FAA Flight Instructor Airplane (FIA)Performance, Weight and BalanceEasy
An instructor loads a training airplane with its CG near the aft limit before a lesson on stall and spin awareness. Compared to a forward CG loading, this aft CG condition will most likely
- Adecrease the airplane's stall speed and make stall/spin recovery more difficult
- Bincrease the airplane's stall speed and improve controllability during recovery
- Cincrease static longitudinal stability and require more forward stick force to raise the nose
- Dhave no effect on stall speed but shorten the time required for spin recovery
Show answer & explanationAnswer & explanation
Correct answer: A. decrease the airplane's stall speed and make stall/spin recovery more difficult
An aft CG reduces the download the tail must produce, which slightly lowers stall speed but also reduces the elevator's effectiveness for pitch and spin recovery, making the airplane less stable and harder to recover.
Why the other options are wrong
- B. Stall speed decreases, not increases, with aft CG.
- C. Aft CG decreases, not increases, static longitudinal stability.
- D. Aft CG lengthens, not shortens, spin recovery time due to reduced elevator authority.
Aft CG Effects
Loading an airplane near its aft CG limit reduces longitudinal stability, lowers stall speed slightly, and makes stall/spin recovery more difficult.
- Aft CG = less tail download needed = lower stall speed
- Aft CG reduces static stability
- Aft CG makes stall/spin recovery harder due to less elevator authority
Memory trick: Aft = A Floppy Tail (less control, less stability)