Aircraft Roll Control

After mastering power and pitch control adequately, the next training element is rolling by itself. Read on as we discuss effective aircraft roll control.

Introduction

Effective aircraft roll control is achieved by co-ordinating your turns, being aware of the balance ball and practicing the rolling maneuver. It’s always best to avoid motion sickness and master roll control for optimum safety for everyone on board.

Contents hide

1 Introduction

2 Rolling the aircraft

3 Balance ball

4 Practicing the rolling maneuver

5 Motion sickness

6 Adverse aileron yaw

7 Conclusion

Rolling the aircraft

Rather than learning how to roll into a banked attitude and maintaining bank to turn the aircraft, a useful way is to first learn how to input coordinated roll in both left and right directions, smoothly using rudder to prevent adverse aileron yaw. You will revisit level, climbing and descending and steep turns later, so for now this article will just focus on the method of achieving roll control alone.

The best way to visualize the objective is to imagine the aircraft as a chook on a rotisserie with a rod passing through the propeller spinner to the horizon in front, and through the tail to the horizon behind.

The idea is to achieve a smooth rolling motion to the left, then back to the right repeatedly while preventing the rod from moving – and only allowing the aircraft to be rotating on this roll axis – the extended longitudinal axis. By doing this, and as the aircraft rotates, you’ll learn how to roll correctly using coordinated rudder, keeping the aircraft and the airplane’s wings balanced through external observation only. You can read more about Aircraft Roll Motion on the NASA website HERE¹.

aircraft roll control — As the aircraft rotates, you’ll learn how to roll correctly using coordinated rudder, keeping the aircraft and the airplane’s wings balanced through external observation only.

Balance ball

Reference to the balance ball is not strictly necessary at all if this method is learned, as well as the preceding method for achieving balance in straight flight, because you’ll be able visually perceive yaw directly while rolling and during a turn, thereby enabling the use of rudder as necessary to prevent adverse yaw.

That’s not to say the balance ball isn’t a great instrument to scan as part of your ALAP cycle – you certainly should, and apply rudder as needed to centre the ball (step on the ball). Aviation Safety Magazine has further info on Flying the Ball in this article HERE.²

However, your primary reference should be to visual features out of the front of the cockpit – for example a mountain range, dam, large shed (or even a particular cloud!)

Practicing the rolling maneuver

Once you are established within the training area and have completed your HASELL checks³ (and after a decent lookout), begin practicing rolling.

To begin, try rolling just 15 degrees either side of level and back to level again, gradually increasing the bank angle as proficiency is gained.

Fix your gaze straight out of the front of the aircraft and Notice any tendency for the aircraft to yaw in the opposite direction to the turn – keep the sight picture out of the front from yawing by applying coordinated rudder in the direction of the roll. Left stick = left rudder.

The adverse yaw will be more pronounced with larger roll control inputs, at slower speeds, and in aircraft with longer wingspans and larger ailerons. Practice with your instructor at a variety of roll input rates and airspeeds.

Once you have an idea of this, try rolling the aircraft using a coordinated roll into a banked state, and then applying opposite rudder to prevent the aircraft from turning – you will feel a strong side-slip as the aircraft rudder ‘fights’ the banked lift vector to prevent the turn.

Unless you have a very responsive aerobatic aircraft, the most bank angle you’ll be able to roll either side without turning is around 45 degrees.

Once banked that far, roll response rate will determine whether it can be rolled back the other way before the nose starts to drop. Take it as far as you can while maintaining heading and pitch attitude, and you’ll learn how to use rudder instinctively.

roll control — The best way to visualize the objective is to imagine the aircraft as a chook on a rotisserie with a rod passing through the propeller spinner to the horizon in front, and through the tail to the horizon behind.

Remember, this a skill that will pay off in the long term for all concerned. You will have developed the necessary foundations to enable future skill development with greater ease and competence, you’ll know how to fly in such a way that drag is minimized, and your future passengers will have their flight safety and comfort assured.

