the diversion options are nothing to get stressed about. Porto Santo, the sister isle, is only 40 miles away. If that airport is also closed, then Tenerife is 300 miles south. And if this whole patch of the Atlantic is kicking up a storm, then Marrakech is safely inland about 500 miles – a little over an hour’s flight – to the east.

Life gets trickier on the flight deck when you are a long way from land. For travellers to and from St Helena, adrift in the South Atlantic west of Namibia, isolation is not so splendid. The nearest alternate airports are Ascension Island, two hours away, or the Angolan city of Lubango, three hours distant. Were there any uncertainty about the weather in Ascension, the captain would aim for Africa, where the Angolan capital, Luanda, is another choice. But after a four-hour flight from Johannesburg, the reserves start to get depleted.

What can be done to get a safe, swift resolution to the problem, so that the huge investment in the airport can start to pay dividends? A question for Richard Brown, principal of Atlantic Star Airlines. He aims to fly a rival service from Luton via Banjul in the Gambia to St Helena – a faster, cheaper alternative for UK travellers.

“Once sufficient meteorological data has been gathered it will be relatively straightforward to predict the occurrence of windshear,” he says. Operators can then plan accordingly.

“For travellers interested in visiting this remote and wonderful island, that might mean an occasional flight delay or reschedule to a different day with a better weather factor. The team at Atlantic Star Airlines is confident that safe flight operations will be achieved and that St Helena will be worth the wait.”