Parliament's most powerful committee of MPs said today (Thursday) that faulty software could have been a factor in the RAF's worst peacetime air accident.
The Public Accounts Committee (PAC) accused the Ministry of Defence (MoD) of "unwarrantable arrogance" in defending the "unsustainable finding" of pilot error in the 1994 Chinook helicopter crash, which killed 29 people.
The committee's report contradicts more than four years of denials by ministers in both administrations who, briefed by the MoD, have insisted that the Chinook's Full Authority Digital Engine Control (Fadec) software could not have played a part in the crash.
The PAC called on the MoD to set aside the verdict of gross negligence on pilots Rick Cook and Jonathan Tapper. "The evidence provided to the committee points quite clearly to a major miscarriage of natural justice," said PAC chairman David Davis.
The report said, "The faults with the Fadec led to doubts as to the reliability and safety of the aircraft at the time and make it very difficult to rule out categorically a technical fault as at least a contributory cause of [Chinook] ZD576's crash."
MPs said the MoD's acceptance process for the Chinook Mk2 was flawed, as was its outcome.
And MPs warned that engine software on helicopter - the troop transport workhorse of the armed forces - could still not be guaranteed. "The committee does not believe that there was in 1994, or is now, sufficient independent assurance on the performance of the Fadec software.
"The committee simply cannot understand why the department continues to defend the unsustainable finding of gross negligence and recommends it should be set aside," said the report.
In a finding that has implications for all IT procurement, the PAC said reliance on equipment manufacturers to investigate faults in their own systems "undermines the department's ability to act as a truly intelligent customer".
The committee challenged the decision by two air marshals who found the pilots grossly negligent. It said the RAF Board of Inquiry did not satisfy the burden of proof required. At the time of the crash, RAF rules said that deceased aircrew could be found negligent only when there was "absolutely no doubt whatsoever".
Earlier this year prime minister Tony Blair concurred with at least six other ministers when he rejected calls for a new inquiry. He said the Board of Inquiry had found that the Chinook was flown below safety altitude, at speed, in unsuitable weather conditions. "Accordingly the pilots were judged to have been negligent," said Blair.
But the PAC said the Board of Inquiry process was "unsatisfactory", with officers sitting in judgement on the causes of the crash also reporting to those tasked with getting the helicopter quickly into operation.
"At present, the position of reviewing officers on Boards of Inquiry opens the way to allegations of conflicts of interest."
The report contains 11 pages of evidence from Computer Weekly showing that the Chinook's engine software system had been plagued with flight critical problems at the time of the crash - despite assertions by ministers that the software was "not flight-critical".
Main points of the PAC report
Computer Weekly comment
The PAC report vindicates Computer Weekly's three-year campaign to clear the names of flight lieutenants Rick Cook and Jonathan Tapper. It shows that software or mechanical error cannot be ruled out as a cause of the Chinook crash. The gross negligence finding against the dead pilots should be set aside now.
All users of safety-critical IT systems need to ask whether they too would be reliant on the manufacturers to investigate in the case of a catastrophic failure.
And ministers need to ask why the Ministy of Defence continued for five years after the crash to defend its own flawed procurement and safety practice in the face of mounting evidence.
Exclusive: Excerpts from the 1993 EDS-Scicon Report the Defence Select Committee did not see in 1998. Click here
The Computer Weekly evidence to the Public Accounts Committee
Background: Milestones in the Computer Weekly campaign for truth about the causes of the Chinook crash