A load sheet is the balance calculation with a signature line: the standard form on which a specific flight's loading is assembled, totalled, checked against every limit and certified fit to fly. This lesson works the light-aeroplane version end to end, the same one the exam's sample single-engine aeroplane uses: build the masses row by row, carry the moments beside them, find the CG at zero fuel and at take-off, prove both inside the envelope, and absorb the late bag that arrives after the arithmetic was finished.
What the two sheets are for
The load sheet — the mass ledger of one flight: it assembles the dry operating mass, traffic load and fuel into the zero fuel, ramp, take-off and landing masses, proves each against its limit from the mass-limits lesson, and carries the signatures that make the loading official. Its principle is the ladder of the terminology lesson turned into a form; its purpose is proof, before flight, that the aircraft is legal in mass.
The trim sheet — the balance ledger: it locates the CG of that same loading, by moments on a light aeroplane or by index entries on a large one, and proves it inside the permitted envelope at every stage of the flight. On big aircraft it also converts the answer into a stabiliser-trim setting for take-off, which is where its name comes from.
On a light aeroplane the two jobs usually share one page, called a loading manifest or balance schedule: a mass column and a moment column, added in parallel, with the CG falling out of one division at the bottom. On large aeroplanes the two halves grow into separate documents, the next two lessons' subject. The principle never changes; only the bookkeeping grows.
Working the balance schedule
The schedule is the arithmetic method of the previous lesson with the rows pre-printed in loading order: empty condition first, then the seats and baggage to zero fuel mass, then fuel to ramp mass, then the burns. Moments are usually carried divided by 100 to keep the column readable, a habit the sample sheets share, and every subtotal row is a checkpoint against a limit.