FAA Flight Instructor Airplane (FIA)Performance, Weight and BalanceEasy
An instructor loads a training airplane with its CG near the forward limit for a lesson on slow flight. Compared to loading at the aft CG limit, this forward loading will result in:
- AA higher stall speed and increased elevator control force required during flare
- BReduced longitudinal stability and a tendency to porpoise on landing
- CAn increased tendency toward an uncommanded nose-up pitch at low airspeed
- DA lower stall speed and lighter elevator control forces
Show answer & explanationAnswer & explanation
Correct answer: A. A higher stall speed and increased elevator control force required during flare
A forward CG increases the download the horizontal stabilizer must produce to balance the airplane, which increases effective wing loading, raises stall speed slightly, and requires more elevator (up) force to flare because the elevator has less leverage to rotate the nose up.
Why the other options are wrong
- B. Forward CG increases longitudinal stability, the opposite of this statement.
- C. Forward CG actually makes the airplane more nose-heavy, not nose-up prone.
- D. Forward CG increases, not decreases, stall speed and control forces.
Forward CG Effects
Loading the CG toward the forward limit increases stability but raises stall speed and elevator control forces needed to flare or round out.
- Forward CG increases stability (more resistant to pitch upsets)
- Raises stall speed slightly due to increased tail download
- Requires more back-elevator force to flare for landing
Memory trick: Forward = Firm and Fast (stall speed up)