Dr. Margaret Ann Rous, a 37-year-old GP, and her 28-year-old husband David Rous, an engineer, were killed when a light aircraft struck the hillside at Glen Etive in Argyll on April 4 last year.
They had been en route from Dundee to Tiree to spend the Easter weekend with Dr. Rous’ family.
Today, an Air Accidents Investigation Branch report into crash said investigators had uncovered “no specific cause” for the tragedy.
However, it added that it appeared Mr Rous, who was piloting the Piper Cherokee, had suffered “some form of spatial disorientation” and that the accident “followed a loss of control, possibly in cloud”.
Despite obtaining his private pilot's license less than a year earlier, in June 2014, Mr Rous was considered to have "above average" skills and had accumulated more than 130 flying hours by the time of the crash.
Visibility was deteriorating as the plane flew over Argyll and investigators believe that Mr Rous had realized it would not be possible to continue to Tiree and had decided to return to Dundee instead, although he did not communicate this to air traffic control.
Mr. Rous commenced a "controlled, and initially level, right turn" over Glen Etive but this quickly "developed into a spiral dive, consistent with some sort of spatial disorientation".
Around 40 seconds later the aircraft struck the slopes of Beinn nan Lus in a 45-degree nosedive, at high speed. Both Mr. and Dr. Rous were killed instantly
The report states: "It is likely that the aircraft, prior to or during the right turn, had entered cloud or that the pilot had experienced some loss of, or false, visual horizon. The gentle right turn is likely to have been the commencement of a deliberate turn back to the east or from carrying out some cockpit activity...this in turn may have led to him becoming disorientated."
Investigators added that the poor weather may also have caused airframe icing, which could also be a factor in the crash.
Meanwhile, new safety measures are to be introduced at Dundee Airport after two people died in a small plane crash.
Andrew Thompson, 37, who had previously lived in Bearsden, near Glasgow, and John MacKinnon, 53, from Ross-shire, died in May 2015 when the G-Rick Beech Baron aircraft crashed near the village of Abernyte in Perthshire.
There was low cloud and heavy rain in the area at the time, meaning the pilot had to fly primarily by reference to instruments. An AAIB report concluded a mix-up of distances between the onboard GPS system - calculated based on the airport's non directional radio beacon (NDB) and distance measuring equipment from the runway caused the pilot to start his descent too early.
The airport operator, Highlands and Islands Airports (HIAL), has commissioned a safety survey in light of the findings.
NTSB Identification: CEN15WA191
14 CFR Non-U.S., Non-Commercial
Accident occurred Saturday, April 04, 2015 in Loch Etive, United Kingdom
Aircraft: PIPER AIRCRAFT CORPORATION PIPER PA-28-140, registration:
Injuries: 2 Fatal.
The foreign authority was the source of this information.
On April 4, 2015, at an unknown time, a United Kingdom registered Piper PA-28-140 airplane, G-BHXK,impacted mountainous terrain near Lock Etive, Oban, Argyll, and Bute, United Kingdom.The two occupants were fatally injured.
The investigation is under the jurisdiction of the government of the United Kingdom. Further information may be obtained from:
Air Accidents Investigation Branch
GU11 2HH, United Kingdom