EU-OPS 1 - Extract 1 — Page 17, Lesson 20

I want to walk you through the regulatory heart of mass and balance — this is Appendix 1 to OPS 1.625, which is the EU-OPS rule that tells an operator exactly what must go into the mass and balance documentation for every flight. This is the document that proves the aeroplane is loaded legally and within its certified limits before it departs. Let's start with the contents. The regulation lists twelve mandatory items, lettered (A) through (L). I'll take them in order. (A) is the aeroplane registration and type — that's the aircraft's identity, its tail number and its model. (B) is the flight identification number and date — so you know which flight and which day this document belongs to. (C) is the identity of the commander — the pilot in command, the person ultimately responsible for the flight. (D) is the identity of the person who prepared the document — the one who actually did the mass and balance calculation. Notice the regulation deliberately separates these two: the person who prepares it, and the commander who accepts it. (E) is the dry operating mass and the corresponding CG of the aeroplane. Dry operating mass is the basic aeroplane plus crew, catering, and all the items needed for the flight but excluding fuel and payload. CG is the centre of gravity — the point where the aeroplane would balance. So this item fixes where the empty-but-ready aeroplane sits. (F) is the mass of the fuel at take-off and the mass of trip fuel. Trip fuel is what you expect to burn to reach your destination. The take-off fuel is what's actually in the tanks at the moment of departure. (G) is the mass of consumables other than fuel — things like oil, water, or galley supplies that get used up during the flight. (H) is the components of the load, including passengers, baggage, freight and ballast. Ballast is weight added deliberately, usually in the cargo hold, to bring the CG into an acceptable position. (I) is the take-off mass, landing mass and zero fuel mass. Zero fuel mass is the total mass of the aeroplane and its payload, but excluding all fuel — this matters because the wing structure is stressed with the fuel excluded. (J) is the load distribution — how that payload is spread through the aeroplane, which directly drives the CG position. (K) is the applicable aeroplane CG positions — the actual centre of gravity values for this particular loading. And (L) is the limiting mass and CG values — the certified maximums and the forward and aft CG limits that must not be exceeded. Now, there's a flexibility clause. Subject to the approval of the Authority — that's the national aviation authority — an operator may omit some of this data from the documentation. So the twelve items are the full requirement, but the Authority can allow a reduced set. Next we come to the last minute change. This is a very practical rule. If any last minute change occurs after the mass and balance documentation has been completed, that change must be brought to the attention of the commander, and it must be entered on the documentation. But there's a limit built in: the maximum allowed change in the number of passengers or hold load that can be accepted as a last minute change must be specified in the Operations Manual. And here's the critical threshold — if that number is exceeded, new mass and balance documentation must be prepared. So a small tweak gets recorded on the existing sheet; a big change forces a complete recalculation. Then we move to computerised systems. Where the documentation is generated by a computerised mass and balance system, the operator must verify the integrity of the output data. He must establish a system to check that amendments of his input data are incorporated properly in the system, and that the system is operating correctly on a continuous basis. And there's a hard interval: this verification must be done by checking the output data at intervals not exceeding 6 months. So every six months at most, you prove the computer is still doing the sums correctly. Next, onboard mass and balance systems. If an operator wants to use an onboard mass and balance computer system as a primary source for despatch — meaning the aeroplane's own system is the authority for releasing the flight — he must obtain the approval of the Authority first. It's not automatic; it needs explicit permission. Finally, datalink. When the mass and balance documentation is sent to aeroplanes via datalink, a copy of the final mass and balance documentation as accepted by the commander must be available on the ground. So even though the commander accepts the document electronically in the cockpit, there must be a ground copy retained — that's your audit trail. Let me tie this together. The whole point of this appendix is accountability. You have a document that names the aircraft, the flight, the commander, and the preparer; it states every mass and every CG position; it lists the limits; and it has a clear chain of custody — the preparer computes, the commander accepts, and any change is either recorded or triggers a full re-preparation. And whether the system is paper, computerised, onboard, or datalink, the regulation keeps the Authority in the loop and keeps a verifiable record on the ground. That's the legal skeleton of every mass and balance sheet you'll ever sign as a professional pilot.