How to Inspect Aircraft Spark Plugs

Almost every certificated aircraft is equipped with two spark plugs per cylinder. This redundancy is provided for basic safety and for a more efficient ignition. The purpose of the spark plug is to ignite the fuel/air mixture and to create a spark gap between the center electrodes. If one of the spark plugs fails, it can cause an aircraft to shake or fly in an uncontrolled direction. In addition, it may result in large loss of power. Therefore, it is essential to inspect the plugs on a regular basis.

It is recommended to replace the plugs at least once every 100 hours. This is a good time to check for any cracks in the lead shielding barrel and to make sure that the insulator at the firing end is not cracked or nicked.

Aside from the above-mentioned inspections, the plugs should also be degreased with petroleum solvent. Then they should be cleaned using a brush or a cleaning solvent. After this, they should be dried with a dry air blast.

It is important to note that aircraft engines operate at a much higher speed and pressure than automobile engines. As a result, the electrode materials must be able to withstand high temperatures. Champion Aerospace spark plugs offer excellent resistance to heat erosion. They also have two layers of corrosion protection: a fired glass seal resistor and an aluminum oxide insulator.

These plugs can be purchased for $20 to $40 per plug. The price is often discounted if a customer buys twelve plugs. If you are not sure about which type of plug is right for your aircraft, you can find a plug tester. This device allows you to test the voltage and temperature of your spark plugs. The tester will also help you determine how well your plugs are performing.

Several factors affect the wear and tear of aircraft spark plugs. Carbon deposits on the plugs reduce their effectiveness. It is also common for the plugs to develop an oil film. This coating on the plugs may cause a problem in aircrafts that are operated on ground ops. In addition, it is possible for the plugs to become foul if the mixture is rich during descent. If this happens, it is important to aggressively lean the mixture to avoid carbon fouling.

The most common type of plug is the massive electrode plug. This plug has a thick nickel alloy side electrode that extends toward the center electrode. These plugs have a lifespan of 300 to 500 hours. They can be discarded when the electrode wears down to less than half of its original length. The plug is usually oval in shape.

Another plug type is the fine wire electrode plug. It is a relatively new technology. This type of plug has a more open architecture. It is also more resistant to erosion than the massive electrode plug. This type of plug is cheaper than the massive plug and may last up to three times longer.