Aerospace Purchasing Blog

When flying or designing an aircraft, it is always crucial that it is designated as an “airworthy” part. Airworthiness refers to an aircraft’s ability to be considered safe for flight. These standards and certificates are regulated and upheld by various international agencies, including but not limited to the International Civil Aviation Organization, European Aviation Safety Agency, NATO, and European Defense Agency. These requirements for airworthiness are not just for the aircraft, but even for each and every component as well. When sourcing parts, one may recognize some of the common standards, such as TSO and PMA, but what do these designations mean for the parts they encompass?
 
A technical standard order (TSO) part is a designation provided by the Federal Aviation Administration (FAA) to denote a part that has been deemed airworthy. FAA TSO parts must meet set out minimum performance standards for use on civil aircraft, and often are designed to replace an original part. For parts to be considered “TSO parts” by the FAA, they need to have both their design and production approved. When a part is approved to be a technical standard order part, the manufacturer may produce the part and able it as such. Despite this, it does not mean that the part is permitted to be installed onto an aircraft, as it must then be proven airworthy by the FAA for the specific intended model.

TSO parts can become canceled or withdrawn at the behest of the FAA given certain circumstances. If the FAA determines that a part is inactive, they will cease to issue new authorizations on the part and it will be considered a “canceled TSO”. Nevertheless, the approved part can still be produced but just will not be able to receive any new authorizations. If the FAA decides to revoke authorization on the other hand, it is considered a “withdrawal of a TSO authorization” and the part may no longer be produced legally.
 
Parts manufacturing approval (PMA) refers to another designation given by the FAA to parts that they have considered airworthy. PMA parts are most often those that are for replacing an Original Equipment Manufacturer (OEM) part. The process of being awarded designation as a PMA part is fairly rigorous, as a PMA part is one that is considered “equal to or better than” the OEM that it is to replace. The process first entails having the FAA determine whether or not the part meets airworthiness standards. If the part passes this stage, it must then undergo inspection and then the part will have to have instructions for repair, inspection, and continued operational safety plans.
 
While both technical standard order and parts manufacturer parts refer to replacement parts that the FAA has considered airworthy, the two still have some distinct differences that set them apart. For one, PMA parts must have sufficient documentation addressing where the part is to be used on the aircraft and will have a letter and packaging stating the same. With TSO parts, there is no direct indication required for where the part is installed. Further separating them, PMO parts are strictly tested to be the same or better than the part it is intended to replace. A TSO part, on the other hand, simply has to meet basic FAA requirements

Airspeed Indicators (ASI) are flight instruments used to measure the airspeed of an aircraft. They function either electronically or via a pitot-static system and are crucial to the safe operation of an aircraft. Because of this, pilots must be able to ensure their ASI is accurate and functioning properly. Electronic ASIs provide the peace of mind that readings will be accurate, but typically only newer, more sophisticated aircraft will feature an electronic ASI. For all other aircraft, a pitot-static system will be in use. In this case, to ensure reliability, the ASI must be calibrated and maintained regularly.
 
In addition to calculating pressure plate, the ASI provides measurement uncertainty - essentially the margin of error. Because of the different types of airspeed such as indicated airspeed, calibrated airspeed, true airspeed, and ground airspeed, pilots and technicians must know what is an acceptable margin of error and what is not. More frequently calibrated ASIs will provide a calculated and therefore more reliable uncertainty measurement.
 
It is important to realize what a delicate piece of machinery an ASI is. Seeing as it is a highly sensitive pressure gauge assy, the best option is to allow a professional to calibrate it for you. Improper calibration can cause serious damage to your ASI and result in a heavy financial blow. Should you choose to calibrate it yourself, follow these six steps:

 
Once again, calibration of your ASI is not a job that should be taken lightly, and sending the instrument to lab professionals is the best way to ensure your product will be properly calibrated.

Within piping and hydraulic systems, valves are an important component that allows for the controlling of liquid flow. Utilizing a valve, the flow of liquid can be started, stopped, redirected, sped or slowed down, or be regulated in regards to its flow. The more complex the system of piping is, the harder it can be to manually manage it in its entirety. Some systems may even prove to be dangerous to handle manually due to extreme temperatures or that the pipe houses chemicals. Complex system may also require very precise changes in which accurate control is of utmost importance. For these systems, servo valves are a great solution that allows for easy and efficient piping management.
 
Servo valves can be controlled through the use of low powered electrical signals that are sent out remotely from a control panel and transformed into a hydraulic output. Through this, change of pressure, rerouting, and starting and stopping flow can all be done efficiently and digitally. When the electric signal is sent out, it increases in strength through the use of amplifiers until the servo valve actuates the change that is desired. As systems with servo valves are closed loop systems, accurate responses of command can be achieved through feedback being directed to the servo valve.
 
Servo valves best benefit systems in which there is a need or desire for very high accuracy and control. Within the aerospace industry, servo valves benefit multiple aircraft systems. For the engines, servos work to regulate the amount of fuel that flows from the tank and into the engine for combustion. Fly by wire aircraft such as the Boeing 787 and certain Airbus models also utilize servo valves in order to control their control surfaces.

