My airplane has a nosewheel that is steerable through the rudder pedals, and two main wheels, each of which has a disc brake actuated by pressing on the top of the corresponding hinged rudder pedal. That's a conventional arrangement, except that it's not - in general aviation a conventional gear means a tailwheel configuration. Tailwheels were the convention before World War II but, obviously, the lexicon hasn't caught up to the fact that the convention today is a tricycle landing gear.
It would be a mistake, however, to assume that once you've mastered ground handling in one type of nosewheel-configured airplane, you can drive any other nosewheel model with confidence. Different airplanes exhibit different nosewheel design and manufacturing philosophies. Learning how these differences affect ground handling is an important element of transitioning into an airplane that is new to you. In fact, much of the instructional time spent transitioning into some airplanes may be devoted to ground handling.
The poster child for "different" ground handling is the Grumman line of singles (also known as American Aviation, American General, and Gulfstream American, depending on the model and vintage) - the Tiger, Cheetah, Traveler, and various two-place AA-1 models. They drive differently because the nosewheel is not steerable through the rudder pedals. Instead, these aircraft have a castoring nosewheel that swivels freely at the end of a curved, tubular-steel nosewheel strut. You taxi-steer by pressing on one of the brake pedals. It takes some practice to steer using just the toe brakes - a technique called differential braking - instead of also pushing the rudder pedals to turn the nosewheel, but it's an easily mastered skill.
Taxiing sometimes requires use of both nosewheel steering - if you've got it - and braking. One instance when both might be required is using a high-speed runway exit to comply with a controller's request to expedite clearing the runway due to landing traffic. Toe brakes make it a lot easier to coordinate braking and nosewheel steering because the brake pedals are mounted on the rudder pedal bars.
Not every airplane has toe brakes, however. Some older Piper singles have a single brake bar, a long handle hanging down from under the instrument panel near the center pedestal. Pulling on the bar applies equal pressure to both the left and right main-wheel brakes. In other words, there is no differential braking available to help in making tight turns. It takes practice to perfect the technique of making sharp turns at slow taxi speeds while applying the brakes.
Differences in steering and braking configuration and technique really come into play in tailwheel aircraft. In fact, transitioning into a taildragger is all about coming to grips with ground handling.
Some tailwheel aircraft have a tailwheel that is steerable through the rudder pedals. Others have a castoring tailwheel that, like the Grumman singles, calls for differential braking to steer on the ground. Most have toe brakes similar to their nosewheel counterparts, but some, such as the Piper J-3, use heel brakes. It's just another interesting quirk to adapt to when transitioning into a Cub.
Regardless of brake and steering configurations, tailwheel airplanes behave differently in ground handling than nosewheel models because the center of gravity is located behind the main wheels. That makes it less directionally stable on the ground than a nosewheel airplane.
Misuse the brakes in a nosewheel airplane and you'll probably get a jerky, uncomfortable ride during the taxi to and from the runway. Heavy braking on the landing roll could cause one or both main wheels to lock up, leading to a flat-spotted tire or two. A worst-case heavy braking scenario on the landing roll has the airplane wheelbarrowing - rolling on the nosewheel only, with the main wheels off the runway.
Braking is a more precise skill when the third wheel is at the rear of the fuselage. Taxiing calls for real finesse on the brakes to avoid sharp turns that could lead to a ground loop, or sudden stops that could cause the tail to rise, possibly leading to a prop strike. When there is sufficient airflow over the rudder, it becomes the primary means of steering while taxiing, especially during the takeoff and landing roll.
Paying respectful attention to ground handling techniques pays dividends in terms of reducing the risk of suffering an incident, less wear and tear on brakes and other components, and impressing passengers with a smooth ride to and from the runway.
Regardless of the type of airplane we fly, certain ground handling procedures are universal:
- Test the brakes as you begin to move away from your parking spot, before you reach normal taxiing speed. You can drag the brakes momentarily - apply slight pressure so the airplane begins to slow but does not stop-to clean off the light coating of rust that typically appears on rotor disks when the airplane sits for a few days.
- Make taxi turns by reducing throttle first, then braking, then turning. Braking to turn without reducing power just uses up the brakes faster.
- Remind yourself before starting the takeoff roll to have only the balls of your feet resting on the rudder pedals. That prevents you from inadvertently pushing on the brake portion of the pedal during the takeoff roll. The same goes for final approach.
Like the drive to and from the airport, the short drive to and from the runway can be the most hazardous portion of the flight. It pays to be cautious whenever we're on the road, even when the road is a taxiway.
Related Articles
