ASAP Parts 360 Blog

Aircraft bearings are a very useful type of fastener, allowing for constraint of movement to specific motions, all while reducing friction between the moving parts. This requires that bearings be accurately installed, lest the bearing’s life expectancy be cut short along with other problems. If a bearing is too loose, movement between components is less restricted, leading to problems such as wear, fretting, scoring, fracturing, and more. When a bearing is too tight on the other hand, increased force for mounting may be required, also leading to possible bearing fractures. According to estimates, about 16% of premature bearing failures are caused by poor installation of bearings. So what are some of the methods to correctly install a bearing, and what are things to avoid?
 
The two main methods of bearing mounting is through what is referred to as “cold” and “hot” mounting. Cold mounting, otherwise known as mechanical mounting, is mostly used for bearings that range from small to medium. Hot mounting utilizes hydraulics for installation and is more recommended for larger bearing mounting. By utilizing these techniques and using the right fitting tools, correct installation can be done easily, and will help to avoid problems that may arise in the future, extend the life expectancy and performance of the bearings, as well as decrease the amount of downtime for machinery due to repair caused by improperly installed bearings.
 
With cold mounting, using the correct fitting tools can protect the bearing from receiving force damage and ensure a proper amount of force is used during aircraft mounting. With cold mounting, the mistake many people make is to use hammer and pipes, which can lead to damage of the raceways, as well as allows for contamination, such as dirt, to enter the bearing and lead to friction. The bearing’s rolling element can also face damage if the pipe slips during installation.
 
With hot mounting, preheating the bearing can be very beneficial as it allows the inner ring to expand, thus making installation easier. This method also avoids dirt contamination as well as serves as a quick method of mounting. Mistakes that lead to improper hot mounting is through utilizing hot oil baths, which can lead to contamination of the bearing, or by using open flames which can be dangerous in itself. Standard protocol recommends heating through the use of induction before the bearing is installed, allowing for efficiency, safety, and control during the mounting process.

Running out of fuel while driving a car can be a frustrating experience and mean a wasted afternoon. Running out of fuel while flying an aircraft, however, can verge on disastrous. For the aviation industry, proper fuel quantity indication is incredibly important, given the human lives and millions of dollars of property that can be put at risk if a commercial airliner runs out of fuel mid-flight.
 
However, measuring fuel levels can be a deeply challenging task. Changes in altitude during flight can affect the volume and density of liquid fuels, which are normally useful metrics for fuel level sensing floats within the tank or capacitors. Turbulence can also agitate fuel, leading to similar difficulties, and larger aircraft with two engines and two or more fuel tanks simply compound these issues. Therefore, pilots are trained to gauge the remaining fuel themselves by taking into account the amount of fuel on takeoff, along with the average rate of engine consumption for the speed and altitude they are flying at. This can give pilots an accurate picture of how long their aircraft can remain in the sky. However, malfunctions like fuel leaks, fuel line blockages, or excessive fuel consumption because of an engine malfunction can obviously change the rate of consumption, so pilots must compliment their own calculations with the fuel level sensors.
 
Many smaller aircraft utilize float level gauges that feed information on the fuel levels based on magnetic couplings and potentiometers to the pilot, while larger aircraft with more complicated fuel systems rely on a network of capacitance probes. These capacitors are mounted in the fuel tank, and as fuel is consumed and enters the tanks through special vents, the tank’s capacitance alters, allowing tank levels to be calculated by the on-board computer. Multi-level fuel sensors can be employed to indicate dangerously low tank levels to the pilot, and as a redundancy precaution in case one sensor fails. Fuel systems can also rely on pressure and temperature sensors to ensure proper rates of fuel injection, and to prevent harmful condensation.
 
At ASAP Parts 360, owned and operated by ASAP Semiconductor, we can help you find all the fuel gauge systems and 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@asapparts360.com or call us at 1-708-387-7800.

Aircraft seals are essential to prevent fluid buildup and to keep the system clear of air and dirt. Each seal or seal type is unique to each installation. The reasons for this include different pressure rates, the type of fluid used, the type of metal used, and the type of motion the system does.
 
There are 3 classifications of seals; packings, gaskets, and wipers. Hydraulic seals will either be called packings if they are used internally on moving equipment or gaskets if they are used on stationary equipment. The different type of packing seals and gaskets we will cover in this article will be V-rings, U-rings, O-rings, and backup rings.
 