Fasteners are often some of the most important parts for the construction of aircraft and equipment. At their most basic, they secure two or more components together in a non-permanent fashion, restricting motion relative to the attached component and include hardware components like screws, nuts, bolts, rivets, and more. Flange mount bearings are a specific type of bearing fastener, and are important for applications where a shaft is perpendicular to the surface it is being mounted upon. Common applications for flange mount bearings include HVAC belt drives, conveyors, food processing machines, and more.
 
When shafts are perpendicular to a surface, there is often harmful amounts of vibration that can be caused through flex, and flange mount bearings aid with their superior ability to support loads when four-bolted, down to simple two-bolts which can support smaller loads. The bearing types that they utilize are often either roller bearings or ball bearings. Roller bearings are a popular anti-friction type in which balls rotate on inner and outer races in order to redistribute outer load of component onto the rollers. Ball bearings are similar, in that they work to reduce friction between components, as well as support their loads.
 
Flange mount bearings often feature a housing unit in which the bearing can rotate within a contained environment that is sealed to prevent outside contaminants from getting in. The housing is usually bolted down while the outer ring remains stationary. Housing types include those such as zinc die cast, pressed steel, stainless steel, and UHMW-PE depending on the desired qualities such as corrosivity and weight. These bearings also are highly beneficial in linear motion applications that require high precision

An aircraft adheres to similar principles of flight that birds do — it must overcome gravitational forces to achieve lift. In its simplest definition, the wings of an airplane curve the flow of air around them in order to generate lift.
 
Isaac Newton created three laws of motion that are applicable to all moving objects — even aircraft. The first law states that objects remain at rest or uniform motion unless they are compelled to change by an external force. The second law states that force is equal to the change in momentum per the change in time (F=ma). The last law states that for every action, there is an equal and opposite reaction. These scientific laws are important in understanding how and why aircraft can fly. 
 
Lift is created mostly around the wings because the air flows over the top of the wing and directs the air downwards. This is why wings are designed to tilt from the horizontal plane of the aircraft. This is commonly referred to as the path of flight. Once an airplane is going fast enough, the downward air-flow starts produces enough pressure or force to overcome the weight and gravity that is holding the airplane to the ground. An airplane can achieve flight when enough force is produced to overcome weight and gravity.
 
The most important variable in generating lift is the tilt angle, or angle of attack. A pilot adjusts the angle of attack to control lift: too high of an angle of attack will stall the airplane— this is called the critical angle of attack. It is the difference between pitch angle and flight path angle when the flight path angle is referenced to the atmosphere. An airplane can reach a high angle of attack even with the nose below the horizon, when the flight path angle is a steep descent. 
 
Another famous contributor to the laws of aerodynamics was Bernoulli; he stated that pressure is reduced as air increases in velocity. As air flow comes into contact with the leading edge of a wing, it splits into two, flowing along the upper and lower surfaces. Because a typical aircraft has a cambered wing, the air will flow faster over the top and slower on the bottom; this means that there is higher pressure on the bottom surface of the wing. As the airplane gathers speed, the amount of lift increases.
 
Another important component of wing design is aircraft ailerons. This structure is a hinged section close to the trailing edge of the wing that allows pilots to bank the aircraft left or right. They work in opposition with one another; as moves upward, the other moves down. This creates an unbalanced side force component which causes the aircraft’s flight path to curve. With greater downward deflection of the airflow, the lift will increase upward.
 
One last important force is drag, the aerodynamic force that creates resistance against the forward motion of a plane. Thrust is generated by the engines to overcome drag and is supplemented by the aerodynamic shape of an aircraft. It’s important to remember that an aircraft is designed to balance out contradictory forces. All components contribute to the flight cycle— whether it be the engines, the wings, the empennage, etc. The next time you see an aircraft, take a moment to admire the brilliance of its wings. 
 
At Aerospace Purchasing, owned and operated by ASAP Semiconductor, we’re always available and ready to help you find all the aviation parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@aerospacepurchasing.com or call us at +1-412-212-0606.

Aviation parts are strictly regulated by the Federal Aviation Administration (FAA), whom are involved in all parts of manufacturing and distribution. Original Equipment Manufacturers (OEMs) or manufacturers with a Parts Manufacturing Approval (PMA) may produce aircraft parts.
 
After an OEM manufactures a part, the FAA uses an FAA approved method called Test & Analysis, or Test & Computations, to deconstruct the part and create their own production drawing to produce a PMA replacement part. The parts function, application, and criticality are studied, and the result will display the necessary dimensions, features, and characteristics of the part. PMAs can be considered a FAA manufacturing license that conveys the airworthiness of an aircraft part. 
 
The FAA emphasizes the importance of safety and instills safety standards to protect the lives carried aboard an aircraft. So, it’s not enough to just produce a part that mimics the original part, it must also meet FAA standards that shows its function and durability. A PMA part has a requirement to disclose to the FAA where the part will be used on the aircraft.
           
A, FAA airworthiness approval for a part can also come in the form of a Technical Standard Order (TSO). To obtain a TSO it is only required to follow minimum FAA mandated standards and requirements. In order to obtain an FAA PMA approval, the applicant must prove that their part is equal to or better than the original part.
 
