Unit load device

A unit load device (ULD) is a container used to load luggage, freight, and mail on wide-body aircraft and specific narrow-body aircraft. It allows preloading of cargo, provided the containerised load fits in the aircraft, enabling efficient planning of aircraft weight and balance and reduced labour and time in loading aircraft holds compared with 'bulk-loading' single items of cargo or luggage by hand. Each ULD has its own packing list or manifest so that its contents can be tracked. A loaded aircraft cargo pallet secured with a cargo net also forms a ULD, but its load must be gauged for size in addition to being weighed to ensure aircraft door and hold clearances.

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 aluminium with rims designed to lock onto cargo net lugs. ULD containers, also known as cans and pods, are closed containers often made of aluminium or a combination of aluminium (frame) and Lexan (walls) but there are examples of containers made of GRP with an insulating foam core. Depending on the nature of the goods to be transported, ULDs may have built-in refrigeration units. Examples of common ULDs and their specifics are listed below.

+ Lower hold containers volume in m3 (cu.ft), dimensions in mm (inches) Type Internalvolume Height Depth Width Contour IATA Suitability Base Overall Nominal LD3-45 Full Double AKH Airbus A319/A320/A321 LD2 Half Single APE Boeing widebodies LD3 AKE Airbus and Boeing widebodies, DC-10/MD-11, L-1011 LD1 AKC Boeing widebodies, MD-11 LD4 Full None AQP Boeing 767/777/787 LD8 (2×LD2) Double AQF Boeing 767/787 LD11 None ALP Boeing 747, 777, 787, DC-10/MD-11 PLA pallet PLA 747, 777, 787 LD6 (2×LD3) Double ALF 747/777/787, DC-10/MD-11 LD26 (P1P base) AAF Airbus A330, A340, A350, and Boeing 747/777/787, DC-10/MD-11 LD7 winged pallet P1P 747, 777, 787, DC-10/MD-11 LD7/P1P pallet None P1P All widebodies LD9 (P1P base) AAP Boeing widebodies, DC-10/MD-11 LD29 (P1P base) Double AAU 747 LD39 (P6P base) AMU 747 P6P pallet None P6P 747, 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 (they have the same floor dimensions such that one LD3 takes the place of one LD1). LD3s with reduced height ( instead of ) can also be loaded on the Airbus A320 family. LD7 pallets will fit 787s, 777s, 747s, late model 767s (with larger doors), 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 (33 ft3 wasted per LD2). 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 (90 ft3 wasted per LD3). 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

+ Widebodies Model Lower deck Main deck Containers 88×125″ 96×125″ 96×125″ 88×125″ 88x108″ Airbus A300-600 LD3 4 + 10 LD3 4 + 10 LD3 20 21 Airbus A310 LD3 3 + 7 LD3 3 + 7 LD3 15 16 Airbus A330-2/800 LD3 Airbus A330-3/900 LD3 26 26 Airbus A340-200 LD3 Airbus A340-300 LD3 Airbus A340-500 LD3 Airbus A340-600 LD3 Airbus A350-900 LD3 Airbus A350F 40 LD3 12 30 Airbus A350-1000 LD3 Airbus A380-800 LD3 Boeing 747 classic 28 28 36 Boeing 747SP Boeing 747-400 9 + 4 LD1 9 + 2 LD1 30 30 Boeing 747-8/8F 12 + 2 LD1 Boeing 767-200 3 + 10 LD2 3 + 10 LD2 Boeing 767-300 4 + 14 LD2 4 + 14 LD2 14 Boeing 767-400 5 + 16 LD2 Boeing 777-200 LD3 + 2 LD3 27 Boeing 777-300 LD3 + 2LD3 33 Boeing 777-8F 40 LD3 13 31 Boeing 777-9 LD3 + 4 LD3 Boeing 787-8 LD3 + 2 LD3 Boeing 787-9 LD3 Boeing 787-10 LD3 Douglas DC-10 LD3 5 + 8 LD3 22 30 McDonnell Douglas MD-11 LD3 6 + 14 LD3 26 26 34 Lockheed L-1011 LD3 4 + 7 LD3 Ilyushin Il-86/Il-96-300 16 LD3 Ilyushin Il-96M/T 32 LD3

