The aircraft flight control system is made up of the primary aircraft flight control system and the secondary system. In the primary system, there are three components which includes the ailerons, the elevator, and the rudder. The second system consists of the wing flaps, spoilers, trim systems, and leading edge devices. These control systems are the method in which pilots can steer, and increase or decrease height. For a high level basic look at these systems, it helps to analyze the role and function of the three primary flight control surfaces.

Ailerons

The ailerons are flaps located on the outer ear edge of each wing. When the pilot moves the control stick to the right, the flap on the right wing turns up while the flap on the left wing turns down. This creates a difference in air pressure on each wing, with the right wing decreasing pressure below the wing, and thus decreasing lift. The opposite happens on the left wing with the wing gaining lift because the air pressure below the wing was increased. The overall effect: the aircraft is able to steer to the right.

Elevator

Known also as the stabilizer, the elevator is a hinge located on the horizontal tail fin. The elevator is designed to control the pitch of the aircraft, meaning it controls the up and down movement of the nose of the aircraft. They operate in the same manner that the ailerons operate, in that when the elevator is pointed up, the plane goes up. By moving the elevator up, there is less lift on the tail and vice versa

Rudder

The rudder is found on the vertical tail fin and is used with the aileron to turn the aircraft. The rudder swivels left or right, and in turn, causes the plane tail to turn in either direction. Its role is to counter the adverse yaw rotation of the plane, which is the movement on the yaw axis that moves the nose of the aircraft side to side.

If you need aileron parts, rudder assembly parts, elevator assembly parts, or other parts of the primary flight control systems, reach out to the team at Aviation Sourcing Solutions, the leading online distributor of hard to find aviation parts and MRO services.

At Aviation Sourcing Solutions, owned and operated by ASAP Semiconductor, we can help you find all the unique parts for the aerospace, civil aviation, and defense industries. For a quick and competitive quote, email us at sales@aviationsourcingsolutions.com or call us at + 1-714-705-4780.


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Even on small aircraft, a way to precisely locate structural components is essential for maintenance and repairs. Various numbering systems are used to locate specific wing frames, fuselage bulkheads, or other structural components on an aircraft, with most manufacturers using a system of station marking. For example, a nose may be designated “zero station,” and all other stations are located at measured distances in inches behind the zero station. When a blueprint reads fuselage frame 137, that station can be located 137 inches behind the nose of the aircraft.

To locate structures to the left or right of the center line of an aircraft, a similar method is employed. Most manufacturers consider the center line of the aircraft to be a zero station from which measurements can be taken to the left or right to locate an airframe member. This is most often used for the horizontal stabilizers and wings.

When trying to locate a structure member, always double-check a manufacturer’s numbering system, as they can differ from company to company. However, most use designations similar to one another.

  • Fuselage stations (Fus. Sta. or FS) are numbered in inches from a reference or zero point known as the reference datum. The reference datum is an imaginary vertical plane at or near the nose of the aircraft from which the fore and aft distances are measured. The distance to a given point is measured in inches parallel to a center line extending through the aircraft from the nose through the center of the tail cone. Some manufacturers also call the fuselage station the body station, or BS.
  • Buttock line or butt line is a vertical reference plane down the center of the aircraft from which measurements left or right can be made.
  • Waterline (WL) is the measurement of height in inches perpendicular from a horizontal plane usually located at the ground, cabin floor, or some other easily referenced location.
  • Aileron station (AS) is measured outboard from, and parallel to, the inboard edge of the aileron, perpendicular to the rear beam of the wing.
  • Flap station (KS) is measured perpendicular to the rear beam of the wing parallel to, and outboard from the inboard edge of the wing.
  • The nacelle station (NC or Nac. Sta.) is measured either forward or behind the front spar of the wing and perpendicular to a designated water line.

In addition to these, larger aircraft may also have horizontal stabilizer stations (HSS), vertical stabilizer stations (VSS), and powerplant stations (PSS). In every case, the manufacturer’s terminology should be consulted.