Because parts are highly regulated by the FAA, it is safe to use parts other than the OEMs. However, it’s important to pay attention to the parts history and airworthiness to make sure it was produced according to the proper FAA standards. Parts should have appropriate documentation and labels that disclose this information.
 
At Aerospace Purchasing, owned and operated by ASAP Semiconductor, we can help you find all the aircraft parts you need, 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@aerospacepurchasing.com or call us at 1-412-212-0606.

Airports are one of those types of places that don’t make any sense, or, at least, to the untrained eye they don’t. For all the chaos that happens in the terminals, especially around security screening and luggage claims, the chaos of the tarmac seems so much worse. In fact, the chaotic nature of the tarmac isn’t just worse, it’s incredibly expensive and has now become a bit of a priority to address.

From the landing and departing planes, the shuttles carrying passengers to and fro, and the hustle and bustle of the various different ground support crew and their equipment, there’s a lot happening on the airport tarmac. Especially with the ground support crew and their equipment. Ground support equipment, or GSE, is a broad range of equipment used to service and support aircraft operations, especially used near the terminals when the aircraft is on the ground between flights. They involve everything, including ground power operations, aircraft mobility, cargo/passenger handling and loading, catering, security, and more. Which is why accidents are dangerous and aplenty.

According to a 24-month long study from 2014 to 2015 with 80 aviation departments and fixed-base operators (FBOs) conducted by business aviation consulting group VanAllen, GSEs are incredibly problematic and happen far too often. The study concluded with a total of 64 accidents totaling $12.3 million. The resulting projected cost per accident for 2016 was estimated to be about $586K per accident at about 21 predicted accidents. And, off these accidents, 33% were towing accidents that were otherwise completely avoidable.

These numbers are alarming, so, it’s rather obvious why GSE accident prevention is such a priority. Airliners and airports want to reduce and prevent accidents as much as possible because efficient GSE operations ensure that schedules are being maintained and bottom lines are secured. The average cost of a GSE accident was nearly $400,000 back in 1998, taking only into consideration potential aircraft damage and lost revenue. Accidents also don’t just cost time and money, they are dangerous; it could be potentially life-threatening if ground support crew or passengers are involved in the accident.

So, there’s an incentive to train ground support crew and personnel on safety, how to move about the tarmac, how to handle accidents and emergencies, and so on. However, There are challenges to this too. In order to train ground support crew effectively, they will have to be subjected to hazards and dangerous situations on the field, instead of in the classroom. They need to be able to develop decision-making skills and response times with ample practice; the learning environment is difficult to model and simulate. But, it should all be worth it in the end. Afterall, investing money into better GSE training solutions is significantly better than losing an unknown amount of money to GSE accidents.

At Aerospace Purchasing, owned and operated by ASAP Semiconductor, we can help you find all the GSE tooling parts and FBO parts you need, new or obsolete. As a premier supplier of parts for the aerospace, 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@aerospacepurchasing.com or call us at +1-412-212-0606.

All aircraft are fitted with some form of a direct current electrical system (DC) which generates, transmits, distributes, and stores electrical energy. These systems usually operate at 14- or 28-volts.  Aircraft electrical systems are an integral component to an aircraft because they provide it with power.  Most of these systems consist of the below components:

Alternator/Generator
      Supply electric current to the electrical system
      Maintain charge in the battery
      Produce alternating current (AC) and convert to direct current (DC)
      Provides a source of power
      Used to start the engine and backup the generator

Master/Battery switch
        Controls electrical power to the aircraft
        Split into two functions: left switch controls the alternator and the right switch controls the battery

Alternator/Generator switch
        Allows the pilot to eliminate the alternator from the electrical system
        Used in the event that the alternator goes into failure

Bus bar/Fuses/Circuit breakers
        Bus bar – used as a terminal that connects the main system to the equipment; provides a common point for voltage to distribute throughout the electrical system

        Fuses –Protect from electrical overload; replaced once they are burnt out

        Circuit Breakers –Also protect from electrical overload; Can be manually reset instead of replaced

Voltage regulator
        Controls the rate of charge to the battery

        Stabilizes alternator/generator electrical output

Ammeter/Loadmeter
        Ammeter –Indicates condition of charging system; A negative indicator reflects more current being drawn from the battery, a positive indicator means there’s a regulator malfunction

        Loadmeter –Reflects percentage of load that is placed on the generating capacity of electrical accessories and the battery; When all other electrical components are off, it shows the amount of charging current required by the battery

 Warning light
        Indicates discharge in system
        Any movement of current between the battery and alternator will cause the light to power on.

Aerospace Purchasing, owned and operated by ASAP Semiconductor, is the premier supplier of aviation components.  With a constantly expanding inventory, you can be sure Aerospace Purchasing will have everything you need and more.  Aerospace Purchasing is known for finding cost-effective solutions for hard-to-find aircraft components. We’re available and ready to help 24/7x365.  For a quote, contact our main office by phone: +1-412-212-0606 or by email: sales@aerospacepurchasing.com