Chinook software probe due

Members of Parliament (MPs) are expected to investigate the air-worthiness of the engine control software on the type of Chinook helicopter that crashed on the Mull of Kintyre in 1994, killing 29 people.

The enquiry, to be staged by the Public Accounts Committee (PAC), is expected to question whether the Chinook should have been allowed to fly with flawed safety-critical software.

The PAC’s investigation was triggered by a National Audit Office report into the Ministry of Defence’s acceptance into service of a range of projects and systems.

At the centre of the Mull of Kintyre crash is the role played by the helicopter’s two Special Forces pilots.

A subsequent RAF board of enquiry judged both to have been grossly negligent, largely because no evidence of technical evidence was found in the wreckage of the aircraft.

However, many computer and helicopter specialists believe that software could have played a part in the accident without leaving any physical trace.

In the weeks before the crash, a new software-based Full Authority Digital Engine Control system (Fadec), which manages the operation of the helicopter’s engines, was known to have malfunctioned.

As part of a year-long investigation, Computer Weekly has catalogued several instances where pilots reported unexpected behaviour in the engines and false warnings of engine failure by cockpit control instruments.

Fadec is expected to be of particular interest for the PAC because auditors found that the MoD's own airworthiness assessors had refused to endorse the software. The assessors had recommended that the software be rewritten.