Published Monday, 20 February 2012
Agusta helicopter crashed near Leitrim Lodge. (© Pacemaker)
Charles Stisted, Ian Wooldridge and pilot Anthony Smith died when the craft came down in the Mourne Mountains, Co Down, in October 2010.
At the Belfast inquest on Monday, a lawyer for the inquiry said there was a ground proximity warning system on board.
However he added that it was not required to be used and the alerts would have been a nuisance to those inside the helicopter.
Ronan Daly said: "It was not actually in use.
"It was not the requirement for a helicopter to operate that it should be using the system and the alerts that the system would (produce) could be regarded as a nuisance to those on board."
The men were visiting Northern Ireland when the crash happened.
One of them, 47-year-old Mr Stisted, was a personal friend of the Prince of Wales.
Mr Wooldridge, 52, was a construction company businessman and pilot Mr Smith, 63, was formerly of the RAF and army with service in NI.
The flight was on its way back to England after the men attended a shooting party at an estate in Co Tyrone.
© UTV News