Airbus A380 training captain Douglas Haywood and recently retired captain Ross Kelly were among the 19 people aboard the Convair 340 aircraft when it crashed into a factory near Pretoria's Wonderboom Airport on Wednesday afternoon (Thursday AEST).

A South African flight engineer on board the 64-year-old plane and a factory worker were killed.

The two Australians were among about 20 people injured.

Several people were trapped in the smoking wreckage of the 44-seat plane, according to private emergency service ER24.

The ageing plane had been on a test flight before its imminent multi-stop trip to its final home at Dutch museum Aviodrome.

Aviodrome said the aircraft was restored and tested ahead of the trip via Zambia, Uganda, Sudan, Egypt, Croatia and Austria to Lelystad.

Both Australians, who have more than 30 years' flying experience, were involved in a similar trip when they flew another Convair 340 from Pretoria through Asia and to NSW's Historical Aircraft Restoration Society.

The pair have been members of HARS for decades, while Mr Haywood was a former air force pilot before he joined Qantas in 1984.

Mr Haywood, now an A380 check and training captain, has long been involved in restoring and flying vintage planes.

Mr Kelly and his wife Lyndal arrived in southern Africa in late June and toured extensively before arriving in Pretoria.

Ms Kelly was also reportedly aboard the stricken flight and believed to be in a stable condition, according to News Corp Australia.

Qantas said it was providing whatever support it could to the pilots, who are in hospital being treated for serious injuries.

"This news has shocked the Qantas pilot community and everyone's thoughts are with the families," a spokesperson said in a statement on Thursday.

The South African Civil Aviation Authority said two Australians, three Dutch people and 14 South Africans made up the flight's three crew and 16 passengers.

Australian Associated Press