Unit load device


A unit load device is a pallet or container used to load luggage, freight, and mail on wide-body aircraft and specific narrow-body aircraft. It allows a large quantity of cargo to be bundled into a single unit. Since this leads to fewer units to load, it saves ground crews time and effort and helps prevent delayed flights. Each ULD has its own packing list so that its contents can be tracked.
The IATA publishes ULD regulations and notes there are 900,000 in service worth more than US$1 billion, averaging $ each.

Types

ULDs come in two forms: pallets and containers. ULD pallets are rugged sheets of aluminum with rims designed to lock onto cargo net lugs. ULD containers, also known as cans and pods, are closed containers made of aluminum or combination of aluminum and Lexan, which, depending on the nature of the goods to be transported, may have built-in refrigeration units. Examples of common ULDs and their specifics are listed below.
typeinternal
volume		heightdepthbase
width		overall
width		widthcontourIATASuitability
LD3-45FulldoubleAKHAirbus A320/Airbus A321
LD2HalfsingleAPEBoeing
LD3HalfsingleAKEAirbus WB, Boeing WB, DC-10/MD-11, L-1011
LD1HalfsingleAKCBoeing WB, MD-11
LD4FullnoneAQPBoeing 767/777/787
LD8 FulldoubleAQFBoeing 767/787
LD11FullnoneALPBoeing 747, 777, 787, DC-10/MD-11
PLA palletFullnonePLA747, 777, 787
LD6 FulldoubleALF747/777/787, DC-10/MD-11
LD26 FulldoubleAAFAirbus A330, A340, A350 & Boeing 747/777/787, DC-10/MD-11
LD7 winged palletFulldoubleP1P747, 777, 787, DC-10/MD-11
LD7/P1P palletFullnoneP1PAll Widebodies
LD9 FullnoneAAPBoeing WB, DC-10/MD-11
LD29 FulldoubleAAU747
LD39 FulldoubleAMU747
P6P palletFullnoneP6P747, 767, 777, 787, DC-10, MD-11

;Notes

Aircraft compatibility

LD3s, LD6s, and LD11s will fit 787s, 777s, 747s, MD-11s, Il-86s, Il-96s, L-1011s and all Airbus wide-bodies. The 767 uses the smaller LD2s and LD8s because of its narrower fuselage. The less common LD1 is designed specifically for the 747, but LD3s are more commonly used in its place because of ubiquity. LD3s with reduced height can also be loaded on the Airbus A320 family. LD7 pallets will fit 787s, 777s, 747s, late model 767s, and Airbus wide-bodies.
Interchangeability of certain ULDs between LD3/6/11 aircraft and LD2/8 aircraft is possible when cargo needs to be quickly transferred to a connecting flight. Both LD2s and LD8s can be loaded in LD3/6/11 aircraft, but at the cost of using internal volume inefficiently. Only the LD3 of the LD3/6/11 family of ULDs can be loaded in a 767; it will occupy an entire row where two LD2s or one LD8 would otherwise have fit. Policies vary from airline to airline as to whether such transfers are allowed.
The 787, intended to replace the 767, was designed to use the LD3/6/11 family of ULDs to solve the wasted volume issue.

ULD capacity

Aircraft loads can consist of containers, pallets, or a mix of ULD types, depending on requirements. In some aircraft the two types must be mixed as some compartments take only specific ULDs.
Container capacity of an aircraft is measured in positions. Each half-width container in the aircraft it was designed for occupies one position. Typically, each row in a cargo compartment consists of two positions. Therefore, a full-width container will take two positions. An LD6 or an LD11 can occupy the space of two LD3s. An LD8 takes the space of two LD2s.
Aircraft pallet capacity is measured by how many PMC-type LD7s can be stored. These pallets occupy approximately three LD3 positions or four LD2 positions. PMCs can only be loaded in cargo compartments with large doors designed to accept them.
with its cargo door open
modelLD346×66”88×54”88×62”88×108”96×125”
Fokker 10011
CRJ2008
BAe 146-200964
ATR 72795
ATR 42563
Dash 8-3009
Xian MA60055
Short 3605
Cessna SkyCourier3

Identification

All ULDs are identified by their ULD number. A three-letter prefix identifies its type and key characteristics, followed by a 4 or 5 digit serial number to uniquely identify it from others of the same type, and ending with a two character suffix identifying the ULD's owner. For example, AKN 12345 DL means that the ULD is a forkliftable LD3 with the unique number 12345 and its owner is Delta Air Lines.
TypeBase Size Contour/Restraint

;Notes

Common prefixes

On the main deck of cargo planes are tall ULDs with footprints similar to those of or wide pallets and or long. A wide x tall ULD is half the volume of a x 88 inch pallet. The 20 foot pallet is long and wide. What the actual dimensions of contoured upper deck ULDs are is very hard to know, because most manufacturers only profile width, length and height data.
There are several common types of contoured main deck ULDs, that are contoured to provide as much cargo volume as possible. Initially ULD contouring was simply a triangle removed from one or two corners of the profile of the ULD, such as the common LD3 and LD6. Main deck ULDs use curves for the contoured shape to truly maximize cargo volume. Upper deck ULDs are just like lower deck ULDs that are either the full width of the plane with two corners of the profile removed, or that container is cut in half, down the center line of the plane,.
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.