Weight and balance is the calculation confirming an aircraft's total mass and centre of gravity are within certified limits for the flight. It is a legal pre-flight requirement, and in training aircraft with full fuel and two adults, limits are tighter than many students expect.
Weight and balance (mass and balance) is the pre-flight calculation confirming that an aircraft's total mass is within its certified limits and that its centre of gravity falls inside the approved envelope for every phase of the flight. Inputs are the aircraft's empty weight and moment (from the current weighing report), plus occupants, baggage and fuel — including the CG shift as fuel burns.
It is a legal requirement, not an estimate: the calculation must use the individual aircraft's actual empty-weight data, which changes with every modification and repaint — which is why the weighing report's currency matters as much as the arithmetic. In two-seat trainers with full fuel and two adults, the answer is frequently closer to the limit than students expect.
Why it matters for flight schools
W&B failures are a persistent accident factor in training and rental flying — an aft-CG aircraft that won't recover from the very stall being practised is the textbook case. For schools, the organisational duties are keeping every aircraft's weighing data current and accessible, teaching the calculation as habit rather than checkride theatre, and making dispatch verify it for edge cases: heavy students, baggage, full-fuel cross-countries. An out-of-envelope departure is a violation even if nothing happens.
How FlightLogger handles it
FlightLogger keeps each aircraft's current weight and moment data attached to the aircraft record, so pilots calculate from live data at booking — not from a photocopied sheet of the previous configuration.
Frequently asked questions
How often must an aircraft be weighed?
Whenever modifications or repairs change its empty weight or CG beyond documented calculation, and otherwise per the operator's programme — commonly every few years for commercial fleets. The current weighing report is part of the aircraft's required documentation.
Can two adults with full fuel exceed limits in a typical trainer?
Easily — many two-seat trainers cannot carry full tanks with two average adults. This is why schools set fuel-load standards per mission profile and teach students to compute rather than assume.