Angus Robertson, the SNP leader at Westminster whose constituency includes RAF Lossiemouth, has written to Frank Mulholland, the Lord Advocate, seeking clarification.
Last month, the Ministry of Defence admitted that a potential collision warning system was identified but not installed four years before the mid-air crash. It was not until three months after the incident that such a system, costing £53 million, was approved; it is due to become operational by the end of this year.
Last year, an investigation by the Military Aviation Authority was completed and it is now for the Procurator Fiscal to decide whether there should be a formal inquiry.
In his letter to Mr Mulholland, the MP for Moray said: "The prospect of a fatal accident inquiry into the tragic fatal collision of two Tornados above the Moray Firth on July 3, 2012 has been repeatedly raised with me. Please could you advise me when a decision will be made as to whether a Fatal Accident Inquiry will be conducted?"