Airworthy PrepFlight Instructor Airplane test code
AI.X.E.K4Slow flight, Stalls, and Spins: Accelerated Stalls
Flight Instructor Airplane test standard, area of operation X, task E
Written as ai.x.e.k4 or AI.X.E.K4 on your score report.
The FAA's wording
Factors leading to an accelerated stall and preventive actions.
What it means
AI.X.E.K4 is a knowledge element in the Slow flight, Stalls, and Spins area of operation of the Flight Instructor Airplane test standard. A knowledge element is something the FAA expects you to know, and the written test asks questions on it.
- AI
- Flight Instructor Airplane ACS
- X
- Area of operation X: Slow flight, Stalls, and Spins
- E
- Task E: Accelerated Stalls
- K4
- Knowledge element 4
Seeing it on your score report
Your Airman Knowledge Test Report lists a code for each area where you missed a question. Seeing AI.X.E.K4 there means at least one of your wrong answers was on this element. If you are taking the practical test next, expect the examiner to ask about it. Retaking the written? Start with this code and the others on your report.
Sources: FAA-S-ACS-25, Flight Instructor for Airplane Category ACS (November 2023, effective May 31, 2024); FAA Airman Knowledge Testing Matrix (revised 9/25/26), p. 2.
Can be printed on 2 tests
- Flight Instructor Airplane (Added Rating) (AFA)
- Flight Instructor Airplane (FIA)
Got more than one code on your report?
Paste them all into the free study planner and it groups them by subject, most missed first.