task 4 primary and secondary flight controls

Sebastian Kubiak DT011/1 AVTE 1103 Date: 06:11:2015

Task Number : 4Sebastian Kubiak

C15452032 Aron, Richard and Seamus.

1. Title of the Task/Demonstration:

Task 4 : Primary, Secondary and Auxiliary Flight Controls.

2. Short Abstract:

Me and my group were encouraged to operate all the primary, secondary and auxiliary flight controls with an assistance of our lecturer. We had to brainstorm in group how the pilot controls the aircraft and uses forces of aerodynamics to control each aircraft at the ATC – The Fouga 215, Learjet 25B and the Robinson R22 Helicopter. We had to connect the aircraft to a ground power unit and switch on the battery button in the cockpit in order to provide the electricity to the aircraft to control the secondary flight controls.

3. Aim or Objective of the Task/Demonstration:

The primary learning outcome of Task 4 is to identify different types of primary and secondary flight controls. We will discuss in group how pilot uses – Pitch, Roll and Yaw and also secondary flight controls such as – Flaps, Airbrakes and Spoilers to control the aircraft and which controls is the pilot using.The secondary learning outcome is that we will be able to identify the auxiliary controls devices such as Tabs and stall strips. We will learn how secondary flight controls are operated in the aircraft and also we will learn what is the purpose of Flaps, Airbrakes and Spoilers and how it aids the pilot with the control of the aircraft. Finally we will learn what components are used to control these flight controls.

4. Theory, Laws & Principles of the Task/Demonstration:

Initially, we figured how do the primary flight controls affect the aircraft and what makes these controls so efficient during the flight. After doing research we considered the Mean Camber Line theory. This is vital to how the aircraft flies. Mean Camber Line theory states that when a surface is moving and the part which is controlled moves, it changes the Mean Camber line it causes lift on the surface. For instance


when the pilot rolls the aircraft to the left side, the left aileron moves up causing a little bit of drag and pushes the wing downwards and the right aileron moves down causing lift and rolls the aircraft to the left side. The same theory applies to the Elevator which makes the aircraft pitch, Rudder which makes the aircraft yaw, Flaps which cause drag on aircraft and up to 90% extra lift. Trim Tabs work in similar way, however, trim tabs are being locked in a certain degree which relieves the pilot from holding on strong to the yoke or joystick by causing small amount of lift which could be required to keep the aircraft in a level position.

Diagram describing Mean Camber Line Theory

Flaps are causing additional lift which may be required during take-off or landing. During take-off flaps do not need to be extended fully, only a little amount of lift is required as the aircraft is gaining velocity and the extra lift which is caused by flaps extended to about 5 degrees is enough during take-off.During landing, however, aircraft needs to be traveling at a lower speed so it will also need extra lift, flaps enable the aircraft to travel at a lower speed without losing altitude which is vital during the landings. Aircraft needs to stop before the runway ends so flaps cause the drag which is needed to slow down the aircraft and also give extra lift so it can descend slowly until it touches the runway. Usually flaps are being extended gradually during the landing and eventually reach the maximum extension level being closer to the runway. As well as it slows the aircraft down, it puts less pressure on the breaks preventing the quicker wearing. There are many types of flaps for the aircraft, the most common ones used on a commercial aircraft are the Fowler Flaps which increase the wing surface area also giving the aircraft more lift.


Spoilers and Airbrakes mainly have the same purpose, both are used to slow down the aircraft. Spoilers are deployed from the wings and spoil the smooth airflow, reducing the lift and increasing drag. On jet turbine aircraft, spoilers are mainly used to control the adverse yaw, which for instance when aircraft turns right, the spoiler on the right wing is slightly raised creating little bit of drag which is an advantage while controlling the adverse yaw. After landing the spoilers destroy the lift and while on the ground by destroying lift they transfer weight to the wheels and improve the breaking efficiency. Airbrakes are mainly used in acrobatic or fighter aircraft, unlike the spoilers, the airbrakes are mainly used for slowing down the aircraft while not destroying the lift. Airbrakes are stronger than spoilers and will take more load than spoilers giving the pilot quicker response than spoilers and can withstand the variable g-forces.

