TW.2
Ground Handling, Taxi, and the Ground Loop
Taxi an airplane you cannot see over, position the controls for the wind, and recognize and stop a swerve before it becomes a ground loop.
References: FAA-H-8083-3 (AFH ch. 14)
Quick Review
Conversational Q&A — quiz yourself before the oral.
The steering mechanism operates along with the rudder and remains engaged through an arc of about 30° each side of center. Beyond that limit the tailwheel breaks free and becomes full swiveling — in full swivel the airplane can be pivoted within its own length (AFH ch 14).
Use the steerable tailwheel for normal turns and keep your feet off the brake pedals to avoid unnecessary brake wear (AFH ch 14).
The first thing you do is test the brakes:
- Apply power to start the airplane moving slowly forward.
- Retard the throttle while applying smooth, simultaneous pressure to both brakes.
- If braking action is unsatisfactory, shut the engine down immediately (AFH ch 14).
Apply rudder in the desired direction of turn and use whatever power or brake is necessary to control taxi speed (AFH ch 14).
At very low taxi speeds, directional response is sluggish — surface friction on the tailwheel inhibits inputs through the steering springs. At normal taxi speeds, rudder inputs alone should start and stop most turns (AFH ch 14).
- Aileron: stick held into the wind. The upwind wing can easily be lifted by gusts or strong winds unless the ailerons are positioned to "kill" lift on that side.
- Elevator: usually full back, to add downward pressure on the tailwheel assembly and improve steering response.
- Exception: in a strong quartering headwind a wing could lift, so the elevator may be held closer to neutral (AFH ch 14).
The aileron rule is the same one you learned in a trainer — what's added is the tailwheel's vulnerability created by the fuselage pitch attitude.
Aileron: stick away from the crosswind — left aileron in a right quartering tailwind (AFH ch 14).
Elevator: it depends on wind strength; this is the one that isn't a simple rule.
The nose-high fuselage angle actually reduces the wind's tendency to lift either wing in a tailwind. But the basic vulnerability to surface winds makes it essential to know the wind direction at all times (AFH ch 14).
Standard teaching says full forward stick in any tailwind, for two reasons: a tailwind striking a full-down elevator increases downward pressure on the tailwheel, and — equally important — if the elevator stayed deflected up, a strong tailwind can get under the control surface and lift the tail, with unfortunate consequences for the propeller and engine (AFH ch 14).
But forward stick is not appropriate in light winds. Propeller wash in even lightly-powered airplanes usually overcomes a light tailwind, producing a net headwind over the tail — so back stick does more for directional control. If in doubt, sample the wind as you taxi and put the elevator where it does the most good (AFH ch 14).
Alternately turn the nose from one side to the other (zigzag) or make a series of short S-turns, done slowly, smoothly, positively, and cautiously (AFH ch 14).
And in an airplane that's completely blind ahead, start every taxi movement with a small turn — to be sure nothing has positioned itself directly under your nose while you were heads-down getting ready (AFH ch 14).
An uncontrolled turn during ground operations that may occur during taxi, takeoff, or the after-landing roll (AFH ch 14).
Ground loops start with a swerve that is allowed to continue for too long. The swerve may come from a side-load on landing, a taxi turn started with too much groundspeed, overcorrection, or even an uneven surface or soft spot that retards one main wheel (AFH ch 14).
Because of the inbuilt instability, the forces that lead to a ground loop accumulate as the angle between the fuselage and inertia (acting from the CG) increases (AFH ch 14).
It's a positive feedback loop: more yaw angle produces more force producing more yaw. If allowed to develop, the forces may become great enough to tip the airplane to the outside of the turn until one wing strikes the ground (AFH ch 14).
- Counter any swerve with firm rudder input.
- In stronger swerves, differential braking is essential — tailwheel steering alone proves inadequate.
- As the correction begins to take effect, remove the rudder and braking inputs promptly — otherwise you start another departure in the opposite direction (AFH ch 14).
Step 3 is the one pilots skip, and it's why oscillations build.
The combination of inertia acting on the CG and ground friction of the main wheels may cause the airplane to tip enough for the outside wingtip to contact the ground, and may even impose a sideward force that could collapse one landing gear leg (AFH ch 14).
In general, this combination is eliminated by landing straight and avoiding turns at higher than normal running speed (AFH ch 14).
Slide your toes or feet up from the rudder pedals to the brake pedals (or apply heel pressure in heel-brake airplanes).
Critical detail: if you're holding rudder pressure when braking is needed, do not release that pressure as your feet slide up — control may be lost before the brakes can be applied (AFH ch 14). Apply brakes smoothly and evenly, and avoid overcontrolling (AFH ch 14).
Deep Dive
The taxi rhythm
Transitioning pilots almost always struggle with the first taxi, and it's rarely a skill problem — it's a model problem. A nose-wheel taxi turn is a steady-state input: you hold rudder and the airplane holds the turn. A tailwheel taxi turn is three discrete events.
At very low taxi speeds, surface friction acting on the tailwheel inhibits the inputs coming through the steering springs, so response is sluggish. At normal taxi speeds, rudder inputs alone are enough to start and stop most turns (AFH ch 14).
The trap is calibrating your feet on the sluggish low-speed response and then carrying that habit into higher-speed rolling — where the same input is now oversized.
Wind at your back is the sneaky one
The AFH treats elevator position in a tailwind as genuinely conditional, and it's worth understanding why rather than memorizing a rule you'll misapply.
Two forces compete over your horizontal tail: the ambient tailwind, and the propeller slipstream blowing aft. In a strong tailwind the ambient wind wins — a raised elevator becomes a lifting surface a strong tailwind can get under, so full forward stick is essential to protect the tail, the prop, and the engine. In a light tailwind the slipstream wins, producing a net headwind over the tail — so back stick loads the tailwheel and buys you steering.
The AFH's practical instruction is not a rule at all: sample the wind as you taxi and position the elevator where it will do the most good (AFH ch 14).
They're the solution because in stronger swerves differential braking is essential — tailwheel steering alone proves inadequate to stop the divergence (AFH ch 14).
They're a hazard because braking inputs held after the correction takes effect start a departure in the opposite direction, and because caution should be exercised when applying brakes to avoid overcontrolling (AFH ch 14). Firm, brief, and off — not firm and held.
Apply aileron control toward the wing that is rising to lower it. The amount required depends on speed, because as forward speed decreases the ailerons become less effective (AFH ch 14).
So the input isn't fixed — it grows as you slow. In a crosswind after-landing roll this culminates in aileron held fully toward the wind by the time the airplane is coming to a stop (AFH ch 14).