A necessity in many industries, pressure transducers measure pressure and create an electrical output proportional to the input. This is done by using variable pressure sensors to measure deflection and resistance and transform that pressure into either a voltage, current or frequency.The sensing element or diaphragm is deflected due to input pressure and moves in relation to a resistor or capacitor plate that then sends an output signal based on the varying tension received by the input pressure. Most types of transducers require an electrical input called an excitation. Transducers typically produce one of three types of output: millivolt (mV), voltage (V), and milliampere (mA).

There are three main types of transducers: potentiometric pressure transducers, capacitance pressure transducers, and resonant wire pressure transducers. Potentiometric sensors are comprised of a precise potentiometer with an arm attached to a Bourdon or bellows. As the arm moves across the potentiometer, it converts the deflection into a measurement of resistance. These transducers are small in size and work great in tight spaces. They also produce a strong output, making them perfect for applications with low power. Capacitance sensors are sensitive and responsive; using a diaphragm transducer model to measure resistance. The diaphragm has a small space to travel, making it a valuable tool for low differential and absolute pressure applications. Resonant wire transducers measure pressure with a wire attached to the sensor diaphragm. Pressure changes affect the tension of the wire as it oscillates, changing the frequency at which the wire is resonating, and allowing for a more exact measurement. These transducers are ideal for low differential pressure applications.

Whichever pressure transducer you decide to use, it is important to remember two external variables that can inaccurately alter a trasnducer’s output signal: temperature and electromagnetic interference (EMI). As temperatures increase or decrease, there is a subsequent expansion or contraction in fluids and materials. This effect can change both the transducer’s mechanical and electrical properties and therefore alter its calibration. When high EMI field strengths are present, a transducer’s internal amplifier can become saturated and as a result cause inaccurate outputs. Shielding, grounding and routing techniques are implemented as a proactive measure to combat EMI interference.


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Altitude is a relatively simple concept. In general, it is defined as an object’s height relative to sea level or ground level. However, what most people don’t realize is that there are many different types of altitude. There are actually five, those being indicated altitude, pressure altitude, density altitude, true altitude, and absolute altitude.

The first type, indicated altitude, is the simplest. It is merely the altitude you read directly off of your altimeter when it is set to local pressure at sea level. It’s important to adjust your altimeter for pressure changes, otherwise the reading will be inaccurate. The second type of altitude is pressure altitude. Pressure altitude is the altitude of the aircraft above the standard datum plane, an imagined location at which the altimeter equals 29.92 inches of mercury at 15 degrees Celsius. Any aircraft flying around 18,000 feet is required to set its altimeter to 29.92 inches Hg.

Density altitude is similar to pressure altitude, but it is adjusted for non-standard temperatures. During the warmer parts of the year, it may seem like your aircraft is not performing to its usual standards. This is a result of the air becoming less dense as temperature increases. In turn, high temperatures cause an increase in density altitude, making your aircraft feel like it’s at a much higher altitude than it really is. A decrease in density of air molecules means that there is less air mass flowing over your wings; therefore, less lift is generated. For this reason, it is important to be careful of flying at high altitudes on warm days.

True altitude is the distance of your airplane above sea level. It is most commonly expressed as ‘feet MSL’ meaning feat above mean sea level. A majority of the altitudes, terrain figures, airways, and obstacles listed on aviation charts are recorded in true altitude. The absolute altitude is the distance of your aircraft from the ground. It is constantly changing as your aircraft flies over obstacles and differing terrain. Absolute altitude is expressed in feet above ground level (AGL) and is measured by timing how long it takes for radio waves to go from plane to ground and back to the plane.


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Aviation maintenance technicians rely on a wide range of hand tools in the course of their work. What tools are used depends heavily on the aircraft; a large commercial jet will have different maintenance requirements than a small general aviation aircraft, which will be different from that of a cargo helicopter. Across the industry however, there are some pieces of equipment that will be welcome in any workshop.

Hammers and mallets are typically used to form soft metals and striking surfaces that are easily damaged. Soft-faced hammers feature striking surfaces made of materials like wood, brass, hard rubber, plastic, or rawhide. They are not used to strike punch heads, bolts, or nails, as doing so can easily ruin the hammer’s surface. Instead, they are used to shape thin metal parts without causing creases or dents with abrupt corners.

Used to tighten or loosen screws and screw head bolts, screwdrivers come in numerous shapes, blade types, and lengths. A screwdriver’s head must fill at least 75% of the screw slot; if it is too small or too large, the screwdriver will simply cut and burr the screw slot, making it worthless and forcing a screw extractor to be used. Screwdrivers can also come with replaceable tips, allowing the operator to swap out one once after it has been worn down. Currently, cordless hand-held power screwdrivers are the most widely-used, as they can remove multiple screws much faster than a simple hand-driven version.

