Aircraft Center of Gravity
Compute the center-of-gravity (CG) position of an aircraft with two weight stations, CG = (W₁·a₁ + W₂·a₂)/(W₁ + W₂), the total moment divided by the total weight, measured from a reference datum. The CG must stay within a safe envelope: too far forward the aircraft is nose-heavy and hard to rotate; too far aft, unstable. It is an essential part of the weight-and-balance check before each flight. Enter the weights and arms of the two stations.
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Aircraft center of gravity
Before every flight, the center of gravity (CG) of the loaded aircraft is worked out — one of the most safety-critical items in the whole preparation. With two weight stations (say, cabin and baggage compartment), CG = (P₁·b₁ + P₂·b₂)/(P₁ + P₂): the sum of the moments (weight × arm measured from a reference datum) divided by the total weight. The CG has to fall inside an approved envelope. Too far forward, the aircraft becomes 'nose heavy', demands more elevator authority and may fail to rotate on takeoff; too far aft, it turns unstable and can enter a stall or spin from which recovery is impossible. Payload shifts and fuel burn move the CG during the flight, so the check covers takeoff and landing conditions alike. Enter the weights and the arms of the two stations.
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