EU-OPS 1 - Extract — Page 12, Lesson 10

I want to walk you through the EU-OPS 1 regulations on mass and balance documentation. This is the legal backbone of everything we do before every single flight. Let's start with OPS 1.625, which is all about the paperwork. The rule says an operator must establish mass and balance documentation prior to each flight. That documentation specifies the load and its distribution. The whole point is that this document must enable the commander — that's you, the pilot in command — to determine that the load and its distribution are such that the mass and balance limits of the aeroplane are not exceeded. So the document isn't just a formality; it's the tool that lets you verify the aircraft is within its certified limits before you go. Now, there's a chain of responsibility here. The person who prepares the mass and balance documentation must be named on the document. Then, the person supervising the loading of the aeroplane must confirm by signature that the load and its distribution are in accordance with the documentation. So the loader signs to say the actual physical loading matches what's on the paper. Finally, the document must be acceptable to the commander, and your acceptance is indicated by countersignature or equivalent. So you sign it too, taking responsibility that you've checked it. There's also a cross-reference to OPS 1.1055 (a)12, which is another part of the regulations, but for now just know this documentation requirement ties into the broader operational rules. Next, paragraph (b) says an operator must specify procedures for last minute changes to the load. This is critical — if something changes right before departure, like a passenger is added or cargo is moved, there has to be a defined procedure to handle that, so the documentation stays accurate. And paragraph (c) gives some flexibility: subject to the approval of the Authority, an operator may use an alternative to the procedures required by paragraphs (a) and (b). So the regulator can approve a different method, but it has to be approved — you can't just make up your own system. Now let's move to Appendix 1 to OPS 1.605, which is about mass and balance in general. This section deals with how you determine the dry operating mass of an aeroplane. First, weighing. New aeroplanes are normally weighed at the factory, and they're eligible to be placed into operation without reweighing if the mass and balance records have been adjusted for any alterations or modifications. So if the aircraft is modified, the records must be updated to reflect that. There's also a rule about transfers between operators. If an aeroplane is transferred from one operator with an approved mass control programme to another operator with an approved programme, it need not be weighed prior to use by the receiving operator — unless more than four years have elapsed since the last weighing. So the four-year mark is the trigger. Then we have the periodic requirement. The individual mass and centre of gravity position — that's the CG, the point where the aircraft balances — of each aeroplane shall be re-established periodically. The maximum interval between two weighings must be defined by the operator, and it must meet the requirements of OPS 1.605 (b). So the operator sets the interval, but it has to comply with the regulation. In addition, the mass and the CG of each aeroplane shall be re-established either by weighing, or by calculation — but only if the operator can provide the necessary justification to prove the validity of the method of calculation chosen. And this re-establishment is triggered whenever the cumulative changes to the dry operating mass exceed ±0.5% of the maximum landing mass, or the cumulative change in CG position exceeds 0.5% of the mean aerodynamic chord. The mean aerodynamic chord is the average chord of the wing, and it's the reference for CG position. So those are the two thresholds: half a percent of maximum landing mass for weight, and half a percent of the mean aerodynamic chord for CG position. Finally, there's the fleet mass and CG position concept. For a fleet or group of aeroplanes of the same model and configuration, an average dry operating mass and CG position may be used as the fleet mass and CG position — provided that the dry operating masses and CG positions of the individual aeroplanes meet the tolerances specified in subparagraph (ii). And the criteria in subparagraphs (iii), (iv), and (a)3 also apply. So instead of weighing every single aircraft, you can use an average for the fleet, but only if the individual aircraft stay within the allowed tolerances. That's where the excerpt ends — we're just at the start of the tolerance details in subparagraph (ii). But you've got the core structure now: the documentation chain of responsibility, the weighing rules, the four-year transfer rule, the 0.5% thresholds, and the fleet averaging concept.