The Countess of Mar asked Her Majesty's Government: Why filters are not fitted to
commercial aircraft to prevent crews and passengers from being exposed to
pyrolysis products from synthetic jet engine oils and hydraulic fluids during a
contaminated air event. [HL1762]
Lord Davies of
Oldham: Filters are not required on commercial aircraft because European
airworthiness regulations already require aircraft ventilation systems to be
designed to supply air to an acceptable standard, free from harmful or
hazardous concentrations of gases or vapours.
This is confirmed at the aircraft initial certification and thereafter
each commercial aeroplane in the United Kingdom is subject to rigorous
scheduled maintenance to ensure that the intended standards are maintained.
To protect the safety of any flight
on which an unexpected failure occurs the CAA has directed crews to don their
oxygen masks whenever they suspect that the crew air supply has been
contaminated.
October 2005