Let's take them in order — Page 1, Lesson 5

I want to walk you through the regulatory heart of mass and balance — the EU-OPS 1 Subpart J extract. This is the rulebook text that governs how an operator must handle loading, mass, and balance, and it's structured as a series of numbered paragraphs, OPS 1.610, OPS 1.615, OPS 1.620, and so on. Let's take them in order. First, OPS 1.610, titled "Loading, mass and balance." This paragraph sets the fundamental obligation: an operator shall specify, in the Operations Manual, the principles and methods involved in the loading and in the mass and balance system. And that system must meet the requirements of OPS 1.605 — which is the preceding rule that lays down the overall requirement for a mass and balance system. So 1.610 is telling you that whatever system you build, it has to satisfy 1.605, and the details of how you load and how you compute mass and balance must be written down in the Operations Manual. Crucially, this system must cover all types of intended operations. That's a completeness requirement — every kind of flight you plan to do has to be covered by the documented system. Now OPS 1.615, "Mass values for crew." This is about what mass values you use to determine the dry operating mass. Let me define that term clearly: dry operating mass is the mass of the aeroplane ready for service but without traffic load — no passengers, no cargo, no baggage — and it includes the crew, their baggage, and everything needed for the flight except the payload and fuel. The rule gives you three options for crew mass values. Option one: actual masses, including any crew baggage — you weigh the actual crew members. Option two: standard masses, including hand baggage, of 85 kg for flight crew members and 75 kg for cabin crew members. So a pilot counts as 85 kilograms, a cabin crew member as 75, and that figure already includes their hand baggage. Option three: other standard masses acceptable to the Authority — meaning the national aviation authority can approve a different standard value if the operator justifies it. Then paragraph (b) of 1.615: the operator must correct the dry operating mass to account for any additional baggage. So if a crew member carries more than the hand baggage included in the standard figure, that extra mass has to be added. And here's the balance part — the position of this additional baggage must be accounted for when establishing the centre of gravity of the aeroplane. So it's not just about the total mass; where that baggage sits in the aeroplane shifts the centre of gravity, and you must account for that position. Now OPS 1.620, "Mass values for passengers and baggage." This is a longer one. Paragraph (a) says the operator shall compute the mass of passengers and checked baggage using either the actual weighed mass of each person and the actual weighed mass of baggage, or the standard mass values specified in Tables 1 to 3 — which are referenced but not reproduced in this extract. So you have two basic methods: weigh everyone and everything, or use the standard values from those tables. But there's an important exception. Where the number of passenger seats available is less than 10, passenger mass may be established by use of a verbal statement by, or on behalf of, each passenger, and adding to it a predetermined constant to account for hand baggage and clothing. So on a small aeroplane with fewer than ten seats, you can ask each passenger their mass, or have someone state it on their behalf, and then you add a fixed constant — a predetermined value — to cover hand baggage and clothing. That's a third method, and it's only permitted in that small-aircraft case. And the rule closes with a procedural requirement: the procedure specifying when to select actual or standard masses, and the procedure to be followed when using verbal statements, must be included in the Operations Manual. So the operator can't just decide on the fly — the decision logic and the verbal-statement procedure have to be documented. Finally, paragraph (b) of 1.620: if determining the actual mass by weighing, the operator must ensure that passengers' personal belongings and hand baggage are included. And such weighing must be conducted immediately prior to boarding and at an adjacent location. So the weighing has to happen right before boarding, at a scale next to the boarding point, and the passenger must be weighed with their personal belongings and hand baggage on them — otherwise the figure wouldn't represent the true mass they bring aboard. Let me tie this together. The whole extract is about one thing: the regulatory framework for how you establish the mass and balance of the aeroplane before every flight. You have a documented system in the Operations Manual, you have defined mass values for crew — actual, standard, or authority-approved — and for passengers and baggage you have actual weighing, standard tables, or the small-aircraft verbal statement method. And every method has its correction and its documentation requirement, because mass and balance isn't just about total weight — it's about where that weight sits, which drives the centre of gravity. That's the professional core of this chapter.