Government auditors will report tomorrow (Friday) that defence staff put into operational service a fleet of Chinook helicopters with safety-critical software that had not been approved by the MoD's own airworthiness assessors.
The National Audit Office report will not mention the fatal Chinook crash on the Mull of Kintyre in 1994, which some specialists believe involved software problems.
The 1994 Chinook crash killed 29 people.
But the report summarises the concerns about the helicopter's Fadec engine control software, as expressed by the MoD's software specialists at Boscombe Down.
Specialists found that the Fadec software was unverifiable and, in their view, not fit for purpose.
They also criticised the amount of testing of the Fadec system by the software manufacturer.
The Audit Office report raises issues at the heart of Computer Weekly's campaign for a new inquiry.
In November 1993 the MoD and the RAF released the upgraded Chinook Mk2 into service, despite Boscombe Down's concern. There was no evidence that software caused the crash in June 1994 and the accident was blamed on the pilots. A report by an RAF Board of Inquiry, however, found that the pilots could have faced technical problems that left no physical trace.
Separately, an influential US report has added weight to these concerns by concluding that software problems could leave no physical evidence in the wreckage.