Be aware, this ‘crossed up’ condition is a pro-spin input, and large angles of bank in uncoordinated flight (balance ball not centred) at low airspeeds, with abrupt control inputs can cause one wing to exceed the critical angle of attack and stall, causing you to enter a spin (thankfully, your instructor is trained to recover from spins and teach you the PARE and begs-mueller spin recovery techniques as appropriate).

Motion sickness

After you’ve had to clean up passengers’ vomit a few times in the flight deck and nearly thrown up yourself at the sight and smell, you’d clearly see why this is a very important topic to learn and put into practice. A passenger sitting at the rear of an aircraft will be most affected by poor use of rudder, especially in turbulence.

If the aircraft is constantly rolled in a left or right direction without co-ordinating rudder properly, the nose and tail yaws around the vertical axis, and the further a person is seated from that axis, the greater the movement is accentuated. Since the pilot is usually seated close to the yaw axis, they’re less likely to perceive out of balance flight or suffer from motion sickness. You can read more about Motion Sickness HERE⁴.

“Although we don’t know a great deal about “aviation nausea,” there have been some studies that suggest that motion sickness occurs in a relatively high percentage of aviation participants, both passengers and pilots. Some surveys indicate that more than 25% of airline pilots have experienced motion sickness. The symptoms most likely occur because of conflict caused by the stimulation of the vestibular apparatus in the inner ear (the semicircular canals) where the balance mechanisms reside and the resulting visual cues that send information to the brain. “
aopa.org/go-fly/medical-resources/health-conditions/ear-nose-throat-and-equilibrium/motion-sickness⁴

aircraft roll, commercial aircraft — If the aircraft is constantly rolled in a left or right direction without co-ordinating rudder properly, the nose and tail yaws around the vertical axis, and the further a person is seated from that axis, the greater the movement is accentuated.

Understanding the cause of motion sickness should assist at this stage of flight training too. Motion sickness is caused by confusion between the messages received from our balance organs and what we’re seeing.

Passengers get nauseous when their vision isn’t focused far enough away to discern subtle movements relative to the ground that correspond to what the balance organs are perceiving, usually when they’re looking inside too much, thereby not perceiving visual indications of movement.

If a pilot experiences motion sickness, which is indicated by a glazed look on their face and lack of head movement, the best cure is to fly straight and level while focusing on a distant reference point on the horizon. Remember to breathe as well, and direct fresh air onto your face to cool yourself down if you break into a sweat.

In summary, getting your eyes and mind focused externally, rather than internally, provides a stable reference datum for the balance organs to integrate what they’re sensing.

Adverse aileron yaw

The reason the aircraft yaws is due to adverse aileron yaw⁵ – if you roll left, the left aileron goes down (reducing lift on that outer section of the left wing) and the right aileron goes up (increasing lift on that outer section of wing). The lift differential causes the aircraft to roll left, however, due to the additional drag (induced and control drag) on the up going aileron, the aircraft tends to yaw in the opposite direction to the roll.

“Adverse yaw is the tendency of an airplane to yaw in the opposite direction of the turn. For example, as you roll to the right, your airplane may initially yaw to the left.”
boldmethod.com/learn-to-fly/aerodynamics/how-adverse-yaw-affects-your-plane-during-a-roll-left-and-right⁵

This is why we need to smoothly coordinate our roll inputs on the control column with rudder inputs using our rudder pedals – in the same direction. If you want to roll left, you introduce left rudder. If you want to roll on bank to the right, you introduce right rudder.

Adverse aileron yaw is more pronounced at slower speeds, when the airplane flies at higher angles of attack – such as take off and landing, or during stalling manoeuvres.

Conclusion

Learning how to make coordinated roll and rudder inputs to the aircraft is a core flying skill, and by learning from first principles visually you set yourself up with the correct primacy principle. Cross checking you are coordinated at any stage of flight (especially turns) using the balance ball is a part of every pilots scan, but you must learn to feel side-slip and how to counter adverse aileron yaw from first principles both visually and using your proprioceptive system (the seat of your pants!).

By mastering roll control and being able to coordinate your turns, you improve flight safety and significantly improve the comfort of yourself, other pilots and passengers, a hallmark of good airmanship.