Section 4.3 Numerical Cross-Reference & the End-to-End Lookup Workflow

Section 4.3 Numerical Cross-Reference & the End-to-End Lookup Workflow

The IATA DGR certification exam is open book. That format changes what is being assessed: not whether you can recall a limit, but whether you can find the right limit, in the right column, in a manual of roughly a thousand pages, under time pressure. This section covers the navigation subsection candidates most often overlook — Section 4.3 — and then assembles every lookup taught so far into a single repeatable workflow.

1. Why an Alphabetical List Needs a Numerical Index

Section 4.2, the List of Dangerous Goods, is ordered alphabetically by Proper Shipping Name. That works perfectly when you already know the name. It fails completely in the most common real situation, which is that you are holding a Safety Data Sheet whose Section 14 gives you a UN number and little else, or an air waybill quoting UN 1993 with no usable description.

Section 4.3 — the Numerical Cross-Reference List — solves exactly that problem. It lists dangerous goods in UN and ID number order and gives, for each number, the Proper Shipping Name and the page on which the full Section 4.2 entry appears.

        START: "UN 1263"                       START: "Paint"
              |                                       |
              v                                       |
   +---------------------------+                      |
   |  SECTION 4.3              |                      |
   |  Numerical Cross-Reference|                      |
   |  UN 1263 -> Paint, p.xxx  |                      |
   +---------------------------+                      |
              |                                       |
              +-------------------+-------------------+
                                  |
                                  v
                    +-------------------------------+
                    |  SECTION 4.2 (Blue Pages)     |
                    |  Full entry, Columns A - N    |
                    +-------------------------------+

One entry in Section 4.2 can carry several packing groups, and a single UN number can appear under more than one Proper Shipping Name variant. Section 4.3 gets you to the right page; Column E of Section 4.2 then tells you which packing group row applies, and the packing group comes from the substance's own test data, not from a guess.

2. The Complete Open-Book Workflow

Every compliant consignment is built by walking the manual in the same fixed order. Learn the order and the exam becomes an exercise in reading rather than recall.

Two steps are skipped far too often. Step 4 is skipped because Column M looks like a footnote; it is not — it can forbid the shipment, change the quantity, or release it from the Regulations entirely. Step 5 is skipped because the base entry looked permissive; a state or operator variation can still stop the consignment dead.

3. Worked Lookup: From Safety Data Sheet to Declaration

Starting fact: a Safety Data Sheet Section 14 reads "UN 1263, Class 3, PG II". The customer wants 12 litres in one package, to travel on the first available flight.

1. Section 4.3 — look up 1263. It resolves to the Proper Shipping Name Paint (and to the related Paint related material entries) with a page reference into Section 4.2.
2. Section 4.2 — find the Paint entry and read across the PG II row:
   • Column C: 3 (no subsidiary risk)
   • Column D: Flammable liquid label
   • Column E: II
   • Column F: excepted quantity code
   • Columns G/H: Y341 and its limited-quantity net limit
   • Columns I/J: PI 353, 5 L
   • Columns K/L: PI 364, 60 L
   • Column M: any applicable "A" codes
   • Column N: the ERG code for the NOTOC
3. Resolve the customer's request. Twelve litres in one package exceeds the 5 L passenger aircraft limit in Column J but sits within the 60 L cargo limit in Column L. The consignment is therefore Cargo Aircraft Only: PI 364 governs, the CAO label goes on the package, and "Cargo Aircraft Only" is endorsed on the declaration and the air waybill. "The first available flight" is no longer an option if that flight is a passenger service.
4. Section 4.4 — read every code shown in Column M before finalising.
5. Section 2.8 / 2.9 — confirm nothing in the routing states or the operating carriers restricts the entry further.
6. Sections 5, 6, 7, 8 — pack to PI 364, verify the UN specification mark, apply marks and labels, and complete the declaration.

Record each column value as you read it. The acceptance agent will re-derive all of them independently from the same manual, and any mismatch between your declaration and their reading rejects the consignment.