Aviation Logistics Knowledge Lecture – Calculating ULD Occupation According to Cargo Size

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Aviation Logistics Knowledge Lecture – Calculating ULD Occupation According to Cargo Size

Hello everyone, after a round of silence, I am here again. Before, because of some things at home, I didn’t have time to update for the time being.


Today we continue to discuss the knowledge of air freight. This time I want to talk about how to calculate how many boards are needed after I get the size of the goods.


This knowledge point is very practical, but it is not a panacea. why? As I said before, all the places where there may be problems appear in the cargo station (taught by my former boss). How will this truth be reflected in practical work? To put it simply, even if we have calculated the board position in advance, there will still be many places that do not match our calculation during the actual board play process. Therefore, after we have calculated, we cannot say that the plan must be followed in order to play the board. Because plans can’t change quickly. We always need to analyze the problem according to the actual situation.


Well, before we start, let’s get ready. For those who are just starting to calculate the board position, some tools are needed, such as: calculator, pen, paper, ruler, etc. For those who are familiar with it, seeing the size, you can already think of the way to play the item in your mind (I haven’t gotten to this point yet). Also, it is imperative to be familiar with the size of each ULD ( click here to review common ULD sizes ).


Below, we explain the most common tray size: 120x80x100cm. We often see this size. Such a tray is best equipped with LD ( click here to see what LD means ). In this size, 5 can be installed without the height, and 6 can be installed when the height is 10cm. You can put 10 pieces in a height of 10cm (although I have seen 10 pieces, but it is strongly not recommended for everyone to put 10 pieces, because it is too dangerous). This size should be memorized by our hearts and need not be calculated any more. But now I will tell you how to calculate it.


First of all, we know that the size of a PMC is 244x318cm. The height of an LD PMC is at most 160cm. This is, you can take out paper and pen and draw a rectangle to represent a PMC. Its short side is 244cm and its long side is 318cm. The picture below is drawn by me and is for reference only.

PMC size

PMC Size (Emm…I drew this myself)

As shown in the figure, we have drawn a piece of PMC, and then we need to put the size just now into this PMC. Try putting 120 on the short side first, then, you should be able to put 2 pieces. How many pieces can be put on the long side? We take out the calculator, divide 318 by 80, we can know that there are at most 3 pieces on the long side. So, this PMC can hold 6 pieces, right? The calculation is like this, but as I said at the beginning, there is a difference between calculation and actual. What’s the difference here? We forgot to count the position of the edge of the board to the buckle. Every ULD will have a plate buckle. Taking PMC as an example, I have measured that the position from the edge of the plate to the plate buckle is about 7cm. Therefore, if we put two pieces of 120 on the short side, it will actually press the plate buckle. So this plan doesn’t work. In the case of not raising the height, a PMC can only hold five such goods. Specifically, it is put like this.

I also drew this myself

I also drew this myself


Therefore, at this time, the length of the goods on the long side of the ULD is 80+120+80=280, and the length of the goods on the short side of the ULD is 120+80=200. In this way, both the long side and the short side are full. Can’t let it go anymore.


I also remind everyone that when calculating the board position, you need to be flexible. You see, the long and short sides of the goods here are placed at intervals, and it is not necessary to place all of the same size on one side.


The above is the case of no padding. If the padding is 10cm higher, then one more piece can be installed. why? As we said just now, if two pieces of 120 pieces of goods are placed on the short side, the plate buckle will be pressed, how can it not be pressed? The simplest and crudest method is to raise the cargo. Of course, it can be raised with pallets, or it can be raised with cargo. If you use the goods to elevate, you must pay attention to the goods below must be able to bear the load, otherwise, the goods below will be crushed and the goods will be damaged.

No surprise, I drew this as well...

No surprise, I drew this as well…


The picture above shows the situation where six pieces of goods are placed after the height is raised. Okay, I admit I drew the scales wrong, but that’s what it means. At this time, the length of the goods on the short side of ULD: 120+120=240. And the length of the goods on the long side of ULD: 80+80+80=240cm. Therefore, neither side exceeds the length of the PMC, but it will press the plate buckle, so In such cases, you need to raise the cargo to fight.


Next, let’s look at the impact of changes in the height of the cargo on the board. The height of the cargo just now is 100cm, then after the height is raised, the total height is 110cm. For the height limit of an LD, there are still some leftovers. If the height of the cargo itself is 120cm, it will be 130cm after padding. This height has no effect on the number of pieces of the board, but if it will exceed 160cm once it is raised, then it can’t be boarded like this. In addition, after the pallet is finished, you can actually put some cartons on the pallet, but the height of the carton should be controlled. The same can not exceed 160cm.


The same is true for other various cargo sizes, just calculate how many pieces a board can hold. Once again, I would like to remind you that when calculating, your brain needs to be turned at a high speed. Ban Wang is not practiced in a day.


Alright, that’s it for today’s issue. See you next time.

NB: Karron is the owner of the “NatureCalls” Wechat Official Account.

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