Definition
The rearmost allowable position of an aircraft's center of gravity (CG), as specified by the manufacturer in the weight and balance data. Loading the aircraft so the CG falls behind this point is prohibited because it produces unsafe handling characteristics, including reduced longitudinal stability and degraded stall recovery.
Plain English
The furthest-back point where the aircraft's balance point is still allowed to be. If the balance point ends up behind this line, the aircraft is loaded incorrectly and is not safe to fly.
Context Anchor
Seen in aircraft weight-and-balance information, loading charts, and maintenance or preflight loading calculations.
Derivation
Aft' is a nautical term meaning 'toward the rear of a vessel,' carried over into aviation to mean 'toward the tail.' 'Aft-most' simply means 'furthest aft' — the rearmost point. Knowing 'aft' always points to the tail makes the limit easy to picture.
Why Pilots Care
Exceeding the aft-most limit reduces longitudinal stability and can produce an uncontrollable nose-up pitch tendency.
Intuition Check
Aft-most does not mean the very back of the airplane. Here it means the rearmost allowed position of the aircraft’s balance point; farther back than that is outside the approved loading range.
Example Sentence 1
After adding two passengers in the rear seats and bags in the aft baggage area, the technician recalculated the CG and confirmed it was still forward of the aft-most limit.
Example Sentence 2
The aft-most limit for this model is listed at 42 percent mean aerodynamic chord in the weight and balance data.