We open with the Introduction, then go straight into Limitations — Page 27, Lesson 34

This is the start of Chapter 2, "Definitions and Calculations," in your Mass and Balance book. This is where the entire subject comes together, so I want to give you the roadmap of what we're about to cover, because the structure itself tells you what matters. We open with the Introduction, then go straight into Limitations. That's the first big idea: an aeroplane has hard limits on how much it can weigh and where its centre of gravity can sit. We then look at the Effects of Overloading — what happens if you exceed the maximum mass — and the Effects of Out of Limit CG Position — what happens if the centre of gravity sits outside its allowed range. Both are dangerous, but in different ways, and we'll see exactly how. Then we cover the Movement of CG in Flight. The centre of gravity isn't fixed; it shifts as fuel burns off, as gear retracts, as flaps extend. You need to understand that movement to know whether you stay within limits throughout the whole flight, not just at take-off. Next, Some Effects of Increasing Aeroplane Mass. Heavier aircraft behave differently — longer take-off runs, reduced climb performance, higher stall speeds. We'll touch on those. Then we get into the core of the chapter: Definitions. This is the vocabulary you must master — terms like Basic Empty Mass, Maximum Take-off Mass, Zero Fuel Mass, and so on. Every one of these has a precise meaning, and the calculations all hang off them. After definitions, we move to Weighing of Aircraft and the Weighing Schedule — how the empty mass is actually established and recorded. Then the Minimum Equipment List, or MEL, which tells you what equipment may be inoperative and still allow dispatch. We then do the Calculation of Fuel Mass, because fuel is a big chunk of the mass and it has its own density considerations. Then we calculate the Basic Empty Mass and CG Position, and from there the Loaded Mass and CG Position for Light Aircraft. A key concept follows: CG Position as a Percentage of Mean Aerodynamic Chord (MAC). That's how we express the centre of gravity location on larger aircraft — as a percentage of the wing's mean chord, not just a distance from the datum. Then we handle Repositioning of the Centre of Gravity — both by Repositioning Mass and by Adding or Subtracting Mass. These are the techniques you use to bring an out-of-limit CG back into range. We then look at Graphical Presentation — the charts and envelopes used to do these calculations quickly. Then Cargo Handling, which brings in Floor Loading, Linear / Running Loads, and Area Load Limitations — the structural limits on how much weight a floor panel or a cargo bay can bear. Finally, we apply all of this to specific aircraft types: Single-engine Piston / Propeller Aircraft (SEP1), Light Twin Piston / Propeller Aircraft (MEP1), and the Medium Range Twin Jet (MRJT1). Each has its own loading procedures. We finish with the Calculation of the Loaded Mass and CG Position for Large Aircraft and Compiling a Document (Load Sheet) — the actual paperwork you produce for dispatch. So the whole chapter is a build: definitions, then limits, then how to calculate mass and CG, then how to fix an out-of-limit condition, then how to present it graphically, then how to apply it to real aircraft and produce the load sheet. We'll take it section by section. Let's start with the Introduction and Limitations.