and upper deck AAX). Main deck ULDs and pallets are not only taller than lower deck ULDs, they are frequently two or four times longer. They are usually organized like an LD6, using the width of the plane and missing two profile corners, or two very long LD3s, stored in parallel to use the plane's width and each missing one profile corner, but often twice or four times as long from plane's nose to tail. Many air cargo companies use main deck ULDs that have both features called dual-profile, so that on smaller planes such as the Boeing 727, they are stored widthwise and have two corners contoured, and on the bigger Boeing 767, they can be rotated 90 degrees and shipped in parallel like LD3s, so that only one corner is contoured when being used like an LD3. This greatly simplifies transportation of cargo containers at slight cost of cargo volume. See also 463L master pallet, used for military aircraft transport and airdrops AAR Corp, parent company of Nordisk Aviation, a manufacturer of ULDs Containerization Intermodal container Pallet Rio Tinto Alcan, formerly Alusuisse, a manufacturer of ULDs Shipping container Unit load References External links Civil aviation Shipping containers Air freight