Directional Control "If you want it to happen, you must make it happen. If you let it happen, you won't like what happened" - Dale Adams

Ground Loop - violent uncontrollable turn during ground operations Swing – an undesirable but controllable turn during ground operation Terminology … Ground Loops Be sure to watch the “Directional Control” Video in the DOWNLOADS section.

The PILOT is the cause of the majority of ground loops ! Ground Loops

1. Aerodynamic Factors Torque Asymmetric Thrust Slipstream Effect Gyroscopic Precession Inertia 2. Environmental Factors Wet Grass Rough or Soft Terrain Crosswind Tailwind Wind Gusts 3. Pilot Induced Factors Abrupt Control / Power Movements Taxiing Too Fast for Conditions Pilot Inattention Pilot Bravado 4. Equipment Failure Locked Brake Under-inflated or Flat Main Tire Loss of Brake Pressure Contributing Causes

Aerodynamic Factors

Use Aileron to assist in all scenarios

Pilot Bravado

1. All aerodynamic forces combine to produce a strong tendency for the aircraft to swing (yaw) to the left. Swings on Take-off … 2. Gyroscopic precession – Most obvious when the tail is raised during take-off. 3. Torque & Slipstream – Reduced as aircraft accelerates due to the off-set vertical stabilizer. 4. Asymmetric Thrust – Reduced to “zero” as the aircraft attains a level attitude just prior to lift-off.

Torque, Asymmetric Thrust, Gyroscopic Precession & Slipstream Effect are minimized during landing due to reduced power settings. Swings on Landing … 1. Touching down while crabbing into wind 2. Touching down while aircraft is drifting sideways 3. Allowing upwind wing to rise ( Combined with weathercock ) 4. Failing to control a wheel landing 5. Incorrect recovery action for drift after a bounce ( same effect as landing with drift ) Other Causes of a Swing on Landing …

Aircraft control surfaces become less effective as landing speed decreases, requiring larger control inputs. As control surface effectiveness continues to decrease, tail wheel steering, brakes, and possibly power must be used to stop a swing. Stick must be kept full back to ensure the aircraft’s tail wheel can be used for maximum steering and to prevent nose-over during heavy braking. Reminders

Preventing the Ground Loop The easiest and simplest way to prevent a ground loop is never to allow a swing to develop. 1. Look well ahead to detect yaw as soon as it begins. 2. The aircraft must be kept straight by immediate and corrective action. 3. Every swing must be responded to before there is an inch of displacement between the longitudinal axis and the inertial force vector.

Power - One of the least considered, but one of the most effective controls. 1. As power is increased, hold full rudder & full back-stick. 2. As swing shows signs of stopping, reduce power 3. Leave it on only as long as necessary to correct the swing. 4. If there is room to stop, do so straight ahead. Using Power to Counter a Swing … “There is a temptation to leave full power on and go-around. Many have tried it, usually to their grief!” Many have tried it, usually to their grief!”

1. The tail dragger pilot must use all available controls to keep the aircraft straight after landing, and during deceleration and taxi. Ground Loop Summary … 2. If a swing starts, respond immediately with rudder & aileron. 3. If a swing continues, use brakes immediately. 4. If a swing still continues, use power immediately. 5. Reduce power as soon as swing is eliminated. 6. Application of controls, brakes & power must occur very rapidly and will probably occur simultaneously as the severity of the swing progresses. Remember… Look well ahead to maintain directional control as this will allow you to detect yaw, crab, or drift much easier.

Ground loops don’t always happen on the runway. Taxiing too fast on the ramp or a taxiway can lead to a ground loop too. Often Forgotten Fact

A ground loop can happen to any pilot, regardless of experience BE CAREFUL

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