At Aviation Sourcing Solutions, owned and operated by ASAP Semiconductor, we can help you find all the aircraft fuselage parts for the aerospace, civil aviation, and defense industries. For a quick and competitive quote, email us at sales@aviationsourcingsolutions.com or call us at 1-714-705-4780.



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Smaller aircraft have relatively low flight control loads, and the pilot can operate the flight controls on hand without issue. However, as aircraft started to fly faster and get larger, hydraulic power boost systems were implemented to help maintain control. Power boost systems assist the pilot in overcoming high control forces, but the pilot can still actuate the flight controls by cable or push rod. In recent years, electric fly-by-wire systems unassisted by hydraulics have become more prevalent, such as on the F-16 Fighting Falcon and 787 Dreamliner, but many other models still rely on hydraulic systems.

In most aircraft, hydraulic power packs serve as the power boost systems. A hydraulic power pack is a small unit that consists of an electric pump, filters, a reservoir, and valves. The advantage of a power pack is that there is no need for a centralized hydraulic power supply system and long stretches of hydraulic lines, which reduces overall weight. Power packs can be driven by either the engine gear box or electric motor. By integrating all essential valves, filters, sensors, and transducers, packs reduce system weight, eliminate the opportunity for external leakage, and simplify troubleshooting. These power pack systems will have an integrated actuator which is used to control stabilizer trim, landing gear, or flight control surfaces directly.

Power pack systems follow the same principles and use the same types of parts as all hydraulic systems, starting with the reservoir. The reservoir is the tank in which an adequate supply of fluid for the system is stored. Fluid flows from the reservoir to the pump, gets forced through the system, and eventually returned to the reservoir. The reservoir supplies the operating needs of the system, and replenishes fluid lost to leakage. The reservoir also serves as an overflow basin for excess fluid forced out of the system by thermal expansion, the accumulators, and by piston and rod replacement.

All aircraft hydraulic systems have one or more power-driven pumps and may have a hand pump as an additional unit for emergency circumstances. Most power-driven hydraulic pumps are of variable delivery, compensator-controlled type.

Valves control the speed and/or fluid flow in the hydraulic system. They provide for the operation of various components when desired, and the speed at which the components operate at.

Filters are installed in the piping of hydraulic systems to, as their name implies, filter hydraulic fluid. This includes preventing air bubbles forming, and to straining out foreign contaminants.

At Aviation Sourcing Solutions, owned and operated by ASAP Semiconductor, we can help you find all the hydraulic systems and parts for the aerospace, civil aviation, and defense industries. For a quick and competitive quote, email us at sales@aviationsourcingsolutions.com or call us at 1-714-705-4780.



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A slip ring is an electrical connector component that is designed to carry a current from a wire into a rotating device. It can be used in any electromechanical system that requires rotation while it transmits power. Slip rings can simplify system operations, eliminate the need for freestanding wires, and improve overall mechanical performance. 

The composition of slip ring hardware consists of a graphite or metal contact brush which moves on the outside diameter of a rotating ring. As the ring turns, the electric current is conducted through the brush to the metal ring, establishing a connection. Slip rings typically operate with multiple rings that provide an even distribution and flow of electrical current to multiple portions of the device. The wires from the immobilized structure loop around the compartment which houses the electricity conducting rings. Power can be supplied to the slip ring by connecting wires to the brush wire, through the brush block. The electricity transfers from the brush wires to the metal rings, then makes its way to the outside slip ring, and ultimately ends up at the device. 

Slip rings are used for power, electrical generators, alternators, ethernet signal transmission, proximity switches, and many other functions. They are available in a wide array of configurations, types, and materials to fit most applications. For low current signal circuits, gold on gold slip rings are recommended. In cases of higher current power circuits, silver on silver slip rings work best. Slip rings are often integrated into rotary unions and send power/data to and from rotating machinery with a single device. 

