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 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 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 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 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 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 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, 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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Airplane landing tires are made to withstand hitting the tarmac at speeds of 170 mph, with a weight load of about 38-tons, and can tolerate about 500 landings before needing a re-tread.  Contrary to common beliefs, airplane tires are NOT going to explode if given a little too much air. 

Most airplane tires are inflated to 200 psi – compare that to our car tires which typically are around 33-34 psi.  When the plane’s tires first touchdown on the runway they are skidding, not rotating.  The force of the tires rotational velocity matches the planes velocity, causing them to skid and smoke.  Michelin uses grooves on their airplane tires, instead of the block patterns that you see on car tires.  Most of the wear and tear on airplane tires come from the initial moment of contact; if there were block patterns on these tires, the force of the contact would break them off, making them unable to properly stop.

A Boeing 777 aircraft requires 14 tires, Airbus’ A380 uses 22, and the Antonov An-225 needs 32.  The reason these aircrafts’ functionality is so efficient is because engineers have learned to maximize air pressure. 

Lee Bartholomew, lead test engineer for Michelin Aircraft Tires states, 

"It is almost impossible to blow out a tire by over inflating it and that cases where tires have been over-inflated, the wheel actually fails before the tire."

These tires must go through extensive tests to ensure they are suitable for flight.  Tires must be able to withstand four times their rated pressure for minimum of three seconds to be deemed satisfactory.

Aviation Sourcing Solutions is an online distributor of hard to find aviation parts and MRO services.  With a continuously increasing inventory, you can be sure Aviation Sourcing Solutions services will have everything you need and more.  Aviation Sourcing Solutions will ensure all needs are addressed in a timely and professional manner.  Aviation Sourcing Solutions is known for being a Boeing aircraft parts supplier that can always help you find cost-effective solutions for hard-to-find Bearing parts. For a quote, reach out to the main office by phone: 714-705-4780 or by email:

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Hand-Operated Fuel Pumps, or wobble pumps, are double-acting pumps that transfer fuel manually with each pump of the handle.  There are wide passages within the pump that allow for a back-and-forth movement of fuel. Hand-operated pumps require fuel lines to be run into the cockpit, which could potentially be hazardous.

Centrifugal Boost Pumps are the most common type of auxiliary fuel pump used on an aircraft.  These are electric motor driven, and usually located within the fuel tank or on the outside with the opening of the pump extending inside of the tank.  In this case, pump removal valves are typically installed so the pump can be detached without having to drain the entire tank.

Ejector Pumps are used to help ensure liquid fuel is always at the pump’s inlet, maintaining a constant flow of fuel from the pump to the tank.  These make sure vapor pockets do not form, which could cause structural damage to the aircraft.

Pulsating Electric Pumps, or plunger-type fuel pumps, are commonly used for smaller aircraft because they are less expensive and work the same as centrifugal fuel pumps on larger aircraft. These pumps use a plunger mechanism to pull fuel in and out; during starting they provide fuel before the engine-driven pump kicks in and can be used at higher altitudes to prevent vapor lock.

Vane-Type Fuel Pumps are the most common fuel pumps used for reciprocating-engine aircraft. These pumps can be used as engine-driven primary fuel pumps and as auxiliary/boost pumps.  Vane-type pumps ensure a consistent amount of fuel is kept moving; this can sometimes cause fuel levels to be too high, so most vane pumps have a pressure relief feature that helps with regulation.  The relief valve setting adjusts automatically to provide the correct amount of fuel as air pressure changes due to altitude or turbocharger outlet pressure.

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