The pilot and an 11-year-old boy injured after a light aircraft crashed at Canons Ashby in the south of the county are recovering in hospital.
Police were called to the National Trust property near Daventry at 11.45am on Monday morning.
A woman who lives near the scene, who declined to be named, said she saw a plane fall from the sky, narrowly missing a lake in the grounds of the manor.
She added: “It was a biplane, and suddenly the engine cut out. It just spiralled out of the sky.
“It’s a good job it didn’t come down in the lake.”
Ben Nichols, 19, who lives at nearby Lodge Farm in the village, saw the plane spiral to the ground with sister Zara, 20.
Mr Nichols said: “We were working the sheep at the time.
“Then we saw this two-seater biplane, it was whirling around a bit, looked like it tried to do a loop.
“Then the engine cut out.
“It spiralled down a bit, regained a bit of control and landed with a thud.”
He added: “When I went down it looked like it had had a good landing, given the circumstances.
“The cockpit was a bit smashed up with one of the wings but not as bad as we first thought.”
Zara Nichols said the plane “hadn’t left a mark where it landed so it must have gone straight”.
Mr Nichols said it had landed “on the flat” just yards from a fishing lake and a line of trees, and not far from ridges and furrows in the land.
“He obviously picked the right spot”.
He said it was not unusual to get planes flying over the area, which is not far from several airfields.
An East Midlands Ambulance Service spokesman said: “We received the emergency 999 call at 11.44am reporting that a light aircraft had crashed near Daventry.
“Our emergency operations centre immediately dispatched highly skilled clinicians in a fast response vehicle, two air ambulances and an ambulance was sent by South Central Ambulance Service.
“Two people were reported to be in the aircraft at the time of the incident.
“Hospitals were pre-alerted that the patients would be coming to them for emergency assessment and treatment.
“Both air ambulances provided journeys to hospital.”
The Warwickshire & Northamptonshire Air Ambulance also attended the incident, arriving to find both casualties trapped in the aircraft.
After initial assessment, the air ambulance crew concentrated on treating the youngest casualty whose injuries were more severe.
They worked withe the fire service, land ambulance crew and sister service, Derbyshire, Leicester & Rutland Air Ambulance, to ensure the patients were treated as quickly as possible.
The boy was freed from the aircraft with the assistance of bystanders and his injuries were assessed. He was given advanced pain relief and medication to help prevent further bleeding before being flown to Birmingham Children’s Hospital for further assessment.
The second patient, a 50-year-old male, was flown by Derbyshire, Leicestershire & Rutland Air Ambulance to University Hospital Coventry and Warwickshire to receive further treatment.
Paramedic Jenny Conway said: “With the help of National Trust employees, who were first on scene, reassuring the casualties until we arrived and continuing to assist us and the other emergency services throughout the incident, we were able to free the casualties safely, and transport them to the appropriate trauma centres.
“It is important that once our patients have been treated on scene we can get them to the hospital most suitable for their injuries, which is not necessarily always the closest, giving them a much better chance of survival and recovery. In this instance the two patients involved in the crash yesterday required different specialist treatments and therefore were conveyed to separate hospitals for further assessment with the help of our sister service Derbyshire, Leicestershire & Rutland Air Ambulance.”
A message on the Twitter feed for Canons Ashby House on Monday said: “Our thoughts are with those affected by the light aircraft crash today in the parkland.
“Nothing was damaged in the house or gardens.”
It also tweeted: “Thankfully no visitors have been affected and the property is undamaged. Our thoughts go out to the injured and their families.”