Adjustable stabiliser is similar to elevator tabs, however, adjustable stabilisers do not require the elevator tabs as the stabiliser can be adjusted to a required degree giving the aircraft similar effect as the trim tabs.

5. Description and Diagram of Equipment or Apparatus:

There is thee different aircraft at the ATC, Fouga 215, Learjet 25B and the Robinson R22 helicopter.

Fouga 215 is a military aircraft, it uses two jet engines located under the wings connected with the fuselage. It has a V-tail because of the location of the engines.

The Robinson R22 is a small helicopter powered by a piston engine.

Learjet 25B is a private jet, this aircraft uses two jet engines located on the back of the fuselage. The horizontal stabiliser is located on the top of the vertical stabiliser to prevent getting damaged by the engines.

Ground Power unit and hydraulic unit was used.


6. Methods and Procedures:

Initially, the primary flight controls of all three aircraft at the ATC were tested. It was achieved by entering the cockpit of these airplanes and locating the primary flight controls.The Robinson R22 helicopter was tested first, by moving the cyclic to all directions. Anti-torque pedals in this aircraft were examined by putting pressure on each pedal. Finally collective lever was used by pulling or pushing on the lever and observing what difference this had on the blades of the aircraft. All the observed data was recorded in a Lab Diary as a final stage.The Fouga 215 was the second aircraft that was tested. Its primary flight controls are controlled using a joystick and rudder pedals. Same method was applied to this aircraft. Which is moving the joystick to all directions and pressing the rudder pedals.Learjet 25B was the final aircraft examined which included controlling the yoke of this aircraft by moving it in all different directions. Rudder pedals were tested in the same method as the Fouga 215 and the observations were recorded in a Lab diary.

The secondary and auxiliary flight controls required a power source. The Learjet 25B was connected to the ground power unit (GPU) and the electric power was bought to the aircraft. The aircraft was connected to the hydraulic power unit so the aircraft will have hydraulic pressure in order to operate all secondary flight controls. The battery switch in the cockpit was switched on which enabled the secondary and auxiliary flight controls to be operated. For Fouga 215, there was no need to connect the ground power unit so it was just connected to hydraulic unit.

The secondary and auxiliary flight controls in Learjet 25B were examined at the initial stage. Flaps were enabled at the beginning using the flaps lever which was located on the right hand side of the thrust levers. By pulling and adjusting flaps to full extension gradually which is 30 degrees. The spoilers were deployed using a little knob located near the thrust levers. The horizontal adjustable stabiliser was controlled using the scroll wheel on the yoke of the Learjet. All the observations were recorded in the Lab Diary.

The Fouga 215 was also checked for its secondary flight controls. The aircraft was connected to the hydraulic power unit so the aircraft will gain the ability to control the secondary flight controls. Flaps on the Fouga were extended using a little knob located near the thrust lever by using the finger to adjust the angle of the flaps. There is no intervals for lowering the flaps in the Fouga so flaps were extended fully and then they were moved up to its original position. Extension of airbrakes was also necessary, it was achieved by using the button on the thrust lever within the cockpit. However, there was a problem with lowering the airbrakes so it had to be done manually. All observed data was recorded in the Lab Diary.

7. Actions/Recorded Experimental Data:

Our class was divided into three groups of four people and we got 40 minutes to spend on each aircraft within the ATC. Our first step was to control the primary flight controls in the Fouga 215, Learjet 25B and the Robinson R22 helicopter.