Slip rings can be organized into three classifications: shaft type, disk type, and differential slip. The ring surface of shaft type slip rings is distributed along the axial direction. These rings are isolated by insulating sheets and have high reliability/durability; they are also low cost and easy to maintain. Disk type slip rings utilize a series of concentric rings to load electric currents. The brushes are distributed on top of concentric rings and act as a stator. Differential slip rings have a complex structure and high manufacturing costs as they are composed of three parts: differential mechanism, ring core, and auxiliary components. They are mainly used in radar systems and military applications. Slip ring technology is impressively diverse and can be utilized in many industries.  

At Aviation Sourcing Solutions, owned and operated by ASAP Semiconductor, we can help you find all the slip ring parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@aviationsourcingsolutions.com or call us at +1-714-705-4780.


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Engine ignition leads are used to power spark plugs for prominent commercial assemblies— the Rolls Royce Trent 1000 utilized by Boeing B787’s, Rolls-Royce Trent 900 engine integrated on the Airbus A380, and Pratt & Whitney PW2000 engines all incorporate some type of ignition leads. Spark plugs allow combustion within the ignition system but transferring current across a spark plug gap wouldn’t be possible without ignition leads.

In a piston engine assembly, a spark plug is attached to the magneto through means of ignition leads. The actuator component sends positive voltage across one lead, and negative voltage down the next lead. Current from the ignition leads form a conductive path between the ground and center electrodes of a spark plug. At this time, the plug is able to fire. 

The more capacitance a lead has, the more current it can generate across the spark plugs’ gap between its ground electrodes and its core. The distance between the core and electrodes is engineered to build up to a specified voltage before firing and discharge.

In a gas turbine engine, standard ignition leads, or high-tension ignition leads are utilized to provide voltage to ignitor plugs within a capacitor-type system. The functioning of leads in this capacity is similar in concept, but on a bigger scale. An igniter plug must handle higher energy current than a spark plug. Because an igniter plug also operates in an environment that has lower operating pressure but a higher voltage emission upon firing, it features a wider electrode gap than a spark plug.

For both piston engine and gas turbine engine applications, dual ignition systems are required by the Federal Aviation Association. This ensures that if the ignition system has a problem, the other components can act as a continuous ignition system until the issue can be resolved.

At Aviation Sourcing Solutions, owned and operated by ASAP Semiconductor, we can help you find ignition leads, spark plugs, and more. For a quick and competitive quote, email us at sales@aviationsourcingsolutions.com or call us at +1-714-705-4780.


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Most car owners know of spark plugs because they’re a common engine component that often needs to be replaced and are integral for an engine to work. Without them, the engine will not start. The electrical energy from the plugs is used to create a spark, which ignites the fuel-air mixture in the combustion chamber. 

Spark plugs are connected to high voltage— generated by an ignition coil or magneto. Current flows from the coil and a voltage develops between the central and side electrodes. But, fuel and air in the gap acts as an insulator and prevent an immediate fire. When the voltage exceeds the dielectric strength of the gases, the gases ionize— the gas then becomes a conductor, allowing the current to flow. The increase in the temperature of the spark channel causes the ionized gas to expand rapidly, which generates a small explosion.

The thermal performance of spark plugs indicates their heat range, or their ability to dissipate heat. On the firing end of a spark plug, the temperature must be high enough to prevent fouling but low enough to prevent pre-ignition. Cold spark plugs have a short heat flow path, which results in a quick rate of heat transfer; on the other hand, hot spark plugs have a longer heat transfer path, which results in a slower rate of heat transfer. It’s important to choose spark plugs that create optimal thermal performance. If the spark plug is too cold, it can cause carbon fouling and if it’s too hot, it can cause overheating.       

Although they are common components in an engine, they are not simple, and are made to be very precise. Their construction includes ribs, an insulator, the hex, shell, plating, gasket, threads, ground electrode, center electrode, spark park electrode gap, and an insulator nose.

At Aviation Sourcing Solutions, owned and operated by ASAP Semiconductor, we can help you find all the spark plugs and insulator parts you need, new or obsolete. For a quick and competitive quote, email us at sales@aviationsourcingsolutions.com or call us at 1-714-705-4780.


