Pharmaceutical tycoon Lord Ballyedmond, one of Northern Ireland's wealthiest men, died with the pilots and another employee after the AgustaWestland aircraft came down shortly after take-off from his country house in Gillingham, Norfolk.
His aviation firm, Haughey Air, had issued a writ against the helicopter manufacturer in September last year, after concerns about in-flight mapping systems. AgustaWestland would not comment yesterday.
Chief pilot Carl Dickerson, and co-pilot Lee Hoyle died along with Declan Small, 42, of Mayobridge, Co Down, a foreman on the peer's estate
Lord Ballyedmond, formerly Edward Haughey, chaired Norbrook, the largest privately owned pharmaceutical company in the world.
Air accident investigators were at the scene of the accident involving the AW139 helicopter near the peer's Gillingham Hall.
In February 2012, an inquest heard that in-flight technology systems on board AgustaWestland helicopters should be improved after a crash that killed a friend of the Prince of Wales.
The mapping databases display the height of terrain such as mountains and whether certain areas are available to fly through, but the four-day inquest in Belfast highlighted flaws.
The aircraft flew into the side of a cloud-shrouded mountain in the Mourne range in Co Down in October 2010 as it carried a shooting party back to England.
Friend, Lord Empey, said: "Lord Ballyedmond was one of the most successful entrepreneurs in Northern Ireland and indeed these islands." In January, four crew died on a US military Pave Hawk helicopter which came down inNorfolk.