How do we get a plane in the air without taking off?

Published on 19th May 2017 at 11:33

Gears go up, gears go down. The struts of the landing gear are designed to absorb huge amounts of energy. Here’s a close of up of a Qantas A330 taxiing at Sydney Airport

OK, there a few caveats behind that headline.  But, it’s technically true.  We can lift an Airbus A330 and even larger planes off the ground using giant hydraulic jacks.

Why do we do it? Because it’s the easiest way to test that the landing gear is working correctly.

And how do we do it?

The jacks are positioned under the nose of the aircraft, under the tail and one for each wing.

The aircraft has to be perfectly balanced. Even though it’s only a few inches off the ground, any unsteadiness could have some very expensive and embarrassing results. One of the ways our engineers get the plane balanced is to move the fuel inside the aircraft around, evening out the fuel weight across several different tanks.

You call that a jack? This is a jack. A lot bigger than the jack you keep in the boot of your car but the basic principles are the same.

Once the balance is right, the aircraft is slowly lifted into the air. It’s the same process you’d go through when jacking up your car to change a flat tyre.

In a manoeuvre called a “gear swing”, the landing gear is then lowered and raised several times.

At our Brisbane heavy maintenance base there are areas of the hangar floor which drop down so when the aircraft is jacked up the gear is able to move freely.

After inspecting it closely, our engineers might make a couple of tweaks and checks brakes or tyres, it’s then signed off before the aircraft goes back into service.

The landing gear is tucked away out of sight for the vast majority of your flight, but it’s perfectly engineered for the job it has to do.

Modern landing gears are able to cushion the enormous weight of the aircraft by using cylinder shaped struts which contain a mix of gas and oil.

During the landing, the oil is pushed through tiny holes inside the strut which help absorb the energy of the plane touching down.  That and the combination of nitrogen filled tyres – plus, of course, the skills of our highly trained pilots – means a gentle landing almost every time.

Take a look at the clip below where Carl, an engineer from our Brisbane base, talks through how the landing gear works. Sorry it’s a bit noisy but that’s what it’s like in an aircraft hangar.

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