Definition
A symbol used in weight-shift calculations representing a rearward (aft) shift in the center of gravity (CG) of three inches. The minus sign indicates direction (aft of the original CG location), and the numeral indicates the magnitude of the shift in inches.
Plain English
This is shorthand for 'the center of gravity moved 3 inches toward the tail.' The minus sign means the shift is rearward, and the 3 is how many inches it moved.
Context Anchor
Seen in weight-and-balance calculations when baggage, passengers, or equipment are moved to a different station in the aircraft.
Derivation
CG stands for 'center of gravity.' In weight-shift problems, a minus sign is used by convention to indicate a rearward (aft) shift, while a plus sign indicates a forward shift. The number is simply the distance in inches.
Why Pilots Care
Even a small unaccounted CG shift can push the aircraft outside its approved operating envelope, affecting stability and control.
Analogy
Think of balancing a ruler on your finger. If you slide a small weight along the ruler, the balance point moves. –³CG is the amount that balance point moved.
Intuition Check
Do not read –³CG as “negative cubed CG.” In this FAA weight-shifting context, it means the change in CG location.
Example Sentence 1
After moving the baggage from the forward compartment to the aft compartment, the pilot calculated a –3 CG shift, meaning the center of gravity moved three inches rearward.
Example Sentence 2
The pilot recalculated the new CG after shifting two passengers forward to correct the aft limit exceedance.