The accident happened when the plane somersaulted after overrunning the small airstrip at Attar, in the south of the country. All three passengers were flown to neighboring Kenya - from where their flight had departed - where they were taken to hospital in Nairobi.
Most seriously hurt was Karin Van der Valk, from Australia, who suffered head and neck injuries. Her Dutch husband, Anton, escaped with minor cuts and bruises, while Penny Lancaster, also from New Zealand, broke a rib.
The trio were on a July 27 flight to Attar, where they were to join members of a Medair crisis relief team based in the village. Lancaster's husband, Warren, and three other Medair workers - who were among those waiting to meet the flight - helped rescue the injured.
"It was a terrible shock for them to witness," said Medair director Dr Erik Volkmar from the organization's Lausanne, Switzerland headquarters, adding that the three passengers' escape had been "quite miraculous".
"The plane did not burst into flames even though it was still carrying quite a lot of fuel, and while Karin's injuries were the worst they could have been far more serious - she could have easily been paralyzed," said Dr Volkmar. "Also, it just so happened that other flights were available to get them to the hospital that same day."
The three arrivals were due to have helped ease the small Medair team's workload. In Attar, Medair workers are caring for malnourished children, running a clinic, training community health workers, distributing seeds and tools, and preparing teacher-training services for local schools.
Largely cut off from the outside world by fighting in the country's ongoing civil war, the 50,000 people in the area have faced food shortages and lack of medical care for several years. Medair began a 12-month aid program in Attar earlier this year.
In March, a Medair worker in Russia died along with his translator when their vehicle was crushed by an armored personnel carrier as they returned from coordinating an aid shipment for refugees.
Medair was founded in 1988 as a partnership between Youth With A Mission, Mission Aviation Fellowship, and the French medical charity Medicaments pour l'Afrique.