An Australian Transport Safety Bureau (ATSB) spokesman said the pilot and two passengers were flying in a Cessna 150 shortly after 1pm.

''The pilot became incapacitated and the passenger was in the aircraft looking after things for a time,'' he said.

''I don't know how long.''

Police said the passengers raised the alarm with air traffic controllers, who gave them instructions to circle the aircraft over the Forbes Aerodrome and dump fuel in preparation for an emergency landing.

However, the pilot's condition improved and he landed the plane safely at the aerodrome, where emergency services crews were waiting.

An NSW Ambulance spokeswoman said paramedics arrived about 2pm to find the pilot, 61, conscious and suffering from chest pains.

He was flown to Orange Base Hospital for treatment, where last night he was in a stable condition.

The passengers were not injured.

The ATSB would carry out a full investigation, the spokesman said.

''The pilot was able to land the plane safely in the end, and it's just a good outcome at the end of the day,'' he said.

An Air Services Australia spokeswoman was aware of the incident but said the plane was flying in uncontrolled airspace.