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Unit Load Device

Overview

A unit load device, is a pallet

Pallet

A pallet , sometimes called a skid, is a flat transport structure that supports goods in a stable fashion while being lifted by a forklift, pallet jack, front loader or other jacking device. A pallet is the structural foundation of a unit load which allows handling and storage efficiencies...

or container

Intermodal container

An intermodal container is a standardized reusable steel box used for the safe, efficient and secure storage and movement of materials and products within a global containerized intermodal freight transport system...

used to load luggage, freight, and mail on wide-body aircraft

Wide-body aircraft

A wide-body aircraft is a large airliner with two passenger aisles, also known as a widebody aircraft or twin-aisle aircraft. The typical fuselage diameter is . In the typical wide-body economy cabin, passengers are seated seven to ten abreast, allowing a total capacity of 200 to 850 passengers...

and specific narrow-body aircraft

Narrow-body aircraft

A narrow-body aircraft is an airliner with a fuselage aircraft cabin width typically of 3 to 4 metres , and airline seat arranged 2 to 6 abreast along a single aisle...

. 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 (or manifest) so that its contents can be tracked.

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What is maximume floor limatation for load a LD3 and PMC, Pag for airbus A330.

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Encyclopedia

A unit load device, is a pallet

Pallet

A pallet , sometimes called a skid, is a flat transport structure that supports goods in a stable fashion while being lifted by a forklift, pallet jack, front loader or other jacking device. A pallet is the structural foundation of a unit load which allows handling and storage efficiencies...

or container

Intermodal container

An intermodal container is a standardized reusable steel box used for the safe, efficient and secure storage and movement of materials and products within a global containerized intermodal freight transport system...

used to load luggage, freight, and mail on wide-body aircraft

Wide-body aircraft

A wide-body aircraft is a large airliner with two passenger aisles, also known as a widebody aircraft or twin-aisle aircraft. The typical fuselage diameter is . In the typical wide-body economy cabin, passengers are seated seven to ten abreast, allowing a total capacity of 200 to 850 passengers...

and specific narrow-body aircraft

Narrow-body aircraft

A narrow-body aircraft is an airliner with a fuselage aircraft cabin width typically of 3 to 4 metres , and airline seat arranged 2 to 6 abreast along a single aisle...

. 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 (or manifest) so that its contents can be tracked.

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 (frame) and Lexan

Lexan

Lexan is a registered trademark for SABIC Innovative Plastics' brand of polycarbonate resin thermoplastic. Polycarbonate polymer is produced by reacting bisphenol A with carbonyl dichloride, also known as phosgene. Lexan is the brand name for polycarbonate sheet and resin in a wide range of grades...

(walls), which, depending on the nature of the goods to be transported, may have built-in refrigeration

Refrigeration

Refrigeration is a process in which work is done to move heat from one location to another. This work is traditionally done by mechanical work, but can also be done by magnetism, laser or other means...

units. Examples of common ULDs and their specifics are listed below.

Volume indicated is internal volume.
Container type	Volume	Linear dimensions (base width / overall width × depth × height)	Remarks
LD1	4.9 m³ (173 cu ft)	156 / 234 × 153 × 163 cm (61.5 / 92 × 60.4 × 64 in)	contoured, half width
LD2	3.4 m³ (120.1 cu ft)	119 / 156 × 153 × 163 cm (47 / 61.5 × 60.4 × 64 in)	contoured, half width
LD3	4.5 m³ (158.9 cu ft)	156 / 201 × 153 × 163 cm (61.5 / 79 × 60.4 × 64 in)	contoured, half width, dimension according to IATA; available at 45" height for loading on Airbus A320 family
LD6	8.95 m³ (316.1 cu ft)	318 / 407 × 153 × 163 cm (125 / 160 × 60.4 × 64 in)	contoured, full width, equivalent to 2 LD3s
LD8	6.88 m³ (243 cu ft)	244 / 318 × 153 × 163 cm (96 / 125 × 60.4 × 64 in)	contoured, full width, equivalent to 2 LD2s; DQF-prefix
LD11	7.16 m³ (252.9 cu ft)	318 × 153 × 163 cm (125 × 60.4 × 64 in)	same as LD-6 but without contours; rectangular
Pallet type	Volume	Linear dimensions	Remarks
LD8	6.88 m³ (243 cu ft)	153 × 244 cm (60 × 96 in)	same floor dimensions as container variant; FQA-prefix
LD11	7.16 m³ (252.9 cu ft)	153 × 318 cm (60.4 × 125 in)	same floor dimensions as container variant; FLA- and PLA-prefixes
LD7 (2 pallet variants)	10.8 m³ (381.4 cu ft) 11.52 m³ (406.8 cu ft)	224 × 318 cm (88 × 125 in) 244 × 318 cm (96 × 125 in)	PAG- and P1P-prefixes PMC- and P6P-prefixes

