James Healy-Pratt is representing the family of the lord - who was one of Northern Ireland's richest men - at an inquest into the deaths in Norfolk.
He said the family believed the crash, in March 2014, was "preventable".
A crash report said the crew was unhappy about taking off in heavy fog.
The inquest into the deaths in the crash, which happened close to Lord Ballyedmond's home in Gillingham, near Beccles, is due to start on Tuesday.
The pilots of the Agusta AW139 G-LBAL helicopter, 36-year-old Capt Carl Dickerson, and Capt Lee Hoyle, 45, were killed instantly along with Lord Ballyedmond, 70, and his 42-year-old foreman, Declan Small, from Mayobridge, County Down.
Read more on this story and others from Norfolk.
An Air Accidents Investigation Branch (AAIB) said the crew were unhappy about taking off in heavy fog.
The report said the take-off from the peer's estate, Gillingham Hall, would not have been allowed from a licensed aerodrome.
It found the crew lacked visual cues, formal training and procedures to fly in the conditions on board.
Mr Healy-Pratt, of Stewarts Law and himself a qualified helicopter pilot, is also representing the Small family.
"Lord Ballyedmond entrusted the safety of his employee's life and also his own to the pilots on that foggy evening in March 2014, in a sophisticated helicopter full of safety equipment that Lord Ballyedmond had specifically chosen because of his commitment to crew and passenger safety," he said.
"The aviation insurers for both pilots this week have agreed not to contest responsibility for the death of Lord Ballyedmond or Declan Small.
"Both families expect the inquest to deliver clarity and truth about the causes of the crash, and... ensure that further innocent lives are not lost in similar preventable accidents.
"One possible recommendation is that, after significant delay, the Civil Aviation Authority should require pilots of privately-owned helicopters to follow the same requirements as pilots of commercially operated helicopters, which might well have prevented this accident."
Insurers for pilots of a helicopter that crashed killing them and two passengers including Lord Ballyedmond, are not contesting responsibility, a solicitor has said.