If you fail any FAA written test (receive a score below 70%), you can retake the test, but first, you will have to: Pay the retest fee (usually $165) Receive ground instruction from a Certified Instructor and have them give you a written "endorsement" stating you are prepared to retake the test. Keep your failed knowledge test results sheet to show at the testing center when you go for your retake. But hey, you can always make things simple and sign up for our Written Prep Bootcamp Course here.  We guarantee you will pass on your first try, or we'll pay for your test PLUS $175.