The F Endorsement Is for Drivers Who Operate Vehicles with Air Brakes
The F endorsement on a Tennessee driver's license means you have passed the knowledge and skills tests required to operate a commercial vehicle equipped with an air brake system. Without this endorsement, you cannot legally drive any commercial vehicle that uses air brakes, even if you hold a valid CDL in another class.
Air brakes work differently from the hydraulic brakes on most passenger cars. They use compressed air to explore stopping force, and they require specific knowledge about how to inspect them, maintain proper air pressure, and respond if the system fails. Tennessee's Department of Safety and Homeland Security requires drivers to demonstrate this knowledge before issuing the endorsement.
If the vehicle you drive has air brakes and you do not have an F endorsement, you are operating illegally. Your employer cannot assign you to such a vehicle, and law enforcement can cite you during a roadside inspection.
Key Takeaways
- The F endorsement certifies that you can safely operate commercial vehicles with air brake systems.
- You must pass both a written test about air brake operation and a practical skills test to receive the F endorsement.
- The endorsement appears on your CDL card and is required by law if your assigned vehicle has air brakes.
- If your vehicle has air brakes and you lack the F endorsement, you cannot legally drive it for commercial purposes.
- You can add the F endorsement to an existing CDL or obtain it when you first explore for your commercial license.
How to Get the F Endorsement in Tennessee
To add an F endorsement to your Tennessee CDL, you must pass two separate tests: the air brakes knowledge test and the air brakes skills test. Both are administered by the Tennessee Department of Safety and Homeland Security at their testing locations.
The air brakes knowledge test covers how air brake systems work, how to inspect them before driving, how to recognize warning signs of failure, and how to respond in emergency situations. You study from the Tennessee CDL Manual, which is free and available online. Most people spend 5 to 10 hours studying this section before testing.
The air brakes skills test takes place in a commercial vehicle equipped with air brakes. An examiner watches you perform a pre-trip inspection specific to air brakes, then observes your ability to operate the vehicle safely. This test typically lasts 30 to 45 minutes and covers braking techniques, stopping distance, and handling the vehicle under various road conditions.
You can schedule both tests at any Tennessee CDL testing location. Some locations allow you to test on the same day; others require separate appointments. Call ahead to confirm their schedule and whether they have an air brake vehicle available for the skills test.
When You Need the F Endorsement
You need the F endorsement if your job requires you to drive any commercial vehicle with an air brake system. This includes most large trucks (Class 8 trucks), many buses, and some medium-duty commercial vehicles. If you are unsure whether your assigned vehicle has air brakes, ask your dispatcher or safety manager—they can tell you when ready.
Some commercial vehicles have hydraulic brakes only, which do not require the F endorsement. Smaller delivery trucks, some box trucks, and certain specialized vehicles may fall into this category. Your employer should clarify this before you are assigned to a vehicle.
If you already hold a CDL without the F endorsement and your employer assigns you to a vehicle with air brakes, you must obtain the endorsement before you can legally operate that vehicle. You cannot drive it even once without the endorsement, and doing so can result in a citation and fines.
The Air Brakes Knowledge Test
The Tennessee air brakes knowledge test contains 25 questions, and you must answer at least 20 correctly to pass. The test covers five main topics: how air brake systems work, pre-trip inspection procedures, driving techniques with air brakes, emergency procedures, and maintenance awareness.
Common test questions ask you to identify components of an air brake system, explain what to do if air pressure drops below a safe level, describe the correct way to brake on a downhill grade, and recognize warning lights and gauges on the dashboard. You are allowed to take notes during your study period, but not during the test itself.
The test is offered in English and Spanish. You can retake it if you do not pass, though you may have to wait a few days before scheduling another attempt. Check with your local testing location for their specific retake policy.
The Air Brakes Skills Test
The skills test has three parts: the pre-trip inspection, the basic vehicle control test, and the road test. An examiner scores each part separately, and you must pass all three to earn the F endorsement.
During the pre-trip inspection, you walk around and under the vehicle while explaining to the examiner what you are checking and why. You must identify air brake components, test the brake pedal, check air pressure gauges, and demonstrate that you know how to spot problems. This portion typically lasts 10 to 15 minutes.
The basic vehicle control test takes place in a closed course or parking lot. You perform maneuvers such as straight-line backing, offset backing, and alley docking while the examiner watches for smooth, controlled movements and proper use of the air brake system.
The road test lasts 20 to 30 minutes and includes city driving, highway driving, and various traffic situations. The examiner observes how you brake, accelerate, turn, and respond to traffic. You must demonstrate smooth braking without locking the wheels and proper control of the vehicle at different speeds.
Cost and Timeline for the F Endorsement
Tennessee charges a fee for each CDL test you take. The knowledge test and skills test are separate transactions, so you pay for each one. Fees vary slightly by testing location, but generally range from $10 to $25 per test. Some locations may charge a combined fee if you test on the same day.
The timeline depends on your testing location's availability. If you schedule both tests on the same day, you could have your F endorsement within a few hours of passing. If you schedule them separately, allow at least a few days between the knowledge test and the skills test to study and prepare.
Once you pass both tests, the examiner submits your results to the Tennessee Department of Safety and Homeland Security. Your new CDL with the F endorsement is typically mailed to you within 7 to 10 business days. In the meantime, you receive a temporary paper permit that you can use to drive vehicles with air brakes.
Renewing or Removing the F Endorsement
The F endorsement stays on your CDL for as long as your license is valid. You do not need to renew it separately or retake the test unless your CDL expires and you renew it. When you renew your CDL, Tennessee does not require you to retake the air brakes test—the endorsement carries forward automatically.
If you no longer need the F endorsement because you have changed jobs or no longer drive vehicles with air brakes, you can request to have it removed. Contact your local Tennessee Department of Safety and Homeland Security office to request a CDL modification. There is typically no fee to remove an endorsement.
Frequently Asked Questions
Can I get the F endorsement if I have never driven a commercial vehicle before?
Yes. You do not need prior commercial driving experience to obtain the F endorsement. You must hold a valid CDL in the appropriate class for the vehicle you will drive, but the air brakes endorsement itself has no experience requirement. You study the manual and pass the tests just like anyone else.
What happens if I fail the air brakes knowledge test?
You can retake it after a waiting period, which varies by testing location. Most locations allow you to retake the test within a few days. You pay the test fee again each time you retake it. There is no limit to how many times you can retake the test.
Do I need the F endorsement if my vehicle has both air brakes and hydraulic brakes?
Yes. If the vehicle has an air brake system for any wheels—even if it also has hydraulic brakes on other wheels—you must have the F endorsement. The presence of air brakes anywhere on the vehicle triggers the requirement.
Can my employer pay for the F endorsement test?
Yes. Many employers cover the cost of CDL tests and endorsements for their drivers. Ask your employer or recruiter whether they reimburse test fees or pay them directly to the testing location. Some companies require you to work for them for a certain period before they cover the cost.
What if I pass the knowledge test but fail the skills test?
Your knowledge test score remains valid, and you do not have to retake it. You only need to retake the skills test. Schedule another appointment with the testing location and practice the maneuvers and road techniques before your next attempt.