The Countess of Mar asked Her Majesty's Government: Whether an aircraft would be considered airworthy if the cockpit and cabin air was being contaminated with pyrolysis products from synthetic jet engine oils and hydraulic fluids. [HL1763]

Lord Davies of Oldham: The Civil Aviation Authority assesses reports of air contamination and takes action, either directly or through the European Aviation Safety Agency, if a threat to aircraft safety is identified. Air contamination would be considered to make an aircraft unairworthy if it was likely to incapacitate the aircraft's flight crew.

To protect the safety of any flight on which an unexpected failure occurs the CAA directs crews to don their oxygen masks whenever they suspect that the crew air supply has been contaminated.

1 November 2005