V-Ring packings are one-way seals open “V” facing the pressure. After installation, V-rings must have a male and female adapter to secure them in place. Along with this, it is necessary to torque the seal to the amount indicated in the CMM or else it will not perform to the standards it should.
 
U-Ring packings and U-cup packings are used in brake assembly and master cylinders. For this ring the seals pressure can only operate in one direction, so it is critical to face the lip of the packing toward the pressure. The U-ring and cup are low pressure packings, operating below 1,000 psi.
 
The O-ring is the most common form of packings and gaskets on aircrafts. Circular with a truly round, small cross-section, the O-ring packing is able to seal in both directions. The O-ring is very versatile. It was originally created under the Air Force-Navy and used with fluids operating at temperatures all the way from -65 degrees Fahrenheit to +160 degrees Fahrenheit. The newest models of the O-ring can operate at temperatures up to +275 degrees Fahrenheit. Under Military Standard specifications, newer models are being designed and tested to withstand low-temperature performance without compromising the high-temperature values.
 
Backup rings can withstand the test of time, chemical interference, and extreme temperatures and pressures due to their Teflon exterior. Backup rings are interchangeable and can be switched between any Teflon ring with the same dimensions. For installation, backup rings should be placed below the O-rings to ensure proper functionality.
 
A gasket’s main purpose is to form a stationary seal between two surfaces. These are commonly made from asbestos, copper, cork, or rubber. Caution should be used when working with rubber sheeting and should not be mixed with gasoline or oil.
 
To help identify the many varieties of packings and gaskets, there is a color code system. Packings or gaskets that are capable to be used with Skydrol fluid are coded with a green stripe. Colors can also indicate fluid compatibility; red signifies fuel and blue signifies hydraulic fuel.
 
When installing O-rings, precautions should be taken with the tools being used or anything that may cause a scratch or damage to the component surface. Contact with the cylinder walls, piston heads, and related precision components is also not recommended. O-rings should be inspected for any defaults of defects. After inspection, O-rings should be cleaned in hydraulic fluid. Perform installation with care while avoiding twisting or excessive movement.

Just as a car requires a vehicle registration number and plate to be airworthy, an aircraft must feature a data plate. Issued by the aircraft manufacturer, aircraft data plates are not something that you want to replace. They are notoriously hard to come by and are attached to a string of FAA regulations.
 
The Code of Federal Regulations (CFR) section 14, part 45, Identification and Registration Markings, sets out all the FAA requirements concerning the legitimacy of aircraft data plates. There are a number of details that need to be included on the plate: the builder’s name, model designation, builder’s serial number, type of certificate number, and, if applicable, the engine rating must all be noted on the plate.
 
Typically, the data plate is set out with the required information heading on the left accompanied by a text box filled in with the aircraft specific data. Rather than a simple car registration plate where the registration number is centered, the data plate looks more like a filled-out metal form. The FAA also dictates the type of material that should be used to make the plates. As the data plate is required to be fireproof, durable, resistant to corrosion, and lightweight, there is little choice in terms of appropriate material. Metalphoto photosensitive anodized aluminum is a popular choice for data plates as the image is sealed beneath a sapphire-hard anodic layer. Data plates should be appropriately secured to the aircraft fuselage so that is legible to a person on the ground. It must also be adjacent to the rear-most entrance door or on the fuselage surface near the tail surfaces.
 
Many pilots and airlines despair at the thought of losing their aircraft’s data plate. Due to the various regulations surrounding data plates, it is difficult to source a new, legitimate plate for your aircraft. Aircraft manufacturers are hesitant to distribute plates as they are cautious of product liability exposure. Manufacturers also often go out of business, meaning that an aircraft owner has no choice but to look elsewhere for a replacement. Plates are therefore in high demand, leading to the proliferation of counterfeit plates. The FAA is not too helpful in light of this dilemma. Their official statement encourages the owners to purchase plates from an approved source, but first they must contact the local Flight Safety Standards District Office for approval and assistance.
 
It may seem like a resourceful idea to purchase an identical out of service aircraft and simply take the plate off and affix it to your new aircraft. Although sound in logic, this practice is warned against within the aviation world. The FAA has a strict policy concerning the removal and replacement of data plates. CFR 14 45.13 e specifies that no person can remove or install a plate that has been previously approved on another aircraft.
 
Data plates are essential to the airworthiness certification of an aircraft. If an aircraft has a missing, counterfeit, or switched plate, an FAA-appointed inspector will ground your aircraft, effective immediately.