Pliers are another frequently used type of tool, with diagonal, needlenose, and duckbill the most common in the aviation industry. They are used to crimp metal, trim safety wire, and cut wires, rivets, screws, and cotter pins.

Wrenches are some of the most common tool used in aircraft maintenance, with popular types such as open-end, box-end, socket, adjustable, ratcheting, and specialized types found in repair shops worldwide. These wrenches are usually made from chrome-vanadium steel, which is chosen for its resilience and durability. Specialty wrenches such as crowfoot, flare nut, spanner, torque, and Allen wrenches are also frequently used. A crowfoot wrench, for instance, is used when trying to access nuts that need to be removed from studs, or bolts that cannot be accessed using other tools.

When a definite and predetermined amount of pressure must be applied, torque wrenches are used. A torque wrench is a precision tool that can be calculated to administer or measure the amount of turning or twisting force a nut, bolt, or screw has received, ensuring that fasteners are tightened exactly as tight as they should be.


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The commercial airline industry is highly competitive and constantly growing. Hundreds of airlines around the world are working to set themselves apart from the rest and fight for your business. While your choice of airline is seemingly limitless, your choice of manufacturer is, by comparison, very slim. It’s no question that the likes of Boeing Company and Airbus rule the skies, but there are still a few more enterprises making themselves known in the aviation industry. This blog will provide a rundown of some of the significant aircraft manufacturers in business today.

You can’t talk about airplane manufacturers without mentioning Boeing and Airbus. These two titans of industry are the world’s sole large passenger aircraft manufacturer. Boeing’s 7 series and the Airbus A-series are in use all the time in every corner of the world. The two have nearly complete control of the worldwide aircraft supply business for large commercial jets, including narrow-body aircraft, wide-body aircraft, and jumbo jets. These two are the unquestioned industry leaders, but a number of other manufacturers play a role in the aviation sector.

Two such manufacturers are United Technologies Corporation and General Electric. Both of these companies manufacture a vast collection of parts and materials used in many aircraft components. In addition to these, Canadian manufacturer Bombardier and Brazilian manufacturer Embraer are leaders in the regional and business airplanes market, both focusing on smaller jets. Newer companies are joining Bombardier and Embraer in the smaller jet market, who are far easier to compete with than Boeing and Airbus. China’s Comac, Japan’s Mitsubishi, and Russia’s UAC have all begun to make their presence known in recent years. In fact, Comac and UAC have embarked on a joint venture creating wide-body jets with the hope of one day making them a serious contender for Airbus and Boeing’s throne.


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Pressure transducers have never been more prevalent, or more reliable. With stainless steel construction and modern engineering, pressure transducers can provide overpressure protection, improved total error band, and negligible orientation and vibration effects. They are ideal for long-term use in harsh environments of extreme temperature, humidity, and vibration. However, pressure transducers can fail like any other piece of equipment. Common causes include improper wiring, incorrect polarity, inadequate power supply, multiple grounds, short circuits, operations issues, and problems with the transducer itself. In this blog, we’ll explore some trouble-shooting techniques that can help you determine just what went wrong with your transducer.

Before we begin, however, these troubleshooting guidelines assume that the person following them is a trained technician, has access to a 24 VDC power source, and knows how to properly use a digital multimeter to measure resistance, current, and voltage.

When trouble-shooting a 3-wire transducer, the most commonly used voltage transducer, the problem is most likely that there is no signal or that the signal is different from what is expected. After removing the transducer from the pipeline and control circuit, the technician needs to identify all terminals for the unit being examined. Once terminal configuration is confirmed, the technician can power the unit and check if the transmitter is operating properly through placing the voltmeter + onto the +_ signal and vice versa for the - components. If the readings are what the technician expected, then the transducer is operational.

When the 3-wire transducer is still attached to a pipeline, make sure that the +24 VDC is connected to the transducer’s + excitation, and the -24 VDC to the common. Then, disconnect the wire that runs from the transducer’s + signal to the control circuit. Place to voltmeter’s + lead onto the transducer’s + signal, and the voltmeter’s - onto common. With no pressure applied, the transmitter should provide a voltage output that is specified on the unit’s data sheet. If it does, then the transducer is functioning properly.

When troubleshooting a 4-wire transducer that has been removed from the pipeline, as well as its control circuit and terminal configuration, the technician can power the unit by connecting the +24 VDC power supply to the transducer’s + excitation and -24 VDC to the - excitation. Once the voltmeter is connected to the correct signal and no pressure is applied, the voltemeter should provide a reading that is equal to the analog signal for zero applied pressure.

