Mind the jet blast

Published on 5th November 2018 at 16:43

Did you know the hot compressed air expelled from a jet engine when it’s on the ground can travel up to 170km/h, that’s equivalent to what you’d experience during a Category 4 Cyclone.

These huge gusts of wind, aka jet blasts, give aircraft thrust. So while it can propel an aircraft through the skies, on the ground it can be an occupational hazard for airport workers as well as other aircraft.

Stand clear: This warning appears on the outside of the engine.

That’s why airport taxiways and parking bays are designed to provide enough space for aircraft to manoeuvre safely, because even at low power, a gust of air from an engine can cause damage.

Around some terminals you will see curved walls or fences. These are known as blast barriers and their shape directs the blast of engine air upwards eliminating any potential risk.

Jet blast can be felt well over 100 metres from the rear of an engine, so the barriers are an effective way to ensure people, equipment and other planes are kept safe.

If you’re an eagle-eyed plane spotter, at some airports you’ll see signs on the sides of taxiways with the words, “caution your blast” which is a short way of saying, please avoid powering up too much in this area as your jet blast could pose a risk.

There are times when we need to run the engines at full power without taking off, usually after a new engine is fitted or when maintenance has been undertaken.

At our Sydney Jetbase, we have two special engine run bays on the right of the main runway’s northern end where our engines can safely run full throttle.

They’re easily recognisable thanks to the movable jet blast fences which sit on a metal rail, so they can be dragged behind the engines when the aircraft is powered up.

Before the engines are tested, we make sure the aircraft’s park brake is applied and heavy chocks are put in place to stop the force of the jet blast shifting the aircraft.

Have a look at one of our A380s completing an engine run below.

And remember, always mind the jet blast.