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Automatic direction systems serve a fairly simple purpose— locate, and point, in the direction of an NDB signal. Non-directional beacons (NDBs) are used for anything from Morse code broadcasts to voice interfaced communication to inform pilots about weather conditions. They communicate important information directly to the automatic direction finder (ADF). Simple enough, right? Let’s take a look at how an ADF accomplishes this functionality using two types of antennas: loop and sensing.

An NDB emits two electromagnetic field components at a time. One, is referred to as the E field, or electrical field. The other, is known as the H field, or magnetic field. Both fields run perpendicular to one another. The H field runs on the x-axis or plane, and the E field runs on the y axis or in a polarized direction.

A loop antenna is a structure that utilizes two perpendicular windings on a closed loop, and a ferrite core. Due to the closed loop functionality, H voltage is split and becomes null at two locations on the loop, these “null points” allow the ADF to assume that one point is facing in the direction of an NDB.

A sensing antenna receives the E field voltage. By measuring this voltage, and that of the two windings on the loop antenna, the ADF is able to calculate the location of the NDB signal. Both structures are typically located on the underside of an airframe.

ADFs are not as common in newer aircraft. More efficient models using GPS technology and VOR/ILS components have replaced many of the ADF units that were once utilized in locating NDB stations and signals. These advanced versions are less vulnerable to icing and water damage. In addition, technological advancement has enabled the antennas to be combined into one unit, reducing drag.

Pilots that are well acquainted with the functionality of an ADF might still prefer this mechanism. Interestingly enough, ADF components were once referred to as the “poor man’s lightning detector” as they operate on the same low frequency of lightning discharge and will sometimes detect spots of hazardous weather. In the early beginnings of fighter jet design, this capability was utilized quite frequently. From the founding of non-directional beacons to modern systems, ADF’s have acted as the springboard for the VOR and GPS technologies we see today.

At Aviation Sourcing Solutions, owned and operated by ASAP Semiconductor, we can help you find all the automatic direction finder parts and aircraft cockpit parts you need, new or obsolete. For a quick and competitive quote, email us at sales@aviationsourcingsolutions.com or call us at +1-714-705-4780.


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It’s easy to neglect the little things like choosing the proper hose assembly in favor of focusing on bigger things like an engine. But, like with all things in aerospace and aviation, choosing the proper components for your hose assembly can make the difference between smooth operations or malfunctions.

Hose assemblies are used to allow movement between two port locations and to reduce the effects of vibration. Hose assemblies consist of a hose, varying in length, and a fitting, varying in length and size depending on the application in which the hose assembly is going to be placed. Hydraulic hoses consist of three main components: the tube, the reinforcement, and the cover. The tube is the inner layer of the hose, it passes information from one end of the hose to the other.  The reinforcement and the cover provide the hose with strength and durability to keep it from being damaged but force out environmental factors. Without any of these three components, a hydraulic hose wouldn’t work properly.

Fittings, the piece on either end of the hydraulic hose, are typically made from various metals such as stainless steel, brass, or carbon steel. Fittings contain two major components: a socket and a stem. The socket is the outer piece of the fitting and is used to cover the outer portion of the hose. The stem goes directly inside the hydraulic hose, this allows for the hose to connect to other components. Fittings are required to meet certain specifications such as being assembled as a matching set.

Both fittings and hydraulic hoses need to be assembled according to manufacturer standards with the proper equipment and procedures. The material that constructs the tube in a hydraulic hose needs to be selected based on the fluid that will be flowing through it. Incompatibility between the components and fluids can lead to premature degradation of the hose and result in leakage or early hose failure. 

Aviation Sourcing Solutions owned and operated by ASAP Semiconductor, should always be your first and only stop for all your hose assembly and fitting needs. We are a premier supplier of Eaton hose assemblies, whether new or obsolete. And with our wide selection of parts to choose from and expert staff, you can always find what you’re looking for, 24/7x365. If you’re interested in a quote, email us at sales@aviationsourcingsolutions.com or call us at +1-714-705-4780.



