Over the course of a product’s life cycle, the device may require certain changes. Before these changes can be made, a manufacturer must acquire a PMA (Premarket Approval) supplement. A PMA supplement is the submission required for a change regarding the safety or effectiveness of a device for which an applicant already has an existing PMA. Similar to PMA supplements, PMA amendments include all additional submissions to a PMA or PMA supplement prior to approval of the PMA, PMA Supplement, or all additional correspondence after the PMA or PMA supplement.

The type of PMA submission depends on a number of factors, the most common of which is the data needed to demonstrate the safety and effectiveness of changes. Despite this, there are many different changes that require a PMA supplement as well as a number of types of PMA supplements. This blog will explain the changes that trigger the need for a PMA supplement, as well as a few of the many types of PMA supplements.

After the FDA has approved a PMA, the applicant must submit an PMA supplement for review and approval before making the proposed changes. Changes for which an applicant must submit a PMA supplement are vast, including but not limited to:

  • New indication for use of the device.
  • Labeling changes.
  • The use of a different facility for the manufacturing, processing, or packaging of the device.
  • Changes in manufacturing methods or quality control procedures.
  • Changes in sterilization procedures.
  • Changes in packaging.
  • Changes in performance or design specifications, circuits, components, principles of operation, or physical layout of the device.
  • An extension of the expiration date of the device based on data obtained under new or revised testing protocols that have not been approved by the FDA. If the protocol has been previously approved by the FDA, a supplement is not needed but the change must still be reported to the FDA.

While there are many types of PMA supplements, the four most common are the PMA Panel-Track Supplement, PMA Supplement (180 Days), Real Time Supplements, and Special PMA Supplements. Panel-Track Supplements are specific to changes that request a significant change in design, performance, or usage of the device. To gain a panel-track supplement, substantial clinical data of assurance of safety and effectiveness is required. 180-day PMA supplements are required for changes relating to the safety and effectiveness of a device, as well as changes in the components, materials, design characteristics, specification, software, or labeling.

Real time supplements are needed when a minor change to a device, such as a change in its design, is requested and the FDA has granted a meeting or similar exchange to review the status of the supplement in real time. Special PMA supplements are required when any changes enhance the safety of a device or the safety in use of the device, or for certain labeling and manufacturing changes that enhance the safety of the device. Special PMA supplements can be placed into effect by the applicant prior to the receipt of a written FDA order approving the PMA supplement.

PMA supplements are critical in any highly-regulated industry. At Aerospace Unlimited, owned and operated by ASAP Semiconductor, we can help you source all types of FAA PMA supplements parts through our PMA supplement list and deliver them with some of the industry’s best lead times. 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@aerospaceunlimited.com or call us at +1-412-212-0606. Our team of dedicated account managers is standing by and will reach out to you in 15 minutes or less.


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Within a plumbing or fluid system, valves are important components that are implemented to regulate, control, and direct the flow of fluids within the system. Solenoid valves are a special type of valve that is operated electromechanically, and they may perform many of the same functions of a standard valve automatically. With various types available that offer diverse sets of capabilities, solenoid operated valves may benefit a number of plants, equipment, and applications. In this blog, we will discuss the functionality of solenoid valves, as well as the applications that they benefit.

Unlike standard valves, solenoid valves do not need to be operated manually, and thus they open up the capability of remote control to serve as externally piloted valves. The main components that form the solenoid valve assembly are the subassembly, core tube, bonnet, hanger spring, backup washer, diaphragm, disk, and valve body. Within the solenoid subassembly, there is typically a retaining clip, solenoid coil, core tube, plugnut, shading coil, core spring, and core. Altogether, these parts provide for the automatic control of fluids within the system.

Solenoid valves operate by opening and closing orifices within the body of the valve, either permitting or denying the flow of fluids. The opening and closing of these orifices is done by the plunger within the sleeve tube that is actuated by a magnetic field. Such magnetic fields may be produced by having a current run through the coil of the solenoid, energizing it to create the magnetic field. This magnetic field and energizing of the solenoid is harnessed to convert electrical energy into mechanical energy for valve operations. The seals of a solenoid valve may be metallic or rubber, and electrical interfaces may be present to create an ease of control.

The main benefit of a solenoid valve is the ability to remotely control functions, as well as permit more complex processes within a system. Solenoid valves create the ability to easily shut off, release, dose, distribute, and mix fluids within a system. On top of their capabilities, solenoid valves also tout high reliability and service lives, as well as permit fast switching, low control power, and are compact in design.

Within industries and applications, the use of solenoid valves may range from simple on and off control of dishwashers to plant control loops. Common uses of solenoid valves include applications such as water supply, fuel supply, wastewater treatment, oil and gas burner control, blood analysis instruments, gas mixture regulation, pressure relief and drainage, large heating systems, machine engineering, and much more. Depending on the application, various solenoid materials may be used, such as brass, stainless steel, aluminum, and plastics. Solenoid valves may also be direct current or alternating current powered, as well as may be one or two solenoid valves. Since their debut in the 1910, solenoid valves have been greatly beneficial to a number of hydraulic and pneumatic systems.

When it comes time to begin sourcing the solenoid operated valves and aerospace components that you need for your next project or operation, Aerospace Unlimited has you covered with everything you are searching for. Aerospace Unlimited is owned and operated by ASAP Semiconductor, and we can help you find the aircraft and marine parts that you are searching for, new or obsolete.


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Aircraft are defined by their wings. The shape, size, and configuration will affect all aspects of an aircraft’s performance and specifications. Wings are airfoils, shapes designed to create lift when moving rapidly through the air. This lift, combined with the thrust generated by the aircraft’s engine or engines, is what allows an aircraft to fly.

