They may not be the most talked-about components in aviation, but aerospace grommets play a crucial role in protecting parts from damage. Also known as eyelets, they consist of a ring-shaped piece of material. Grommets are designed to reinforce holes so that wires and cables can safely run through those holes without succumbing to damage. Here are five common misconceptions about aerospace grommets.
#1) Not Important
Don’t let their simple design fool you into thinking grommets aren’t important. When used in aircraft, grommets are very important. Commercial jets, private jets and other aircraft have many different wires and cables. The Boeing 787 Dreamliner, for instance, has approximately 62 total miles of wires and cables. Grommets protect these wires and cables from damage by creating a soft, padded ring around the holes through which they are run.
#2) Same as O-Rings
While they share a similar design, grommets and O-rings aren’t the same. O-rings are used to seal mating surfaces so that fluids or gases don’t leak. Grommets, on the other hand, are used to reinforce holes and protect wires and cables from damage. Because they are used to prevent leaks, O-rings rely heavily on their elastomeric properties. They typically expand when exposed to heat, resulting in a better seal.
#3) Only Used for Electrical Wires
Grommets are commonly used to protect electrical wires from damage, but that’s not their only application. Aircraft have many other types of wires and cables that can benefit from the use of grommets. Hydraulic and fuel lines, for instance, are often run through grommet-reinforced holes. The grommets create a soft ring around the holes so that the lines don’t wear down.
#4) One-Size-Fits-All
Contrary to common belief, grommets aren’t one-size-fits-all. They are available in many different sizes. Some grommets are large, whereas others are small. When shopping for grommets, you’ll need to consider the hole or holes in which you intend to install them. The grommets must be the right size for the hole or holes. Otherwise, they won’t fit.
#5) Only Available in Rubber
Another common myth is that grommets are only available in rubber. Synthetic rubber is certainly a popular material in which grommets are made, but it’s not the only material. You can find grommets available in many other materials, including fluorosilicone and thermoplastics. When used in aircraft, grommets must be able to withstand chemicals like coolant and oil. They must also be able to withstand heavy physical wear and tear. Therefore, they must be made of a suitable material.