Pallet volumes shown are built 64 in tall for lower deck loading. Height limit for main deck depends on aircraft type.

Aircraft compatibility

LD3s, LD6s, and LD11s will fit 787s

Boeing 787

The Boeing 787 Dreamliner is a long-range, mid-size wide-body, twin-engine jet airliner developed by Boeing Commercial Airplanes. It seats 210 to 290 passengers, depending on the variant. Boeing states that it is the company's most fuel-efficient airliner and the world's first major airliner to use...

, 777

Boeing 777

The Boeing 777 is a long-range, wide-body twin-engine jet airliner manufactured by Boeing Commercial Airplanes. It is the world's largest twinjet and is commonly referred to as the "Triple Seven". The aircraft has seating for over 300 passengers and has a range from , depending on model...

s, 747

Boeing 747

The Boeing 747 is a wide-body commercial airliner and cargo transport, often referred to by its original nickname, Jumbo Jet, or Queen of the Skies. It is among the world's most recognizable aircraft, and was the first wide-body ever produced...

s, MD-11

McDonnell Douglas MD-11

The McDonnell Douglas MD-11 is a three-engine medium- to long-range widebody jet airliner, manufactured by McDonnell Douglas and, later, by Boeing Commercial Airplanes. Based on the DC-10, it features a stretched fuselage, increased wingspan with winglets, refined airfoils on the wing and smaller...

s, Il-86

Ilyushin Il-86

The Ilyushin Il-86 is a medium-range wide-body jet airliner. It was the USSR's first wide-body and the world's second four-engined wide-body...

s, Il-96

Ilyushin Il-96

The Ilyushin Il-96 is a four-engined long-haul widebody airliner designed by Ilyushin in the Soviet Union and manufactured by the Voronezh Aircraft Production Association in Voronezh, Russia...

s, L-1011

Lockheed L-1011

The Lockheed L-1011 TriStar, commonly referred to as the L-1011 or TriStar, is a medium-to-long range, widebody passenger trijet airliner. It was the third widebody airliner to enter commercial operations, following the Boeing 747 and the McDonnell Douglas DC-10. Between 1968 and 1984, Lockheed...

s and all Airbus

Airbus

Airbus SAS is an aircraft manufacturing subsidiary of EADS, a European aerospace company. Based in Blagnac, France, surburb of Toulouse, and with significant activity across Europe, the company produces around half of the world's jet airliners....

wide-bodies. The 767

Boeing 767

The Boeing 767 is a mid-size, wide-body twin-engine jet airliner built by Boeing Commercial Airplanes. It was the manufacturer's first wide-body twinjet and its first airliner with a two-crew glass cockpit. The aircraft features two turbofan engines, a supercritical wing, and a conventional tail...

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 (45" instead of 64") can also be loaded on the Airbus A320 family. LD7 pallets will fit 787s, 777s, 747s, late model 767s (with the big door), 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.

One of the design requirements of the 767's replacement, the 787, was for it 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. The table below indicates the maximum capacity of an aircraft for all-container and all-pallet configurations. 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 (96" × 125") can be stored. These pallets occupy approximately three LD3 positions (it occupies 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).

