At 08.58 Greenwich Mean Time (GMT) on 4 May, 1997, Swissair flight 4001 lifted off from Shannon's Runway 24, outbound for New York, with a refuelling stop scheduled at Gander.
You might be forgiven for questioning the need to refuel, but this was no ordinary flight carrying hundreds of tourists and businessmen. It was a Douglas DC-4, now 50 years old, commemorating the 50th anniversary of Swissair's transatlantic services, carrying 36 fare-paying passengers on a nostalgic reminder of the "good old days".
The flight had begun in Geneva on 2 May, exactly 50 years from the date in 1947 when Swiss Air Lines DC-4 HB-ILI, under the command of Capt Walter Borner, had departed for New York on a trip which took 21 flying hours and two refuelling stops, but which was forced by bad weather to divert to Washington DC.
Planning for the commerative flight had begun a long time before that. Swissair's director of advertising, Konrad Korsunsky, who along with Markus Ritzi, a recently retired McDonnell Douglas DC-10 captain, headed the programme, explains: "Late in 1995, we began to look at how we should commemorate our 50th anniversary on the Atlantic. These days there is often a sameness about airline advertising and we wanted to do something different, something that would be remembered."
Swissair had bought four new DC-4s from Douglas: HB-ILI, the seventh-to-last DC-4 to be build, flew its transatlantic inaugural in May 1947. It took two years to build the experience and operations network needed to sustain a scheduled service, and the DC-4s stayed on the service until 1951 when DC-6s replaced them.
"Only seven airlines operated the DC-4 as scheduled equipment on the North Atlantic," says Korsunsky. "American Overseas was the first, routing New York-Gander-Shannon-Hurn on 23 October, 1945. The others were Pan American, KLM, Air France, SAS, Sabena and ourselves.
"A commemorative flight with a DC-4 was an idea that sounded promising. But first of all we had to find not just a DC-4, but one that would meet the standards of Swissair." He found that there were still about 40 DC-4s (mostly conversions from the military C-54) in service, but only as freighters, tankers or sprayers. South African Airways (SAA), however, had restored an aircraft which was built in 1947, flown by SAA until 1966 and then served with the country's air force until 1993, and was now using it on flight safaris. "We had found our aircraft," says Korsunsky.
SAir Group (Swissair's holding company) chief executive, Philippe Bruggisser, agreed to the plan, and Korsunsky was left to negotiate a lease with SAA. "Thirty-four years working for Swissair, and this was the first lease I had ever negotiated," he says. "We agreed to wet-lease the aircraft for three months, from 25 April , getting SAA to provide crews, engineers and maintenance. SAA also agreed to paint the aircraft in the 1947 DC-4 colours of Swiss Air Lines."
The biggest worry that Korsunsky had during the project was that KLM might have the same idea. One of the South African DC-4s had been put into service by the Dutch Dakota Association. "If they had flown a transatlantic commemorative service, it would have been before us; our exclusivity would have been lost, and we would have dropped the idea," he says.
The 1997 flight was not as hurried as its predecessor; instead of leaving Geneva at 00.01, a time chosen to ensure that arrival and departure at Shannon and Gander were in daylight, 14.00 local time/12.00GMT was selected (all later times given are GMT). Take off was at 12.36, and, a leisurely 4 h 1min later, the DC-4 landed at Shannon. Weather had been good, and a tailwind had helped.
Two days later, the flight continued across the Atlantic to Gander. (The DC-4 was fitted with 50 Rumbold first-class seats, with the footrests removed, but the Shannon-Gander sector required maximum fuel, so passenger numbers were restricted to 36 and each was permitted only 15kg luggage on board - additional luggage followed on other Swissair flights.) The Atlantic was crossed at an initial altitude of 2,000ft (600m), climbing gradually to 8,000ft as fuel was burned off. That was high enough for the unpressurised DC-4. The three cockpit crew, all from SAA, had the benefit of a global-positioning system, which simplified navigation and allowed the crew to follow an accurate great-circle track to bring the aircraft to Gander in 9h 40min. Average speed was 190kt(350km/h): a tailwind had cut the flying time by almost 90min.
After a two-night stopover, the flight departed for New York. The weather stayed good most of the way as the DC-4 flew along the coast of Canada and the USA, staying at lower levels to avoid icing - spares for DC-4s are no longer plentiful, and de-icing boots are hard to come by. As Flight 4001 neared New York, it looked for a while that it might have to divert: not to Washington as in 1947, but to Boston. Eventually, however, the cloud and mist dissipated, and just under 7h after take-off, the DC-4 landed smoothly at New York's Kennedy Airport (known as Idlewild in 1947).
While the westbound passengers parted with the DC-4 here, it spent three days carrying sightseers from Kennedy to Newark, New Jersey, then others to New York La Guardia, and still more back to Kennedy. In each case the short distances allowed its full complement of 50 to be carried.
On Saturday 10 May, a new load of passengers began the return flight. Following the same leisurely route, they arrived back in Zurich (not Geneva) shortly before 13.00 on 14 May.
While the aircraft remained in Swissair (or Swiss Air Lines to use the 1947 name) service, other passengers were flown internally in Switzerland and on services to Athens, Cairo, Luxembourg, Nice, Olbia, Pantelleria, Prague, Rennes and Salzburg; at Gander and Shannon local flights took place. A second transatlantic special was operated over the same route from 5-16 June. Some 2,028 passengers were carried on the aircraft. The project earned valuable publicity for Swissair and, says Korsunsky, "we actually covered our costs."
For the lease, Swissair and SAA did as much as they could to recreate 1947 authenticity. The original HB-ILI registration could no longer be used, so the South African authorities allowed the DC-4 to be registered ZU-ILI. For one flight in South Africa, and for two in Switzerland, all for publicity photographs, the HB-ILI mark was permitted.