On Dec. 18, two women were killed when their light aircraft slammed into a suburban house in Sydney after a mid-air collision with a plane flown by an 89-year-old instructor and his 25-year-old student, which later landed safely.

A young woman and her newborn baby who lived in the house were only saved because they had gone out to visit Santa Claus.

An instructor and her female student in a Cessna 152 died in the crash. The other plane landed at Bankstown Airport.

The second plane's male instructor and student were unhurt and their single-engined Liberty suffered only minor damage.

No one was in the house when the Cessna hit. The mother and her baby had left shortly before the crash, the woman's father said.

"She took the baby for a photo with Santa Claus sometime this morning," said Gino Velerio.

His daughter Bianca and one-week-old grandson normally spent most of their time in the kitchen at the back of the house near where the plane crashed, he said.

Witnesses described watching the aircraft smash into the rear of the house in the suburb of Casula in Sydney's southwest.