A = Airbus; B = Boeing; L = Lockheed; MD = McDonnell-Douglas; F = freighter; ER = extended range; LR = long range
Aircraft	Max Container Cap.	Max Pallet Cap.	Remarks
B727-100F	none	8 pallets*	*88" × 125" pallets only; the 727 Boeing 727 The Boeing 727 is a mid-size, narrow-body, three-engine, T-tailed commercial jet airliner, manufactured by Boeing. The Boeing 727 first flew in 1963, and for over a decade more were built per year than any other jet airliner. When production ended in 1984 a total of 1,832 aircraft had been produced... is a narrow-body
B727-200F	none	12 pallets*	*88" × 125" pallets only; the 727 Boeing 727 The Boeing 727 is a mid-size, narrow-body, three-engine, T-tailed commercial jet airliner, manufactured by Boeing. The Boeing 727 first flew in 1963, and for over a decade more were built per year than any other jet airliner. When production ended in 1984 a total of 1,832 aircraft had been produced... is a narrow-body
B727-200C (combi)	none	11 pallets*	*88" × 125" pallets only; the 727 Boeing 727 The Boeing 727 is a mid-size, narrow-body, three-engine, T-tailed commercial jet airliner, manufactured by Boeing. The Boeing 727 first flew in 1963, and for over a decade more were built per year than any other jet airliner. When production ended in 1984 a total of 1,832 aircraft had been produced... is a narrow-body
B757-200F	13 SAAs* or 28 AYYs	14 PAGs	*Position 14 is AYYs only
B747-100/200/300	30 LD1s	5 pallets + 14 LD1s
B747-400	32 LD1s	5 pallets + 14 LD1s
B747-400ER	26 LD1s	4 pallets + 14 LD1s
B747-400F/ERF	32 LD1s (lower deck) + 30 pallets (main deck)		freighter aircraft, capacity includes all decks
B767-200	22 LD2s	3 pallets + 10 LD2s
B767-300	30 LD2s	4 pallets + 14 LD2s
B767-300ER	30 LD2s	4 pallets + 14 LD2s
B767-300F	24 pallets* (main deck) + 30 LD2s (lower deck)		*accepts 88" × 125" pallets only; freighter aircraft
B767-400ER	38 LD2s	5 pallets + 18 LD2s
B777-200/200ER/200LR	32 LD3s	6 pallets
B777F	30 LD3s + 27 pallets	37 pallets	freighter aircraft, capacity includes all decks
B777-300/300ER	44 LD3s	8 pallets
B787-8/-3	28 LD3s	9 pallets
B787-9	36 LD3s	11 pallets
A300B2/B4	20 LD3s	?
A300-600	22 LD3s	4 pallets + 10 LD3s
A300-600F	41 LD3s	25 pallets	freighter aircraft, capacity includes all decks A300-600F deck layout
A310	14 LD3s	3 pallets
A319	4 LD3-45W + 1 LD3/40		Note LD3 height only 45"; add. cont. acc. IATA contour H
A320	7 LD3-45W		Note LD3 height only 45"; add. cont. acc. IATA contour H
A320PF	10 pallets* (main deck) + 7 LD3-45W (lower deck)	10 AAZ (main deck) + 7 LD3-45W (lower deck)	*accepts 88" × 125" pallets only; freighter aircraft equipped with fwd cargo 86×121" door
A321	10 LD3-45W		Note LD3 heigh only 45"; add. cont. acc. IATA contour H
A321PF	13 pallets* (main deck) + 10 LD3-45W (lower deck)	13 AAZ (main deck) + 10 LD3-45W (lower deck)	*accepts 88" × 125" pallets only; freighter aircraft equipped with fwd cargo 86×121" door
A330-200	23 pallets or 26 LD3s	8 pallets + 2 LD3s
A330-200F	9 AMA containers + 4 pallets (main deck) + 26 LD3 (lower deck)	22 pallets (main deck) + 8 pallets + 2 LD3 (lower deck)	freighter aircraft, capacity includes all decks A330-200F deck layout
A330-300	32 LD3s	11 pallets
A340-200	26 LD3s	9 pallets
A340-300	32 LD3s	11 pallets
A340-500	30 LD3s	10 pallets
A340-600	42 LD3s	14 pallets
A380-800	38 LD3s	13 pallets
A380-800F	59–71 LD3s	66 pallets	freighter aircraft, capacity includes all decks A380-800F deck layout
MD-11	32 LD3s	26 pallets
L-1011	16 LD3s	none	all series except 500 (250/200/150/100/50/1 series)
L-1011-500	19 LD3s	4 pallets*	*if equipped with fwd cargo 104" door
Il-86	16 LD3s	?
Il-96	18 LD3s	?

