Jamie, who also died in the crash, was a keen skateboarder
A pilot who died when he crashed in a field killing his teenage passenger had taken an illegal drug just hours before the accident, it has emerged.
The Air Accident Investigations Branch (AAIB) said Robert Gunter, 33, was found to have had ecstasy in his blood.
The report into last July's crash said the drug would have impaired his judgement and ability.
The father of 13-year-old Jamie Clapp, who also died, expressed his anger at the pilot, who was a family friend.
Jamie was being taken on a birthday flight in the Cessna 150 when it stalled just after take-off from an airstrip in Clutton, Somerset.
Witnesses said the plane had reached a height of about 200ft (60m) after crossing the end of the runway when the engine appeared to stop.
The aircraft rolled to the left and came down striking the ground and bursting into flames.
Flying privileges revoked
The AAIB said Mr Gunter had gained his private pilot's licence in Florida in 2002.
He had done a small amount of flying in the UK but had solo flying privileges revoked by an air training organisation on one occasion after experiencing navigation and airmanship difficulties.
"His overall piloting abilities must therefore be considered to be variable, if not marginal," the report said.
[The drug] would have further reduced his ability to operate the aircraft safely
"This is considered to be a causal factor in this accident since a pilot should not lose control of an aircraft after take-off, even if the engine does stop."
After the crash on 8 July 2007, a toxicology report showed the presence of ecstasy in the pilot's blood, at a concentration of 0.28 milligrams per litre.
"This had probably been taken within a few hours of the flight, and may have impaired both his judgement and his ability to complete complex tasks, which would have further reduced his ability to operate the aircraft safely," the report added.
Jamie Clapp, a pupil at Mangotsfield, South Gloucestershire, was a keen skateboarder.
Hundreds of people attended the funeral of the teenager, who was described as "a popular lad who touched hundreds in his short life".
'Disgust and hatred'
His father, Gordon Clapp, said: "[I feel] disgust and hatred.
"It's unbelievable, because Robert was a good friend of the family, a good mate of Jamie. "For a man of 33 to take my son up in an aircraft under the influence of drugs is beyond belief. If I could, I'd kill him all over again."
Mr Gunter had offered to take Jamie up for a 14th birthday treat and although the youngster first declined because of a dislike of heights, he eventually agreed.
On the day of the flight, Mr Clapp was told to watch out for the plane flying over his house.
"I waited and waited and nothing," he said.
"I gave it no thought, then I'm going past Robert's house and seen police outside, I immediately knew something was wrong, my world just fell apart."
Mr Clapp is currently trying to raise money to set up a skate park for young people in Mangotsfield in memory of his son.
"I've got about £3,000 in cash so far. I'm 66 next birthday and not in the best of health, but it's got to be done," he said.
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