Learning ULDs the Easy Way | #219

ULDs (Unit Load Devices) are something you will inevitably encounter in the air cargo industry. At first glance, ULD codes like AKE, PMC, and PAG, consisting of three letters, look like magic spells. However, once you grasp the key points, you can 'decipher' them without relying on rote memorization. In this article, titled 'Learning ULDs the Easy Way,' I will outline three steps for beginners to understand them as quickly as possible.

Strategy Step 1: Think in 'Inches,' Not Millimeters

Since ULD standards originated in the United States, they are designed based on inches. While millimeter measurements often result in long, complex numbers, they convert into clean, whole numbers in inches.
88×125 inches (approx. 224×318 cm): PAG, etc.
96×125 inches (approx. 244×318 cm): PMC, etc.
60×61 inches (approx. 153×156 cm): AKE (LD3), etc.
The trick is simple: in professional practice, shorthand terms like '88' and '96' are common. Don't be afraid to discard millimeters entirely.

Strategy Step 2: Decipher the IATA 3-Letter Code

The meaning of each position in the 3-letter code is fixed.

1st Letter (Type): A = Certified Container / P = Certified Pallet
2nd Letter (Base Size): K = LD3 (60×61 in) / A = 88×125 in / M = 96×125 in
3rd Letter (Shape/Specification): E = Standard / C = Pallet with Net / N = Carrier-specific variation / W = Newly added container contour code (introduced in IATA ULDR 14th Edition 2026)

For example, 'AKE' can be read as A (Container) + K (LD3 size) + E (Standard). 'PMC' is P (Pallet) + M (96×125 in) + C (with net). If you master the second letter, you can guess the size even for codes you see for the first time.

Strategy Step 3: Master the 'Big Three' First

① AKE (LD3): Used in the lower deck of passenger aircraft like the B777 and A350. A box approximately 1.5m x 1.5m with one side slanted.
② PAG: 88×125 in pallet. Frequently used in medium-sized cargo aircraft and the lower decks of passenger aircraft.
③ PMC: 96×125 in pallet. The largest board for the main deck of large freighters like the B747F.

A Guide to Common Model Numbers in Practice

Beyond the big three, it is useful to understand other frequently used codes by category. In the LD3 family, there are derivatives of AKE such as AKN (carrier-specific) and AKW (LD3-45W) for the B787 and A330. Full-size container types include AAA/AAP (LD-9, 96×125 in, full-height, for B747/B777F main decks) and the half-height AMA, which is used for both the main and lower decks of the B747. For 88×125 in pallets, PAJ/PAP, the LD-11 series PLA, and the PGA/PGE/PGF (LD-26/LD-29) for the B747 lower cargo hold are also common.

In pharmaceutical transport, reefer containers such as Envirotainer's RKN/RAP, CSafe's APS, and Sonoco ThermoSafe's Pegasus are mainstream, and combinations with airlines that have obtained CEIV Pharma certification are becoming standard. For special specifications, AAF/AAX (automotive parts), HMA/HMJ (live animals/horses), and large pallets for the B777 main deck like Q7/Q6 also appear.

Practical Points

In the field, you will see these codes on AWB/House AWBs, ULD tags, and CFS warehouse loading lists. Checking the code is the first step in preventing accidents, as model numbers can differ slightly between airlines even for the same size (e.g., AKN vs. AKE), reefers require power connections and temperature log management, DG (dangerous goods) have loading restrictions, and AVI (live animals) have temperature and ventilation requirements. The official manual is the IATA ULD Regulations (ULDR) 14th Edition 2026, which added the new container contour code 'W' and model code 'AMW,' and established new life cycle assessment guidelines in Appendix J.
In the ULD pooling business, major players include Unilode (with over 200,000 units), Jettainer, and Nordisk, with Unilode also launching a lease service for lithium battery-compatible fire containment covers in 2026.

Applied Techniques for Memorization

'A_ _' means container
'P_ _' means pallet
The 2nd letter: K = LD3 small / A = 88 in / M = 96 in / B = 60 in rectangular.
The 3rd letter: E = standard / C = with net / F = special floor / N = carrier-specific.
If you have this reference table in your head, you can guess 80% of the model numbers you see for the first time.

Summary

Discard millimeters and think in inches (88/96). Identify the size by the second letter. Start with the big three: AKE/PAG/PMC. Just these three points will make air cargo ULDs surprisingly familiar.

Related notes: #161 ICAO / IATA basics, #155 Montreal Convention basics, #106 ULD basics

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