Definitions and Calculations — Page 63, Lesson 83

Let’s start with the single-engine piston/propeller aircraft, which the documentation calls SEP1. That’s the shorthand for Single-Engine Piston/Propeller aircraft. The procedure for compiling the load documentation for the SEP1, as given in CAP 696, is similar to the calculations we’ve already covered in these notes. But there’s one key difference you must notice: the load manifest and the CG envelope are specific to that particular type of aircraft. So you can’t just reuse a generic form; each aircraft type has its own manifest and its own centre-of-gravity envelope. There are examples in the question section starting at page 77. Now, the light twin piston/propeller aircraft, which we call MEP1 — that’s the Multi-Engine Piston/Propeller aircraft. Again, the procedure for compiling the documentation, given in CAP 696, is similar to the procedures we’ve defined in these notes. And again, the load manifest and CG envelope are specific to that type of aircraft. A sample calculation based on compiling the load sheet for that aircraft is shown in CAP 696, MEP1, page 2. CAP 696, MEP1, page 1 contains specific information based on the Mass & Balance requirements for that particular aircraft. So page 1 gives you the type-specific data, page 2 walks you through a sample load sheet calculation. You should study those pages, then attempt some self-assessment questions. Examples are in the question section starting on page 81. Now we move to the medium range twin jet, the MRJT1. This one has a more complex loading and trim sheet, which we’ll deal with shortly. CAP 696, MRJT1, pages 2 through 5 contain information specific to the MRJT1, and you should study those in detail. Notes on particular items follow. Let’s look at MRJT1 Figures 4.1 and 4.2, which deal with body stations. Here’s the core idea: it would be possible to locate components and parts of the airframe structure by actually measuring their distance from the CG datum. But that would be difficult and impractical on anything other than a very small aircraft. So instead, aircraft are divided about their three axes by a system — and that’s where we’ll pick up next.