A caller to the station said it was approaching over The Barn and taking a wide arc round Levelwood as it neared the end of an 1,100-mile flight from Angola.
And then, a few minutes later, host Catherine Turner declared: “I can definitely assure you that the plane has landed and is taxi-ing in to the airport.
“The first flight to land at St Helena ever landed at just after a quarter to two this afternoon. We can now genuinely say we’ve got an airport.
“I’m breaking up. It’s so exciting.
“When we looked out in the street [in Jamestown] the only thing we could see moving was a cat. I think everybody must be up there.”
Catherine played Dido’s Thank You in tribute to “the hundreds of people involved in building, testing, everything.”
She followed that with locally-written song, Beat of the Airport Drum.
Neil George phoned in to the station to say he was speechless to see a plane land on St Helena. He was among about 200 people watching from the Millennium Forest.
The aircraft circled the airfield twice before touching down on the third approach – based on calls to the studio in Jamestown.
“There’s nobody in the shops, nobody in the street,” said SAMS Radio 1. “It’s been a success.”
Giselle Richards of G-Unique was among those who closed their businesses and joined the long tail of people heading up the hill. She posted a picture of herself on Facebook, wearing aeroplane earrings specially for the occasion.
Children had been given blanket permission to miss school to view the landing. Schools would have closed and transported children to vantage points across the east of the island had the flight been expected to arrive in the morning.
Chief of Police Trevor Botting said on Twitter that it was great to see the excitement in his team as the aircraft approached. It was a privilege to be on the island for it, he said.
Five people were aboard the Beechcraft plane, flying out from Angola in order to carry out a series of flights to calibrate landing, navigation and communications equipment.
The aircraft crew comprised Captain Grant Brighton, co-pilot and first officer Dillan Van Niekerk, chief aircraft engineer Jeffrey McKenzie – all of TAB Charters, SA – together with chief pilot Stuart Rawlinson and chief flight inspector Nick Whitehouse, both of Surrey-based Flight Calibration Services.
They had to navigate by GPS alone.
The airport – the UK’s biggest single overseas aid project, costing more than £250million – is due to be completed in late February 2016.
On Facebook, Nick Stevens posted images of a long convoy of vehicles making their way back home along the airport construction routes, which are normally closed to the public.
One person reported on Facebook that the chance to drive on the wide, unmade road to Foxy’s Garage was the main attraction of the day.