How does landing gear system work

Diminished forward visibility when the tailwheel is on or near the ground is another disadvantage of tailwheel landing gear airplanes. Specific training is required to operate tailwheel airplanes. When the third wheel is located on the nose, it is called a nosewheel, and the design is referred to as a tricycle gear. It has the following advantages compared to the conventional type:. A steerable nosewheel or tailwheel permits the airplane to be controlled throughout all operations while on the ground.

Most aircraft are steered by moving the rudder pedals, whether nosewheel or tailwheel. Airplane brakes are located on the main wheels and are applied by either a hand control or by foot pedals toe or heel. Foot pedals operate independently and allow for differential braking, i.

Landing gear can also be classified as either fixed or retractable. Fixed landing gear always remains extended and has the advantage of simplicity combined with low maintenance.

Retractable landing gear is designed to streamline the airplane reduce the drag by allowing the landing gear to be stowed inside the structure during cruising flight. Fixed landing gear is common with slow e. Heavier aircraft require more complex landing gear. These consist of multiple wheels and sometimes the MLG is made of more than two assemblies. Some large cargo aircraft, e. Retractable landing gear is normally powered by the hydraulic system.

The Boeing has four separate hydraulic systems, for example. As the gear is raised, it will often shorten to take up less space in the fuselage compartment. On the A this is achieved by retracting the shock absorbers in the landing gear strut.

The gear is lowered for landing once the airspeed reaches a designated level this is knots on the A, for example. Doing so before this could damage the gear, and it is usually prevented. Lowering is controlled by the same dual computer system. There is a further backup system in case the hydraulic systems fail.

On the A, this is gravity-assisted, using electromagnets. Older aircraft may even have had a manual handle to lower the gear. Ensuring that the gear is lowered correctly and locked before landing has always been vital. These days, this is indicated by the computer unit using lights in the cockpit. There is usually a secondary, independent system indicating this as well.

It is not that long ago that it was also possible to check this visually. Many older Boeing aircraft, as described on The Boeing Technical Site , have a viewing periscope in the fuselage above the main landing gear. This was discontinued from the NG Series when an independent indicator backup system was introduced. Despite improvements in technology and numerous backup systems, emergency incidents involving the landing gear do happen.

With so many moving parts and hydraulic systems in play, risk remains. Fortunately, there are cases of aircraft landing successfully despite problems. Simple Flying regularly reports aircraft incidents involving landing gears. In March , for example, a Virgin Atlantic Airbus A was forced to return to London Heathrow after its landing gear failed to retract. And just the month before that, the main landing gear collapsed on an Icelandair Boeing at Keflavik International Airport.

Some prominent significant emergencies include a JetBlue Airbus A in , which landed at Los Angeles International Airport with a nose gear stuck at the wrong angle.

The landing gear is a critical part of all aircraft, but not something we often write about. Feel free to share or discuss any different systems, or interesting facts you are aware of, in the comments. Journalist - With almost a decade of experience in the publishing sphere, Justin has built up a deep understanding of the issues facing aviation today.

With a keen interest in route development, new aircraft, and loyalty, his extensive travels with airlines such as British Airways and Cathay Pacific has given him profound direct comprehension of industry matters. Justin Hayward Journalist - With almost a decade of experience in the publishing sphere, Justin has built up a deep understanding of the issues facing aviation today.

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