The influence of fluid contamination on the wear of a number of aircraft dry bearing liners has been examined using a recently developed, accelerated test procedure. It is shown that fluids generally increase wear to an extent depending on the level of stress, the type of fluid and the structure and composition of the liner material. Water is invariably deleterious but, at low stresses, mineral and diester oils can sometimes reduce the wear rate below that obtained in dry conditions. Explanations for the trends observed are deduced from a detailed examination of worn surfaces by X-ray photo-electron spectroscopy (XPS) and scanning electron microscopy (SEM). The relevance of the results to current specification requirements for aircraft dry bearings is discussed, and a number of inadequacies exposed.Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference in San Francisco, California, August 18–21, 1980.