Two people in a single-engine light plane survived after it crashed into a paddock near Camden Airport in Sydney's south-west.
A police helicopter on a training exercise was nearby and landed soon after the crash, which occurred just after 11.20am on Thursday.
The helicopter crew rescued the 24-year-old male pilot and his 23-year-old female passenger, police said.
No one else was in the aircraft, which police believed was a Warrior Piper four-seater.
NSW Ambulance paramedics treated the man for facial and head injuries and the woman for an injured ankle.
The pair were taken to Liverpool Hospital where they are understood to be in a serious but stable condition, police said.
Police and Fire & Rescue NSW firefighters were at the crash scene.
Initial inquiries show the plane had only just taken off from Camden Airport when it developed engine trouble, police said.
It went down not far from Macquarie Grove Road at Cobbitty, about 1½ kilometres north-east of the airport.
The cause of the crash is not yet known.