It comes as a House of Lords Select Committee prepares to report by 31 January on whether two air marshals, Sir William Wratten and Sir John Day, were justified in finding gross negligence against the two pilots of Chinook ZD576 which crashed on the Mull of Kintyre killing 29 people.
Although the committee has not completed its report, Lord Craig, former Chief of the Defence Staff and Marshal of the RAF, invited peers and MPs to a briefing in Parliament this week by Wratten.
Craig - who had opposed the setting up of the Lords committee - also invited peers and MPs to consider a briefing paper by Sir Richard Johns and Sir Michael Graydon, now retired from the RAF, who were chiefs of air staff at the time of the accident. Johns and Graydon's paper said that theories of a possible malfunction - for instance that an engine surge caused by a problem with the Chinook's Fadec (full authority digital engine control) software system - were fanciful.
"The select committee has spent much of its time in its hearings examining possible technical failings - these technical hypotheses, as our letter makes clear, are irrelevant."
They add, "We are in no doubt that both the pilots were grossly negligent".
The committee has heard evidence about how technical problems left no obvious trace in the wreckage, possibly involving the Chinook's software-based Fadec fuel control system, could have been a factor in the accident.
A Fadec design flaw caused the near destruction of a Chinook in 1989 and an RAF board of inquiry into the crash of ZD576 was told that, at around the time of the accident, Chinook pilots were confronted with "unforeseen malfunctions of a flight-critical nature which have mainly been associated with the engine control system, Fadec".
Earlier this month, the Air Accidents Investigation Branch told the Lords committee that evidence recovered from the wreckage was "remarkably thin" and did not prove or disprove the normal operation of the Chinook's engines on the approach to the Mull.
By lobbying peers and MPs this week, Johns and Graydon have drawn criticism that they are attempting to pre-empting the findings of the committee.
The tone of their letter suggests that the RAF hierarchy is unlikely to accept the committee's report if it recommends overturning the decision to find the pilots grossly negligent.
Some observers of the controversy say the stage could be set, therefore, for a confrontation between Parliament and the RAF.