FAA Powerplant Written Practice Test

What should not be used to mark high-temperature turbine engine components?

1. Paint markers

2. Pencil lead

3. Wax or grease pencil

4. Ink pens

The correct answer is: Wax or grease pencil

High-temperature turbine engine components require careful consideration when marking for identification or other purposes because of the extreme operating conditions they face. A wax or grease pencil is inappropriate for marking these components due to its potential to degrade or melt under high temperatures, leading to inaccurate information or damage to the components. In contrast, other marking methods, such as paint markers, pencil lead, or ink pens, are generally more stable and can withstand the harsh conditions encountered in turbine engines. For example, paint markers use specialized high-temperature paints that are designed to endure extreme heat without deteriorating. Pencil leads (graphite) and ink from certain pens can also maintain their integrity better in high-temperature environments than wax or grease, which could become compromised. Thus, for marking high-temperature turbine engine components, it's essential to choose materials that will last and remain legible even under challenging conditions, making wax or grease pencils a poor choice.