FUME EVENTS

The cabin air supply on most large commercial aircraft is provided using engine bleed air systems. Fume events – abnormal odours, smoke, haze or fumes in the cabin – may arise from various internal or external sources, and some are due to contamination of the bleed air supply, for example as a result of a failure of an oil seal in the engine. In recent years concerns have been expressed about possible adverse health effects of exposure to contaminants in cabin air. More specifically, the term “fume event” is used to refer to a potentially toxic environment created by contaminated bleed air used to pressurize and ventilate aircraft cockpit and cabins.

• An oil spill in front of the landing gear may indicate a leak in the hydraulic system. This is hazardous as some of the fluid may enter the Bleed Air system, which may lead to a fume event.
• Purple trails of fluid from gaps in the wing or tail surfaces may indicate a leak in the hydraulic system. However, it is unlikely that, in this locations, the hydraulic fluid will contaminate the Bleed Air system.
• Black stain around the engine exhaust pipe is just water mixed with carbon in the exhaust pipe. Water usually comes out when the engine is not hot enough (i.e. when starting it). So the liquid water drips out of exhaust with the carbon mixed in it making it black.