When troubleshooting a 4-wire transducer that is still connected to a pipeline, disconnect the wire that runs from the transmitter’s + signal to the control circuit. Next, place the digital voltmeter leads onto the matching transducer signal. If the transmitter provides a voltage output as specified by the unit’s data sheet, then the transmitter is operational. However, if the transmitter reads 0.0 VDC, it may not be functioning, and further troubleshooting will need to be conducted.


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For many, circular connectors have become a go-to solution for automation systems because of their benefits over hardwired systems. Circular connectors are easy to use, compact in size, adaptable, and rugged enough for outdoor use. One particularly popular type of connector is the M23 connector.

The M23 connector is frequently used due to its robust design and customizable nature. Like most connectors, M23s come in male and female plugs and sockets, with power pin-outs that come in six, eight, nine, and ten poles, and signal pin-outs that come in six, seven, nine, twelve, sixteen, seventeen, and nineteen poles, and typically use orange jackets as power cables and green jackets for signals. An M23 connector can handle voltages of up to 200 V and currents of up to 8 A and has an IP67 rating. This means that it can be dropped in a body of water up to a meter deep, stay submerged for up to half an hour, and maintain functionality.

Made of nickel-plated brass, nickel-plated zinc, or a copper-zinc alloy, the M23 can also come in a variety of housings including straight connectors, right angle connectors, and panel mounts. In addition to the standard screw connection, M23 connectors are also available in the TWILOCK and TWILOCK-S quick connect system. Some manufacturers also include anti-vibration locks that prevent connectors from loosening and providing permanently sealed connections. This in turn means there is no need for re-tightening or checking if the connectors have come loose.

M23s are used in a wide variety of applications including motors, encoders, motion controllers, robotics, and conveyors. The M23 can operate in temperatures ranging from -40 degrees Fahrenheit all the way up to 257 degrees, allowing it to be used in a wide variety of demanding environments, and fulfill the needs for control signal and power transmission in a robust and compact delivery system.


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For many, circular connectors have become a go-to solution for automation systems because of their benefits over hardwired systems. Circular connectors are easy to use, compact in size, adaptable, and rugged enough for outdoor use. One particularly popular type of connector is the M23 connector.

The M23 connector is frequently used due to its robust design and customizable nature. Like most connectors, M23s come in male and female plugs and sockets, with power pin-outs that come in six, eight, nine, and ten poles, and signal pin-outs that come in six, seven, nine, twelve, sixteen, seventeen, and nineteen poles, and typically use orange jackets as power cables and green jackets for signals. An M23 connector can handle voltages of up to 200 V and currents of up to 8 A and has an IP67 rating. This means that it can be dropped in a body of water up to a meter deep, stay submerged for up to half an hour, and maintain functionality.

Made of nickel-plated brass, nickel-plated zinc, or a copper-zinc alloy, the M23 can also come in a variety of housings including straight connectors, right angle connectors, and panel mounts. In addition to the standard screw connection, M23 connectors are also available in the TWILOCK and TWILOCK-S quick connect system. Some manufacturers also include anti-vibration locks that prevent connectors from loosening and providing permanently sealed connections. This in turn means there is no need for re-tightening or checking if the connectors have come loose.

M23s are used in a wide variety of applications including motors, encoders, motion controllers, robotics, and conveyors. The M23 can operate in temperatures ranging from -40 degrees Fahrenheit all the way up to 257 degrees, allowing it to be used in a wide variety of demanding environments, and fulfill the needs for control signal and power transmission in a robust and compact delivery system.


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Keeping the engine in any aircraft cool is a critical part of maintaining performance and safety. For piston-powered aircraft, this means using a system of baffles and baffle seals to regulate airflow through the engine compartment.

In early aviation history, where aircraft were powered by uncovered radial engines, cooling was provided by having the engine’s cylinders exposed to slipstream as the plane flew. This method, known as “velocity cooling,” was good enough for low-powered radial engines. However, velocity cooling is insufficient for higher-powered and horizontally opposed engines, which are long enough that the rear cylinders get far less air than the ones closer to the front. Aeronautical engineers soon developed a new process for cooling, called pressure cooling.

The process begins at the nose of the airplane where air flows in through openings in the nose bowl (this is because engines in modern aircraft are tightly cowled to protect against the elements). Once inside, a system of rigid aluminum baffles and flexible baffle seals made from rubber work together to create a chamber of high pressure above the engine’s cylinders and a chamber of low pressure below the cylinders and behind the engines. Heat naturally rises up from the engines into the high-pressure chamber even as the baffle seals direct air from the high-pressure area to the low-pressure area. This creates an airflow that travels from top to bottom and ultimately back out the airplane through openings in the cowl.

