The FAA Instrument Rating Airplane (IRA) knowledge exam consists of a test with 60 multiple choice questions drawing from a bank of hundreds of possible questions. The allotted time for the Instrument Rating Airplane knowledge exam is 2 and a half hours and the minimum passing score is 70. Acceptable forms of authorization for the Instrument Rating knowledge exam include:

Certificate of graduation or a statement of accomplishment certifying the satisfactory completion of the ground school portion of a course from an Federal Aviation Administration (FAA) certified pilot school.
Written statement from an FAA authorized ground or flight instructor showing satisfactory completion of the ground instruction required for the rating sought.
Certificate of graduation or a statement of accomplishment certifying the satisfactory completion of the ground school portion of a course from an agency such as a high school, college, adult education program, U.S. Armed Force, Reserve Officers Training Corp (ROTC) Flight Training School or Civil Air Patrol.
Written statement from an FAA authorized ground or flight instructor, certifying that they have personally reviewed the applicant's completion of a home study course and found the applicant has satisfactorily completed that course.
Logbook endorsement from an FAA authorized ground or flight instructor.

Passing score reports are valid for 24 calendar months. If the applicant has not completed his/her Instrument Rating Practical test before the expiration of the knowledge exam score report, then the applicant will need to re-take the Instrument Rating Airplane knowledge exam.

In the event that the applicant does not pass the Instrument Rating Airplane knowledge exam; the applicant is required to submit the failed score report indicating failure, along with an endorsement from an authorized instructor who gave the applicant the additional training, and certifying the applicant is competent to pass the test.