+ Narrowbodies Model Containers 96×125″ 88×125″ 88x108″ Airbus A319 LD3-45 Airbus A320 LD3-45 11 Airbus A321 LD3-45 14 Boeing 707-320C no lower ULD 13 13 Boeing 727-100C no lower ULD 8 8 Boeing 737-200C no lower ULD 7 7 Boeing 737-300SF no lower ULD 9 Boeing 737-400SF no lower ULD 10 ½ Boeing 737-700C no lower ULD 8 8 Boeing 737-800SF no lower ULD 11 ½ Boeing 757-200F no lower ULD 15 Comac C919 LD3-46 Douglas DC-8-55F no lower ULD 13 Douglas DC-8-62/72F no lower ULD 14 Douglas DC-8-61/63/71/73F no lower ULD 18 Douglas DC-9-15F no lower ULD 6 Douglas DC-9-32F no lower ULD 8 McDonnell Douglas MD-80SF no lower ULD 8 8 12

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 (LD1/LD2/LD3) 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 (LD6/LD8/LD11) 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 (two positions of one row and half of the two positions of the following row) or four LD2 positions. PMCs can only be loaded in cargo compartments with large doors designed to accept them (small door compartments are container-only).

+ Regional airliners Model LD3 46×66” 88×54” 88×62” 88×108” 96×125” Fokker 100 11 CRJ200 8 BAe 146-200 9 6 4 ATR 72 7 9 5 ATR 42 5 6 3 Dash 8-300 9 Xian MA600 5 5 Short 360 5 Cessna SkyCourier 3

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 (4 if prior to October 1, 1993; either 4 or 5 if after October 1, 1993) to uniquely identify it from others of the same type, and ending with a two character (alpha-numerical) suffix identifying the ULD's owner (if an airline, often the same as IATA designator codes). 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.

+ IATA ULD prefix Type Base size (depth × base width) Contour/restraint (overall width × height) Notes

Common prefixes

AAA: LD7 container (), tall, contoured for maindeck narrow-body AAD: LD7 container (), tall, contoured for maindeck wide-body (aka A1) AAF:"Boeing Cargo" , Boeing, March 2012. LD26 container AAP: LD9 AAU: LD29 container AAY: LD7 container (), tall, contoured for maindeck wide-body and narrow-body (aka A2) AAZ: LD7 container (), tall, contoured for maindeck wide-body and narrow-body and any belly (aka L9) AGA: M2 container AKC: LD1 without forklift holes AKE: LD3 without forklift holes/half ALF AKH, AKW: LD3-45 mainly for A320/321, tall, same base as AKE, extensions on both sides AKN: LD3 with forklift holes ALB: LD4 with forklift holes ALD: LD11 container (aka L11) ALF: LD6 without forklift holes ALP: LD11 without forklift holes ALP: LD4 without forklift holes AMA: M1 container AMD: M1H container AMJ: LD7 container (), tall, contoured for main deck wide-body (aka M1) AMU: LD39 container contour similar to ALF, but deeper and bigger extensions. biggest lower-deck container AVY: LD1 with forklift holes AWC: LD6 with forklift holes AYY: Demi, a half-width contoured container typically used for the main deck AYX: AYY with fittings to connect a fire extinguisher so as to carry Dangerous Goods DPE: LD2 without forklift holes DPN: LD2 with forklift holes DQF: LD8 with forklift holes FLA: LD11 pallet FQA: LD8 pallet (same floor dimensions as DQF) HMA: Horse stall KMA: Sheep and goat pen P1P: LD7, large pallet (), folding wings for overhang PAD: LD7, large pallet (), flat PGA: M6, large pallet (), freighter main deck only PLA: LD11 pallet PMC: LD7, large pallet () QKE: LD3 same as AKE but made of KEVLAR and designed to be bombproof. No forklift holes. RAP: LD9 with refrigeration unit RAU: LD29 container with refrigeration unit RKN: LD3 with refrigeration unit RWB: LD11 with refrigeration unit SAA: Full-sized version of the AYY SAX: Full-sized version of the AYX VRA: M6, large pallet (), twin car rack XAW: LD7, large pallet (), fixed wings for overhang XKC: LD3 without forklift holes/half ALF

Main-deck ULDs

On the main deck of cargo planes are tall ULDs with footprints similar to those of or wide pallets and or long. A wide × tall ULD is half the volume of a × 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 (curved to fit in the plane's body) 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 (lower deck LD6 lower), or that container is cut in half, down the center line of the plane, (lower deck LD3 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.

Unit load device

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