EU-OPS 1 - Extract — Page 12, Lesson 14

We're now moving into the regulatory side of mass and balance — this is EU-OPS 1, the actual European operating rules. This is the legal framework that turns all the physics and weighing theory into mandatory procedures. Let's work through it in order. First, we're in the middle of the rules on fleet values. A fleet value is a single standard mass and balance figure applied to a group of identical aeroplanes, instead of weighing each one individually. The rule here says: to add a new aeroplane to a fleet that's already operating on fleet values, the operator must verify — either by actually weighing it or by computation — that its real values fall within the tolerances specified in subparagraph 2(ii). So there's a defined tolerance band, and the new aircraft must sit inside it. Then there's a timing rule: to stay compliant with subparagraph 2(i), the fleet values must be updated at least at the end of each fleet mass evaluation. So the values aren't static — they get refreshed at the end of every evaluation cycle. Now the key part — how many aeroplanes must be weighed to establish or maintain fleet values. Let "n" be the number of aeroplanes in the fleet using fleet values. Between two fleet mass evaluations, the operator must weigh a minimum number, and that number depends on the fleet size. If the fleet has 2 or 3 aeroplanes, you must weigh all of them — the minimum is n. If the fleet has 4 to 9 aeroplanes, the minimum is (n + 3)/2. So for a fleet of 5, that's (5+3)/2 = 4 aeroplanes. If the fleet has 10 or more, the minimum is (n + 51)/10. For a fleet of 10, that's (10+51)/10 = 6.1, so you'd round up to 7. Notice the pattern — the larger the fleet, the smaller the proportion you must weigh. There's also a selection rule: when choosing which aeroplanes to weigh, you must pick those that have not been weighed for the longest time. That keeps the data fresh across the whole fleet. And the interval between two fleet mass evaluations must not exceed 48 months — that's four years, the maximum cycle. Now the weighing procedure itself. The weighing must be done either by the manufacturer or by an approved maintenance organisation — so it's not something just anyone can do. Then there are normal precautions, consistent with good practice. Four are listed. First, checking for completeness of the aeroplane and equipment — nothing missing, nothing extra. Second, determining that fluids are properly accounted for — fuel, oil, hydraulic fluid, water, all must be in a known state. Third, ensuring the aeroplane is clean — dirt and debris add mass and shift the balance. Fourth, ensuring the weighing is accomplished in an enclosed building — so wind and weather don't affect the scales. Then the equipment requirements. Any weighing equipment must be properly calibrated, zeroed, and used in accordance with the manufacturer's instructions. Each scale must be calibrated — either by the manufacturer, by a civil department of weights and measures, or by an appropriately authorised organisation — within two years, or within a time period defined by the manufacturer of the weighing equipment, whichever is less. So the calibration interval is the shorter of two years or the manufacturer's specified period. And the equipment must enable the mass of the aeroplane to be established accurately — that's the whole point. Then we shift to special standard masses for the traffic load. We already have standard masses for passengers and checked baggage. This rule says an operator can also submit, for approval by the Authority, standard masses for other load items. So the regulator can approve standard figures for cargo, or other items, beyond just people and bags. Finally, aeroplane loading — three requirements. First, the operator must ensure loading is performed under the supervision of qualified personnel. Second, the loading of freight must be consistent with the data used for the calculation of the aeroplane's mass and balance — meaning the actual load must match what was assumed in the paperwork. Third, the operator must comply with additional structural limits — and here they list them: floor strength limitations, the maximum load per running metre, the maximum mass per cargo compartment, and/or the maximum seating limits. These are separate from the basic mass and balance envelope — they protect the structure itself. So the whole picture: fleet values let you avoid weighing every aircraft, but there's a strict sampling schedule, a 48-month evaluation cycle, a rigorous weighing procedure with calibration limits, and then loading rules that tie the physical load to the calculated figures and protect structural limits. That's the regulatory backbone of mass and balance under EU-OPS 1.