Any CG position within the envelope is legal — but effects differ noticeably.
Comparison
| Property | Forward CG | Aft CG |
|---|---|---|
| Stall speed | Higher (elevator must produce more downforce) | Lower |
| Cruise speed | Lower (more trim drag) | Higher |
| Longitudinal stability | More stable — returns to original attitude after disturbance | Less stable |
| Elevator forces | Heavier | Lighter |
| Stall/spin behaviour | Clear "nose bobble" at stall, easier recovery | Worse spin tendency, harder recovery — too aft = unrecoverable spin |
| Landing performance | Longer roll (elevator must pull harder to flare) | Shorter roll |
| Take-off performance | Slightly longer | Slightly shorter |
| Climb gradient | Slightly worse | Slightly better |
Safety perspective
| Risk | Forward limit | Aft limit |
|---|---|---|
| Insufficient elevator authority | At rotation or flare | (not relevant) |
| Unrecoverable stall/spin | (rare — only if AFM permits) | critical risk |
| Structural overload | (same) | (same) |
| Pitch-up tendency | (low) | high — pilot must actively keep nose down |
Operational example
- Two-seat trainer with pilot only and full fuel: often forward CG → higher stall speed; watch hard landings.
- Two rear passengers and heavy bag: often aft CG → lighter controls; be careful in slow flight and on landing.