At the beginning, our lecturer presented how the aircraft uses cables, rods and pulleys to control ailerons, elevators and rudder. Hydraulic and pneumatic systems were presented to us to give us a better understanding of how they work

The first aircraft we had to experiment with was the Robinson R22. Initially we located the primary flight controls within the cockpit of the helicopter. After locating the cyclic, collective lever and the anti-torque pedals we had to determine what effect does each of these controls have on this helicopter. Primarily we controlled the cyclic by moving it to all directions and observing what happens to the blades of the helicopter.

Each person of our group got a chance to use the cyclic stick and while the person was controlling the cyclic the rest of the group concentrated on the outside of the aircraft, noting what happens to the helicopter. The same method was repeated with the anti-torque pedals and the collective lever.

Finally all of us gathered together and brain stormed what happens to the helicopter when the primary flight controls are used. Second aircraft examined was the Fouga 215. Each member of our group entered the cockpit and located all of the primary flight controls. We learned that the primary flight controls on this aircraft are controlled by joystick and rudder pedals.


While Seamus was inside the cockpit, and used these controls, me and my group members were standing outside the aircraft and observing what happens when he uses these controls, each one of us got the chance to use these controls. We recorded the observations and brainstormed how does each of these controls affect the aircraft in flight.

The final aircraft to be examined was the Learjet 25B. This aircraft had a yoke to control the pitch and roll while in flight, rudder pedals controlled the rudder on the back of the aircraft which was used for yaw turn. Same procedure as mentioned above was applied and all of us had the chance to be behind the flight controls of this aircraft and each one of us got the chance to look what is happening to the aircraft when these controls are operated. As mentioned above, we brainstormed how can the flight controls control the aircraft in flight.

The second task we had to do was control the aircraft secondary and auxiliary flight controls. For this task we had to connect the electric power and hydraulic power to the Learjet 25B. I connected the ground power unit to the power supply located on the wall of the hangar. Before we connected the power supply to the aircraft, the aircraft had to be inspected inside the cockpit to make sure that the battery switch and all the electric devices inside the aircraft are disconnected for safety reasons. After everything was checked by Richard I connected the Ground Power unit to the aircraft followed by the hydraulic power. When that was successful, Aaron went inside the cockpit and activated the battery switch which bought the electric power to the aircraft.


Out next step was to actually control the flaps of the aircraft. That was done by Seamus and achieved by locating the flap lever which was on the right hand side of the thrust levers and gradually setting the flaps to full extension and watching the meter indicating the flap extension.

Rest of the group was outside the aircraft and noted observed changes. This step was repeated with all of our group members so everyone had a chance to operate the flaps on this aircraft. This was followed by deploying the spoilers on the aircraft. With the aid of our lecturer we located the spoiler knob which was located just in front of the flap lever. Same method applied, one of our group members was sitting inside the aircraft and deployed the spoilers and reversed the action multiple times while three of us were outside noting the changes observed, this step was repeated with all of our group members.

For the final step we operated the adjustable horizontal stabilizer in the Learjet using the knob located on the yoke. Same method applies.

Next, we operated the secondary flight controls on the Fouga 215. Fouga didn’t require the electrical power supply to control the secondary flight controls, only hydraulic pressure was needed in order to operate the flaps and the airbrakes. That was connected by Aaron and similarly to Learjet, one of us was sitting in the cockpit extending the flaps with a knob located near the thrust lever while others were observing the changes to the aircraft. The airbrakes were controlled using a switch on the thrust lever. Similarly it was tested by one person while others were nothing the changes and after a time we switched around so everyone will get the chance of using these controls.


Our last step was to brainstorm what the controls do to the aircraft and how can it be used in flight. 8. Results and Discussion:

Primary Flight controls of all aircraft are the main ways of controlling the aircraft, in the Learjet and Fouga primary flight controls include ailerons, elevator and rudder. In Robinson R22 it includes mainly the blades.

