Video report by ITV News reporter Ben Chapman
Conservative peer Lord Ballyedmond, who was killed in a helicopter crash with three others - all now named - recently raised safety concerns with the aircraft's manufacturers.
Two pilots killed in the crash in Norfolk have been named by sources as Carl Dickerson, chief pilot at Haughey Air Ltd, and Lee Hoyle, a co-pilot at the company - which was owned by the entrepreneur who was one of the richest men in Northern Ireland.
The fourth man who died was named locally as Declan Small, 42, a foreman who worked for Lord Ballyedmond. He came from Mayobridge, Co Down.
Lord Ballyedmond, known as Edward Haughey until he was made a life peer in 2004, was chairman of Norbrook, the largest privately owned pharmaceutical company in the world.
The 70 year old Irish peer was the founding Chairman and CEO of Norbrook Pharmaceuticals, and also one of the richest men in Northern Ireland. He leaves behind a wife and three children.
Norbrook released this statement:
Norbrook management and staff also mourn the loss of their friends and colleagues Declan Small (Site Foreman), Captain Carl Dickerson (Pilot) and Captain Lee Hoyle (Pilot).
Our thoughts are with the immediate families and friends of the deceased who have requested privacy at this difficult time.
A police spokesmen later said that police, fire officers and AAIB investigators have worked throughout the day to enable the recovery of the deceased from the site, and are now "satisfied that primacy for the investigation can sit with the AAIB."
Prime Minister David Cameron also said in a statement:
"Lord Ballyedmond was a towering figure in Northern Irish business life, and passionate about peace and good relations north and south, east and west.
"He was a larger than life figure who was a great supporter of the Conservative party and a good friend to me."
Suffolk Police say the helicopter took off from Gillingham Hall and was heading towards Ireland.
James Tuttle, 41-year-old, who lives in nearby Geldeston, saw the helicopter come down.
– JAMES TUTTLE, EYE WITNESS
We used to see him coming and going in his helicopter from our back garden all the time.
At about 7pm we noticed the helicopter coming in very low and at an unusual 45-degree angle.
We didn't hear any bang or explosion, it just seemed to be flying in a strange way.
The fog wasn't bad at the time, just patchy, it only got worse about an hour after the crash happened.
Air accident investigators have now begun to work to find a cause of the crash.