A pilot and his passenger were killed when their light aircraft burst into flames as it crashed into a field.
The two men were travelling in a Yak 52 plane when they got into difficulties at around 2.55pm after flying out of North Weald airfield in Essex.
Witnesses described how the training aircraft had been attempting a somersault before going down in a rural area between Ongar and Writtle, near Chelmsford.
Sam Gildersleeve, from Ongar, said he was having lunch with friends when he saw the plane flying low close to the A414 near Cooksmill Green.
Mr Gildersleeve told the BBC: "At this point we all looked at the sky and the plane attempted to do a somersault unsuccessfully, we heard a popping sound and noticed the plane did not re-emerge.
"We then noticed smoke coming from the site in the field where the plane had crashed. Shortly after the emergency services appeared."
The aircraft was "completely alight" when firefighters arrived at the scene near Cooksmill Green, Essex Fire and Rescue Service said.
A spokesman said: "On arrival the incident commander reported that the plane was completely alight.
"Crews used foam and had extinguished the fire by 3.55pm."
A police spokeswoman said: "Emergency services rushed to the scene and fire crews extinguished the fire caused when the plane crashed. Two men, a pilot and his passenger - both from Essex - were on board. The plane had flown out from North Weald airfield."
Two people were killed when a Yak 52 aircraft from North Weald crashed in April 2011.
Instructor Simon Hulme, 33, and his 43-year-old student, Spencer Bennett, were killed when their plane crashed near Langford, east of Chelmsford.
An inquest in Chelmsford in 2012 heard they were on the last day of a three-day formation flying school when the aircraft span and plummeted from 1,800ft into a lake.
The jury returned verdicts of accidental death after hearing nearly two hours of evidence.
In January 2003, Falklands veteran Anthony Hunt, 48, died along with his brother Ian, 45, when their aircraft crashed in a field on the Easton Neston estate, near Towcester, Northamptonshire, while practising aerobatic manoeuvres.
His family were awarded £270,000 damages by the High Court in 2006 after an investigation found that during maintenance a short screwdriver had become wedged into the wires that operated the rear elevators of the plane.
The Yakovlev Yak 52 is a two-seater propeller aircraft first built in the Soviet Union in the 1970s.
The former Soviet Air Force training aircraft is a popular plane for aerobatic flying around the world.
It has a top speed of 223mph and a service life of 30 years, according to www.yak.ru. It is not known how old the aircraft which crashed today was.
Police said that immediate family of the deceased had been informed.