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One of the most important parts of an aircraft is the actuator or actuating cylinder. Actuating cylinders transform energy in the form of fluid pressure into mechanical force, imparting powered linear motion to some movable object or mechanism.

 Actuating cylinders are typically a cylinder housing, one or more pistons and piston rods, and some seals. The cylinder housing has a polished bore where the piston operates, and one or more other ports allowing fluid to enter and exit the bore. The piston and rod form an assembly where the piston moves forward and back within the bore while the rod moves in and out of an opening in the housing. And seals are used in various places to prevent leakages.   

 There are two main types of actuating cylinders, single-action (one directional) and double-action (two directional). In single-action cylinders, pressurized fluid enters the port from the left and pushes against the face of the piston to the right. As the piston moves, air is forced out of the spring chamber, compressing the spring such that when the pressure on the fluid is released, the spring pushes the piston left and forces the fluid out the port and air in through a vent. Single-action actuating cylinder normally use three-way control valves.

Double-action actuating cylinders are controlled by a four-way selector valve. When the valve is on, fluid can enter under pressure to the left chamber of the actuating cylinder, moving the piston to the right and thereby pushing return fluid out the right chamber and through the selector valve to the reservoir.  When the selector valve is closed, fluid pressure enters the right chamber, forcing the piston left, pushing return fluid out of the left chamber and through the valve to the reservoir. In addition to being able to move a load into position, double-acting cylinders also have the ability to hold a load in position.

At Aviation Sourcing Solutions, owned and operated by ASAP Semiconductor and a premier online supplier of aviation parts and components, we know how important actuators are. And in order to meet our client’s MRO and AOG requirements, we make sure that we stock our inventory with everything they could need, new or obsolete and hard-to-find. For more information or a quote, visit us at www.aviationsourcingsolutions.com, or call us at +1-714-705-4780. Our staff is always available and ready to help 24/7x365.


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For a lot of people, flying is terrifying. People fear that planes will suddenly lose power or that engines will fail, and planes will drop out of the sky. Fortunately, that’s a very unlikely scenario since planes have utilized redundancy and been equipped with APUs since at least WWII.

An APU, or auxiliary power unit, is a smaller engine that provides energy for non-propulsion functions, generally on aircraft, ships, and larger land vehicles. In aircraft, APUs are usually located in the very back, right below the tail. Their primary purpose is to provide power, electric, pneumatic, or hydraulic, to start the main engines. APUs also start the cabin air and electric power, serve as an emergency source of electric power in the event of engine failure, and can start the aircraft engines mid-flight in the event of an emergency. But, they’re generally turned off once the aircraft is in mid-flight.

APUs are started by a battery or hydraulic accumulator. Once they’re started, APUs generate bleed air to start the turbine engines. If the APUs fail before the engine starts, the engines can’t be started without an external start cart to provide bleed air. If the APUs fail mid-flight, there’s no immediately noticeable effect. Aircraft engines can still be restarted mid-flight without an APU, if need be, either by using a working engine to generate bleed air to start a dead engine, or by having the aircraft dive and attain enough speed to spin the turbine fast enough to start the engine. That doesn’t mean that having an APU is a bad thing.

APUs are redundant. But, that redundancy is what makes flying safer and what assuages our fears of flying. So, testing APUs for reliability and functionality is really important. APU testing facilities need to coordinate with the OEM’s in order to test APUs at various conditions and circumstances to confirm that they are performing properly. High-speed data acquisition systems and performance correction software help APU manufacturers, end users, and overhaul and service agencies get the best performance from their APUs.

At Aviation Sourcing Solutions, owned and operated by ASAP Semiconductor, we care about the safety of our customers. We strive to be the premier supplier of hard to find aviation parts and MRO services because we know that offering high-quality APUs and turbine engines at an affordable price can make all the difference.


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