One of the four people killed after a mid-air collision between a plane and a helicopter has been named as Captain Mike Green.
He was a senior instructor with more than 30 years of experience, and a member of the Helicopter Services team based at Wycombe Air Field in Buckinghamshire.
Mr Green was flying the two-seater helicopter involved in the crash.
Captain Phil Croucher, his friend, told Sky News: “I have known him for 20 odd years. We were both in the Army, we worked together.
“He was an ultra nice chap, very professional, would go out of his way to help people get on in their careers.
“He will be fondly remembered by everyone who knew him.”
The mid-air collision happened just after 12pm on Friday.
Investigations at the scene are expected to continue through the weekend and into Monday as detectives work out what happened in mid-air to cause the collision.
Both aircraft came from Wycombe Air Park, also known as Booker Airfield, which offers flight training.
The plane that crashed was a Cessna 152, which has the capacity for one pilot and one passenger.
Waddesdon Manor said in a statement: “Lord Rothschild and his family extend their condolences to the families of all affected, and their thanks to the emergency services for their swift response and professionalism.”
On Saturday, investigators from the Air Accidents Investigation Branch (AAIB) were seen carrying bags of debris in clear plastic bags.
Fire investigators and police remained at the scene, with a cordon in place.
A woman who was walking her dogs at the time of the collision said she heard a helicopter circling overhead “and then heard sirens” and smelled smoke.
Waddesdon Estate gardener, Len Bellis, had been working nearby when he heard a “horrendous noise” before finding the “burning wreckage”.
Mr Bellis said the aircraft was a “wreck” and “non-existent”, apart from the burning fuselage.
A police cordon is in place outside the entrance to the Waddesdon estate.