Question about air brake endorsement in Washington

[Anomalous]

If the bus is titled as an RV, the following site may be of interest: http://changingears.com/rv-sec-state-rv-license.shtml. It doesn't address air brakes, but it does show which states need special non-commercial licenses or endorsements for large vehicles or trailers.

[CAMO-MONSTER]

MY mom and dad both drive bus my mom has driven for 19 years and she told me if it is less than 15 pass and not commercial then you don't have to have the endorsement for the air brakes.