Campaigners seeking a fatal accident into a crash involving two RAF Tornado jets over the Moray Firth in 2012 are holding talks with the Crown Office.
Three airmen were killed and another seriously injured when the aircraft collided over the Moray Firth off the Caithness coast.
The planes from 15 (Reserve) Sqn at RAF Lossiemouth, in Moray, crashed into the sea during a training flight.
The Crown Office has ruled out holding a fatal accident inquiry (FAI).
But Moray SNP MSP Richard Lochhead, who is involved in the talks, said many issues remained outstanding in the case and should be examined by an inquiry.
In 2015, the Crown Office said the incident had been the subject of a "very detailed" report following an investigation by the Military Aviation Authority (MAA).
All 42 recommendations in the MAA report were accepted by the Ministry of Defence and in the process of being implemented, including installation of collision warning systems, the Crown Office said at the time.
The incident is not covered by new legislation which now provides for mandatory FAIs for the deaths of service personnel.
Each of the Tornados involved in the crash had two crew members on board.
Flt Lt Hywel Poole, 28, who was born in Menai Bridge on Anglesey in North Wales, died in hospital after being airlifted from the scene.
Sqn Ldr Samuel Bailey, 36, from Nottingham, and Flt Lt Adam Sanders, 27, who grew up in Lancashire, were also killed.
A fourth RAF serviceman, Sqd Ldr Paul Evans, survived but was badly injured.