From the observations made on the Learjet 25B, when the yoke is tilted forward it causes the elevator to tilt downwards causing the aircraft do descend, opposite effect happens when the yoke is pulled backwards this is called pitch. When the yoke is rotated to the right the aircraft banks right and when the yoke is rotated left the aircraft banks to the left, it is caused by the ailerons ,for instance, when the yoke is rotated right, the left aileron moves downwards and the right aileron moves upwards and vice versa when yoke is rotated to the left this is called roll. I noticed when the left rudder pedal is pressed the rudder moves to the left causing the back of the aircraft to drift right and the aircraft to turn left vice versa when right rudder pedal is pressed, this movement is called yaw.

Fouga 215 from my observations, it was clear that the ailerons work on the same way as the Learjet, which means that if you tilt the joystick to the left the right aileron moves downwards and the left moves upwards causing aircraft to roll right and vice versa. However, there are no elevators on this aircraft because it has a V-tail the rudder and the elevator is in the same place. When you pull on the joystick the elevator moves us causing the aircrafts nose to move up and vice versa. When pressing on the left rudder pedal the two rudders on the V-tail move right causing the back of the aircraft to drift left and the front of the aircraft to turn right.

The Robinson R22 uses mainly the blades to control its heading and the rate of ascending. While using the cyclic and tilting it forward I noticed that the blades which are placed on the bearings tilt forward as well causing the helicopter to increase its velocity and opposite happens when the cyclic is pulled back it causes the helicopter to tilt backwards. When cyclic is tilted right the blades also tilt left causing the helicopter to bank left and opposite when you tilt the cyclic right.


The collective lever changed the angle of blades, for instance, when you pull the collective lever the angle of the blades increase, the angle of blades is called the angle of attack and it determines how quickly does the helicopter increase its altitude, if higher the angle of attack the quicker will the helicopter gain its altitude. The anti-torque pedals controlled the tail rotor of the helicopter. Using the anti-torque pedals caused the angle of blades located on the tail rotor change its angle as well, for instance when pressing the left pedal, tail rotor blades increase its angle of attack and both twist right which causes the aircraft to yaw left and vice versa.

Secondary Flight Controls Help the pilot to control the aircraft.The observations we made as a group helped us to understand how do these secondary flight controls aid the aircraft. In the Learjet 25B, the flaps when extended, cause drag and more lift, this helps the aircraft fly at lower speeds without losing altitude. Flaps and spoilers on the Learjet are operated with an aid of hydraulic system. When spoilers are used, it slows down the aircraft and destroy lift causing the aircraft to slow down. Our last observation made included the adjustable horizontal stabilizer. Horizontal stabilizer aids the pilot while inflight if the correct degree is set. When the knob on the yoke is moved, it changes the degree of the stabilizer which then causes a little bit of lift or destroys lift which could be necessary for pilot to relieve pressure from the primary flight controls. On Fouga 215, flaps have the same purpose as on the Learjet 25B and are controlled by the same hydraulic system as on Learjet 25B. The Fouga uses rods to lower its flaps. Airbrakes on the Fouga 215 deploy from the center of the wings, this causes drag by spoiling smooth air in flight. It slows the aircraft down faster than spoilers.

9. Conclusion(s) & Comments:

This assignment examined the primary, secondary and auxiliary flight controls within the aircraft. It can be concluded that these controls are vital on the aircraft. We learned that the different flight controls within the aircraft also matter. In helicopter the cyclic stick is very useful because as it makes it easy for pilot of this helicopter to move forward by simply pushing on the cyclic stick. Within Fouga there is a joystick, this is useful as joysticks do not take much space to operate and can be simply controlled. Learjet uses a yoke as it makes it easier for a pilot of this aircraft to control it at higher speeds. The secondary flight controls within the Fouga and Learjet are working on the similar basis, however the Fouga doesn’t require an electric source of power and the Learjet does. While the aircraft is turned on and the engines are running this power is provided by the generators inside the engines on both aircraft, while they are on standby on the ground the aircraft are connected to a ground power unit.

Our final statement proved our theory stated above. From this we can see that theory is vital on the aircraft as it provides basis to the flight controls.