Monty,
Welcome to retirement and part time work. Federal law requires anyone operating a commercial motor vehicle (CMV) in interstate commerce to possess a medical certificate. Commercial Driver License requirements contained in Title 49, Code of Federal Regulations (49 CFR), 383 do not cover medical requirements.
FMCSA utilizes the definition of CMV contained in 49 CFR, 390.5 for medical card requirements. Therefore, if you are operating a CMV with a gross vehicle weight rating (GVWR) or a combination with a Gross Combination Weight Rating (GCWR) of 10,001 pounds or more, you are required to possess a medical certificate [49 CFR 391.11(b)(4)].
You would have to operate the 26,000 GVWR straight truck in intrastate commerce to avoid medical certificate requirements, including not being required to possess specified endorsements.
Additionally, there is no such animal as an "air brake" endorsement, only "air brake" restrictions, usually administered when a person fails the air brake portion of the written test or the drive test is taken with a vehicle that does not have air brakes. Good Luck.
Sgt. Pete Camm (Ret.)
California Highway Patrol
Ol’ Blue, USA
P.O. Box 4444
Van Nuys, CA 91412-4444