An important component of maintaining a healthy engine temperature is making sure the baffle seals are up to date and functioning properly. Baffle seals become loose and brittle with age and eventually, can’t keep air from leaking past the seal. A warning sign for weak baffle seals is abnormally high cylinder-head temperature or oil temperature. A simple visual inspection by lifting up the engine cowl should reveal any flaws or defects in a baffle seal. Older examples tend to be thin and black, while newer seals made of rubber silicone are typically reddish orange.

At AFR Enterprises, owned and operated by ASAP Semiconductor, we can help you find all the baffles and baffle seals for the civil and defense aerospace and aviation 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 purchase@afrenterprises.com or call us at 1-714-705-4780.


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A temperature sensor is a device used to measure temperature through an electrical signal that requires a thermocouple. This electronic device consists of two dissimilar conductors (different types of metals) joined together at one end, which form electrical junctions at varying temperatures. When the junction of the conductors is heated or cooled, it emits a temperature dependent voltage formed by a thermoelectric effect, which can be used to measure temperature.

German physicist Thomas Seebeck has been credited with discovering the thermoelectric effect. He found that if two ends of a metal were sitting at different temperatures, an electric current would flow through it. He later realized that if he connected the two ends of the metal together, no current flowed. Coincidently, no current flowed if the two ends of the metal were at the same temperature. Seebeck finally used two different metal conductors and found that an electrical current was flowing through. Electrical conductivity paired with thermal conductivity is the sole proprietor in determining how well an electrical current will flow. Thus, the thermoelectric effect was discovered.

Electrons tend to move more freely in certain materials as opposed to others. This is the main difference between conductors and insulators. If you were to connect two different metals together (copper and iron), free electrons will move from one material to the other through a diffusion process. Electrons would move from the iron to the copper, resulting in the copper being more negatively charged and the iron being more positively charged. If one of the junctions was hotter than the other, electrons will readily diffuse between the metals. This means that the voltage at the two junctions will vary depending on their temperature difference.

There are many types of thermocouples such as: type K, J, T, E, N, S, R, B. Type K is the most common and has a wide temperature range. Another thermocouple that’s used frequently is Type J, which, displays a smaller temperature range. For extremely low temperatures, Type T should be used. Type E has a stronger signal and accuracy than Type K at moderate temperature ranges. Type N is a stronger and more expensive version of type K. In scenarios that have high temperatures, use Type S as it is very accurate and stable. Type R is used in high temperature applications and is constructed with a higher percentage of Rhodium. The thermocouple that can process the highest temperatures is Type B. One advantage of Type B is that it maintains a high level of accuracy.

There are some disadvantages of thermocouples. They have a tedious re-calibration system and are a bit difficult to verify. They are also susceptible to electromagnetic interference, also known as radio-frequency interference and can also be costly when trying to repair.

At AFR Enterprises, owned and operated by ASAP Semiconductor, we can help you find all your thermocouple 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@afrenterprises.com or call us at +1-714-705-4780.


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The Aerospace Industry has a new star in the Asian-Pacific— South Korea’s first MRO station, Korea Aviation Engineering and Maintenance Service (KAEMS). As of this month, the station has successfully completed its first “C-Check” on a Boeing 737 jet from Jeju Air and has another in progress on a B737 from Eastar Jet. This MRO station is a notable achievement for the aviation industry in South Korea.

KAEMS was commissioned by Korea Aerospace Industries (KAI), and 6 other Korean investors in December of 2017. The investors have future plans to expand their services to provide components and engine maintenance, gas repair, special equipment, and maintenance repairs for domestic jets and military aircraft. Located in Sa Cheon, in the South Gyeongsang Province, this MRO station has the potential to service a wide range of clients with routes through the Asian Pacific.

Demand for MROs in the Asian-Pacific has increased upwards of 40% since 2014 and is only expected to increase further in the coming years. In anticipation of growth, and to meet current demand, the investors intend for the KAEMS station to provide more than half of MRO service demand in this region by 2026. Until now, MRO service has been dominated entirely by overseas companies.

KAI is already widely known in the U.S. for its partnership with Lockheed Martin on training jets for South Korean military. Since 2016, the two companies have been pursuing a 16 billion USD contract with the U.S. Air Force to provide trainer aircraft. With commercial routes opening in Singapore and Mongolia, the KAEMS station has the potential to provide a great deal of business and notoriety to its investors.

At AFR Enterprises, owned and operated by ASAP Semiconductor, we can help you find avionic maintenance tooling parts, aircraft maintenance equipment, and avionics tooling parts, new or obsolete. As a premier supplier of 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, 24/7x365. For a quick and competitive quote, email us at sales@afrenterprises.com or call us at +1-714-705-4780.


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