Most people would read this question and immediately think – nope, airplanes do not have steering wheels. However, you might be surprised to learn that passenger aircraft actually do have a steering wheel in the cockpit, for when the plane is ‘driving’ around on the tarmac. How does it work?
Why does an aircraft need a steering wheel?
Aircraft need to perform some pretty tight maneuvers when they land at an airport. They have to navigate off the runway, drive around to the gate, and park in a pretty tight spot. As a result, aircraft designers had to provide a way for big, commercial aircraft to make these maneuvers.
What systems do commercial aircraft use?
Located on larger aircraft is a small wheel (about the size of your hand) called a tiller.
This tiller connects to a hydraulic cog system that pulls a rail back and forth over a cogwheel that attaches to the pillar of the front wheel. Thus, as the cog turns, the wheel can rotate on an axis of 75 degrees each way, from far-right, straight ahead to far left.
As the speed of the aircraft increases (such as taking off a runway), the tiller has less and less direct control of the nose wheel, with the pedals (like the Cessna) having more of an impact. Eventually, the aircraft is going so fast that the pilot uses aerodynamic forces acting on the rudder to turn the plane and does not use the steering tiller.
Once the aircraft takes off, the nose wheel retracts, and the cogs automatically align it back into the neutral straight position.
What happens during aircraft pushback?
You may have also realized that all of the above only works when the engines are pushing the aircraft forward. But how does this system work when the plane needs to reverse?
During pushback by a pushback truck, the front wheel disconnects from the hydraulic system. This allows the wheel to move freely with the pushback truck and to perform movements up to a 95-degree turn.
Once the aircraft is away from the gate, it will start its main engines and move forward. To prevent preflight rudder checks from making the plane swerve left and right as the aircraft moves to the runway, they can be disconnected by the tiller switch. This switch will cut the link between the rudder pedals and the front wheel, making the tiller ‘steering wheel’ the master control.