Wings come in various different configurations and shapes, depending on the requirements of the aircraft and its intended use. A wing’s shape will determine how much lift it generates, how the aircraft controls at various operating speeds, stability, balance, and more. Both the trailing edge and leading edge of an aircraft wing can be curved or straight, and wings can attach at various points on the fuselage- bottom, middle, or on the top. There is also the wing dihedral angle, which is the angle at which the wing is set, either perpendicular, or angled up or down.

Aircraft wings are typically built in a complete cantilever design, meaning that they do not require external bracing or support, and are internally supported by structural members and the aircraft’s string. Some designs, however, do feature external wires or struts to prevent vibration and maintain structural integrity. Most wings are built from aluminum, but older aircraft will use wood frames covered in fabric. Modern aircraft often use carbon fiber materials in their construction as well. Wings typically consist of stringers and spars that run spanwise, and formers, bulkheads, and ribs that run chordwise, from leading edge to trailing edge.

Common wing shapes include:

Rectangular:

The rectangular wing is easy to manufacture, and features a non-tapered, straight design used mostly in small aircraft that extends from the fuselage at a 90 degree angle. However, rectangular wings are not very aerodynamically efficient.

Elliptical:

These wings are very aerodynamically efficient and induce minimal drag. However, they are very difficult to manufacture. Elliptical wings were originally designed for military aircraft to house landing gear, guns, and ammunition inside a wing. The ellipse shape was designed to offer the thinnest possible wing, all while holding all these components.

Tapered:

Created as a compromise between elliptical and rectangular designs, tapered wings feature a chord that gradually grows smaller closer to the tip. While not as efficient as elliptical wings, tapered wings offer a compromise between efficiency and manufacturability.

Swept-wing:

Most modern aircraft feature swept-back wings, as they reduce drag and maintain controllability while flying at transonic speeds.

Delta:

Essentially a massive triangle-shaped wing, delta designs are a very low aspect ratio wing used in supersonic aircraft. Delta wings are efficient in all phases of flight, subsonic, transonic, and supersonic, and offers a large surface area which improves maneuverability and reduces wing load. Delta wings are also structurally sound, possess a large volume for fuel storage, and are simple to manufacture and maintain. However, delta wings create lots of drag, and at low speed operations they force a high angle of attack because of vortices creating lift, which makes take-offs and landings challenging.

Variable sweep:

These designs feature wings that are mounted on mechanical hinges that let them alter their profile mid-flight that can sweep the wing back and forth. This lets the wings alter their profiles to be more suitable for low speed or high speed operations. However, these wings are very mechanically complex, and require lots of maintenance.

At Aerospace Unlimited, owned and operated by ASAP Semiconductor, we can help you find all the aircraft wing 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@aerospaceunlimited.com or call us at 1412-212-0606.


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Aching legs, weird humming noises, squeezing past other people to get to the restroom— these discomforts describe the features of a bad aircraft seat, and rest assured, we’ve all been there. So, where is the best place to sit on an airplane? Is it worth it to pay for your seat, or to sit by your device 24 hours after booking your flight to get that “A” boarding pass? We’ll lay out all the facts using the example of a widebody aircraft so that you can make your decision with ease.

 
Let’s tackle what region of the cabin to sit in. Which is best— front, middle, or back of the aircraft? If you’re particular about noise, the front of the cabin is your best choice. On average it is quieter than the rest of the plane, and sound from the engines is most diffused towards the front. This area is also less affected by general turbulence. Pro tip, if you’re a first-time flyer or you are bringing one, sit up here.
 
Sitting in emergency seats is the best option for anyone looking for more leg room, but always be prepared to handle the responsibilities this seat may require. Exit seats with more space are located in the middle of a wide body aircraft. Last but certainly not least to some, for a cool social media photo, sit in the middle of the aircraft. You’ll have a better chance of that picturesque view of the aircraft wing.
 
When you’re looking for privacy, or the chance of an empty seat next to you, sit in the back. Most airlines load the aircraft front to back, so your best chance of available seats and overhead bins is in the rear of the aircraft. This will also give you quick access to lavatories, and usually faster flight attendant service. Now, is there really that much of a difference between a window, middle or aisle seat? Let’s dive into the specifics.
 
 If you are in a rush for one reason or another, need to get up frequently, or crave more leg room, the aisle seat is your best choice. Psychologically, it’s also better for new flyers, and anxious flyers, to sit in the aisle seat. The accessibility can help reduce general anxieties.
 
Middle seats are generally the least preferred seat on an aircraft due to their limited accessibility. However, this choice is ideal if you are saving a seat for someone, or if you are bringing a child on board. You can ensure a saved seat beside you, and people in a group are less likely to try and sit in your row. It is also the second-best choice if you know you’ll need to have regular access to the bathroom.   
 
Window seats are ideal if you’re wanting to sleep undisturbed. Flight attendants and passengers are less likely to bump you as they pass by, and noise is reduced in this area. However, shoulder room is limited near the window, due to the curvature of the airframe. If you need extra space, opt for the aisle seat instead.
 
At Aerospace Unlimited, owned and operated by ASAP Semiconductor, we can help you find the aircraft parts you need, new or obsolete. As a trusted ISO 9001:2015 certified and FAA AC-0056B accredited company, we’re committed to quality and ready to help you 24/7x365. For a quick and competitive quote, email us at sales@aerospaceunlimited.com or call us at +1-412-212-0606.


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