Don’t Make Assumptions When It Comes To Sealants

December 2021

Making assumptions during aircraft maintenance events can have a major impact on whether a job is done properly or not. Such is the case with sealants.

Sealants come in different colors, each with a different characteristic. However, same-colored sealants are not created equal.

For example, RTV silicone sealants are high-temperature sealants that come in the color red. They have differing maximum temperatures and are often called out in different specs.

For instance, the pylon ducts in the Citation 680 use a red sealant. If you assume, based on the color, the sealant used is a typical RTV sealant, you would be wrong. In this circumstance, the maintenance manual calls for sealant SS-69A, with a maximum temperature of 330 degrees C.

If you apply the standard red RTV with a maximum operating temperature of only 260 degrees C, you run the risk of having high temperature bleed air leaks due to premature failure of the sealant in the engine pylon area.

I recommend that you consult the maintenance manual for the correct data regarding sealants.