Welcome back to our Word of the Week!

Every week, we look together at a word that is either interesting, funny or mysterious and that appeals to all of us in the aviation community.

No worries, there is nothing medical about the word of this week. We are not in a horror movie, and nobody is going to bleed. Not even air.

Bleed Air: Compressed air taken from the compressor stage of a gas turbine upstream of its fuel-burning sections.

So, as you may have guessed, bleed air comes from jet engines or turbine engines.

Bleed air is in fact compressed air taken from the engine to power a number a specific applications in the aircraft.

Bleed air is usually used in the following systems:

  • pressurisation
  • air conditioning
  • engine start
  • wing and engine anti-ice systems
  • water system pressurisation
  • hydraulic system reservoir pressurisation

The expression “bleed air” comes from the fact that the compressed air is “bled” from the compressor section of the engine(s) and APU, and then redistributed to various parts of the aircraft through a network of ducts, valves and regulators

A simplified illustration of bleed air