Maximum capacity shown does not reflect weight restrictions.
Actual number of ULDs loaded may be lower if aircraft is at its weight limit.

Identification

All ULDs are identified by their ULD number. A three-letter prefix identifies its type, followed by a 4 or 5 digit serial number (4 if prior to October 1, 1993; either 4 or 5 if post 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

Delta Air Lines

Delta Air Lines, Inc. is a major airline based in the United States and headquartered in Atlanta, Georgia. The airline operates an extensive domestic and international network serving all continents except Antarctica. Delta and its subsidiaries operate over 4,000 flights every day...

.

Common prefixes

AAA: LD7 container (88" x 125"), 81" tall, contoured for maindeck narrow-body
AAD: LD7 container (88" x 125"), 96" tall, contoured for maindeck wide-body (aka A1)
AAF: LD26 container
AAP: LD9
AAU: LD29 container
AAY: LD7 container (88" x 125"), 81" tall, contoured for maindeck wide-body and narrow-body (aka A2)
AAZ: LD7 container (88" x 125"), 64" 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
AKH, AKW: LD3-45 mainly for A320/321, same base as AKE, extensions on both sides, 45 inches high
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 (96" x 125"), 96" tall, contoured for maindeck 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
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 (88" x 125"), folding wings for overhang
PAD: LD7, large pallet (88" x 125"), flat
PGA: M6, large pallet, 96 by 238.5 inches. freighter main deck only
PLA: LD11 pallet
PMC: LD7, large pallet (96" x 125")
QKE: LD3 same as AKE but made of KEVLAR and designed to be bombproof. Has no forklift holes
RAP: LD9 with refrigeration unit
RAU: LD29 container with refrigeration unit
RKN: LD3 with refrigeration unit
RWB: LD11 with refrigeration unit
VRA: M6, large pallet, 96 by 196 inches. Twin car rack
XAW: LD7, large pallet (88" x 125"), fixed wings for overhang

Position 1 letter identifies ULD category (certification, ULD type, thermal units);
Position 2 letter identifies standard base dimensions:;
Position 3 letter identifies contour, forklift holes, and other miscellaneous information.

Miscellaneous information

LD3s and LD2s occupy half the width of the cargo bin of the aircraft they are designed for, therefore are loaded two at a time, side-by-side, except Airbus A320 family which is so narrow, that only one LD3 can be loaded.
LD6s and LD8s are, respectively, their full width counterparts and can only be loaded one at a time.
LD2s and LD8s are ULDs designed specifically for one type of aircraft, the 767. This is because the 767 has a narrower fuselage than other wide-body aircraft.
LD1s are ULDs designed specifically for the 747. But LD3s are more commonly used in its place because of ubiquity.
LD7s inexplicably come in two different floor dimensions.
Maximum height for all ULDs is 64" for lower deck of aircraft, except Airbus A320 family, where it is 45".
The most common form of ULD damage are holes in container walls from improper forklifting.

Main-deck ULDs

On the main deck of cargo planes are 79 to 96 in (2,006.6 to 2,438.4 mm) tall ULDs with footprints similar to those of 88 inches (2,235 mm) or 96 inches (2,438 mm) wide pallets and 62 inches (1,575 mm) or 125 inches (3,175 mm) long. A 62 inches (1,575 mm) wide x 88 inches (2,235 mm) tall ULD is half the volume of a 125 inches (3,175 mm) x 88 inch pallet. The 20 foot pallet is 238 inches (6,045 mm) long and 96 inches (2,438 mm) wide.

There several common types of contoured main deck ULDs, that are contoured (curved to fit in the plane) 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, and upper deck AYY), 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 planes width and each missing one profile corner, but often twice or four times as long from planes nose to tail.

Many air cargo companies use main deck ULDs that have both features called dual-profile, so that on small 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.

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.

External links

Air Freight Container Specifications