James Ian Stanley Innes (59) and Andrew John Innes (30) were killed when the Hughes 500D helicopter in which they were travelling crashed near Price, Utah, in the United States, on Saturday (US time).
The deaths came 10 years after the eldest son, Daniel Innes, died in a helicopter crash in Mexico in 1998.
James Innes' brother David died at age 22 when he was hit by an aircraft while driving a tractor as he mowed Taieri airfield in 1979.
The latest tragedy has devastated Auckland surveying company director Mingo Innes and his mother, Belinda, of Wanaka.
Mr Innes said he was struggling to come to terms with the deaths of his father and brother.
The crash brought back memories of when his eldest brother died.
"When my aunt rang me on Saturday, I thought 'This is unbelievable'," he said yesterday.
Mr Innes moved from Wanaka to Auckland two months ago with wife Susan and infant daughter Rose.
He returned to the resort yesterday to be with his mother.
His mother was "holding up. She is a strong woman".
However, the double blow of her son and former husband's deaths were extremely hard.
Mr Innes is the middle brother of Daniel and Andrew and their deaths had left him as their mother's sole remaining son.
The family were last together in March, when Andrew married his American bride Season at a ceremony in Wanaka.
"I really feel for her, and also my dad's partner Debbi," Mr Innes said.
James and Andrew Innes were returning from a fishing trip with Idaho Falls man George McDaniel (40) and had stopped to refuel at an airport in Price, Carbon County, Utah.
The helicopter, piloted by James Innes, reportedly crashed soon after take-off from Price.
Little of the aircraft remained intact, with the only recognisable parts a tail rotor and some of the main rotor blades.
Mr Innes said he was told a civil aviation investigation would take some time to determine the cause of the crash.
The Salt Lake Tribune newspaper reported the crash was the second at the small airfield in 13 months.
A local helicopter pilot said flying in and around Price was challenging because high temperatures and altitude created thin air.
Price airport is 1750m above sea level.
The Innes family were past owners of Haldon Station, in the Mackenzie Country, where James Innes established himself as a deer farming industry leader.
In 1991, he travelled to Utah to establish Western Slope Helicopters, an animal recovery operation based out of Salt Lake City.
The family had moved first to Queenstown in 1991, before settling in Wanaka in 1994.
Mr and Mrs Innes separated about 1995.
Mingo Innes said his father was a charismatic figure and a successful businessman who had an positive outlook on life.
Andrew recently joined his father's business operation in Salt Lake City, and had moved with his wife from Chicago, where he worked as a financial and marketing consultant.
His older brother, Dan, died aged 26, in 1998 while flying in Mexico.
He had been rounding up bighorn sheep as part of a contract for the family-owned helicopter animal recovery operation.
The family intended to bring the ashes of his father and brother back to New Zealand for burial, after a US cremation ceremony, Mr Innes said.
A private memorial service is planned in Wanaka for Andrew, with a joint family service for the two men in Christchurch at a yet-to-be-arranged date.
