A helicopter crash in which five family members were killed happened after the pilot failed to turn around when entering low cloud, accident investigators said.
Three brothers and two of their wives died in the crash in mountains in Snowdonia, North Wales, on March 29 last year.
Pilot Kevin Burke, 56 and his wife Ruth, 49, of Hulcote, were among the victims.
Donald Burke, 55, his wife Sharon, 48, and brother Barry, 51, who also lived in the Milton Keynes area, also died.
They were on their way to Dublin for a party following the confirmation of another young relative.
The Air Accidents Investigation Branch found that the pilot “had the option to turn back, divert or land” when he entered an area of poor visibility.
An Air Accidents Investigation Branch (AAIB) report into the crash revealed the weather had deteriorated significantly in Snowdonia after the aircraft took off.
It said the Twin Squirrel helicopter had descended to 2,060ft (627m) and hit the east side of the Rhinog Fawr mountain, in a remote area between Trawsfynydd and Harlech, just before noon.
A witness in the Coed Brenin forest saw the helicopter pass overhead before it went into clouds.
The privately owned Twin Squirrel aircraft struck the side of Rhinog Fawr Mountain at an altitude of 2,000 feet.
A system which alerts pilots when they are approaching high terrain is available for the GPS equipment used by the helicopter, but was not fitted.
“There was no other means of warning the pilot of the rising ground,” accident investigators said.
The bodies of the victims were found with the wreckage near Trawsfynydd.
The AAIB report found no defects in the aircraft controls and records showed it had been regularly maintained.
Businessman Kevin Burke was described as an experienced private helicopter pilot who had renewed his licence proficiency check in August 2016.
The report concluded: “The accident occurred after the helicopter entered cloud while descending. The pilot did not carry out a 180 degree turn away from the rising ground and probably did not regain VMC before impact with the side of the mountain.”
An inquest into their deaths was opened and adjourned pending the outcome of the AAIB inquiry.