A pilot flew the Essex Air Ambulance round a field at 300 feet on a safety check before landing -- but did not see power lines until it was too late.
The helicopter hit three power lines, and a broken one set the stubble field alight as the 53-year-old pilot managed a successful landing in the field off Beggar Hill, Ingatesone.
An Air Accidents Investigation Branch, AAIB, report reveals that the pilot was suddenly aware of power lines immediately ahead.
"He tried to stop, but the power lines, consisting of three wires, struck the helicopter just below the cockpit bubble," says the report.
"One wire seemed to break on contact, but the pilot had to manoeuvre the helicopter to break free; in so doing, a second wire broke and the automatic direction finder aerial detached."
Neither the pilot nor two paramedics in the helicopter were hurt.
The pilot told AAIB investigators that the sun was not a factor and that the power lines were well hidden.
The report adds: "He also considered that 'wire cutters' on the helicopter might have resulted in a clean cut to the wires.
"The provision of wire cutters is not a requirement and would obviously result in a weight penalty with adverse effects on performance and payload.
"The danger of power lines is a well known hazard for low-level helicopter operations, and the best counter to the danger remains an effective air and or ground reconnaissance."
The report reveals there was a marshal on the ground, but there was no radio contact.
Power to 500 homes was cut after the crash.
The air ambulance had been alerted after an 11-year-old boy fell from a tree on the afternoon of September 5.
Converted for the new archive on 19 November 2001. Some images and formatting may have been lost in the conversion.
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