Normalisation of Deviance

 Charles Haddon-Cave's Nimrod Review: An Independent Review into the Broader Issues Surrounding the Loss of the RAF Nimrod MR2 Aircraft XV230 in Afghanistan in 2006 was laid before Parliament and published by the Stationery Office on 28 October. Two days later it was out of print. The Review was not a Public Inquiry with statutory powers. It sat in Ministry of Defence premises. Some staff were seconded from the ministry. But its conclusions, and its naming of the incompetent, leave no doubts about its independence.

The accident to XV230 was avoidable.

My report identifies manifold shortcomings in the UK airworthiness and in-service support regime, and reveals matters which are as surprising as they are disturbing.

The Nimrod Safety Case took a total of nearly four years to produce (April 2001 to March 2005) and cost in excess of £400,000… [It] was a lamentable job from start to finish. It was riddled with errors. It missed the key dangers. Its production is a story of incompetence, complacency and cynicism.

The Nimrod Safety Case process was fatally undermined by a general malaise: a widespread assumption by those involved that the Nimrod was 'safe anyway' (because it had successfully flown for 30 years).

Haddon-Cave looked at the organisational causes of other major accidents, notably the loss of the Space Shuttle Columbia, and found strong similarities. Both had long incubation periods. Strong signals of problems had been identified and recorded, but analysed away. Diane Vaughan in her study of the Challenger Space Shuttle disaster coined the phrase 'normalisation of deviance' to categorise this phenomenon: for Challenger it was a fault in the O-rings in the solid booster rockets; for Columbia it was foam insulation coming loose. These were judged – wrongly – to be acceptable risks.

The normalisation of deviance is not peculiar to aviation or space travel. The categorisation of escalator fires on the London Underground as 'smoulderings' before the King's Cross fire is another example.

I chaired a public inquiry into the 2005 South Wales E.coli O157 outbreak (157 cases, mostly in schoolchildren, with one death). There was a normalisation of deviance. In 1994 the abattoir that supplied contaminated meat to the butcher responsible for the outbreak had an unannounced independent inspection. Its hygiene scored 11 out of 100, the worst ever recorded in Britain (scores less than 66 were deemed to be unacceptably low). A recommendation went up the line that it should be closed. But it was not. Months and years went past. There was no significant improvement. Deficiencies were recorded, but not rectified. The same independent inspector visited in April 2005. He concluded that the problems he found looked remarkably similar to those in 1994. The outbreak occurred in September. Like the MOD, the Meat Hygiene Service had failed.

Food hygiene is assessed using a system known as HACCP: hazard analysis and critical control points. Haddon-Cave's description of what he found with Nimrod – a lamentable job, riddled with errors, missing the key dangers – applies to the butcher's perfectly. His HACCP said things that were untrue (for example that the butcher had a 'number of quality awards for excellent service and hygiene standards'), it made claims that were physically impossible to achieve (about the speed of cooling of meat), and it did not consider the processing of bought-in products (errors in their handling caused the outbreak). The environmental health officers who inspected the butcher failed to spot these deficiencies, just like the wing commander (since promoted to air commodore) who signed off the Nimrod safety case, having 'failed to check carefully and query what he was signing'.