ULD’s

UNIT LOAD DEVICE

A unit load device (ULD) 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 (or manifest) so that its contents can be tracked.

The IATA publishes ULD regulations and notes there are 900,000 in service worth more than one billion USD, averaging $1100 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 (frame) and Lexan (walls), 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.

Lower hold (dimensions in cm/in)
type internal
volume
height depth base
width
overall
width
width contour IATA Suitability
LD3-45 3.7 m³ / 131 ft³ 114.3/45 153.4/60.4 156.2/61.5 243.6/95.8 Full double AKH A320
LD2 3.5 m³ 124 ft³ 162.6/64 119.4/47 156.2/61.5 Half single DPE Boeing WB
LD3 4.5 m3 / 159 ft3 156.2/61.5 200.7/79 AKE Airbus WB, Boeing WB, DC-10/MD-11, L-1011
LD1 5.0 m³ / 175 ft³ 233.7/92 AKC Boeing WB, MD-11
LD4 5.7 m3 (200 ft3) 243.8/96 243.8/96 Full none ALP 767, 777, 787
LD8 (2×LD2) 7.1 m3 / 252 ft3 317.5/125 double DQF 767/787
LD11 7.2 m3 / 256 ft3 317.5/125 none ALP 747, 777, 787, DC-10/MD-11
PLA pallet 7.1 m3 (250 ft3) PLA 747, 777, 787
LD6 (2×LD3) 8.9 m3 / 316 ft3 406.4/160 double ALF 747/777/787, DC-10/MD-11
LD26 (P1P base) 13.3 m3 (470 ft3) 223.5/88 AAF 747/777/787, DC-10/MD-11
LD7 winged pallet 14.0 m3 (495 ft3) P1P 747, 777, 787, DC-10/MD-11
LD7/P1P pallet 10.5 m3 (370 ft3) 317.5/125 none P1P All Widebodies
LD9 (P1P base) 10.8 m3 (381 ft3) AAP Boeing WB, DC-10/MD-11
LD29 (P1P base) 14.4 m3 (510 ft3) 472.4/186 double AAU 747
LD39 (P6P base) 15.9 m3 (560 ft3) 243.8/96 AMU 747
P6P pallet 11.5 m3 (407 ft3) 317.5/125 none P6P 747, 767, 777, 787, DC-10, MD-11

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 (1.143 metres (3.75 ft) instead of 1.63 metres (5.3 ft)) 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 787 was that it use the LD3/6/11 family of ULDs to solve the wasted volume issue.

ULD CAPACITY

Deck lower main
model containers 88×125″ 96×125″ 96×125″ 88×125″ 88×108″
A300-600 22 LD3 4 + 10 LD3 4 + 10 LD3 20 21
A310 15 LD3 3 + 7 LD3 3 + 7 LD3 15 16
A319 4 LD3-45
A320 7 LD3-45 11
A321 10 LD3-45 14
A330-2/800 26 LD3 8 8 22 23 26
A330-3/900 32 LD3 11 10 26 26
A340-200 26 LD3 9 9
A340-300 32 LD3 11 10
A340-500 30 LD3 10 10
A340-600 42 LD3 14 14
A350-900 36 LD3 11 11
A350-1000 44 LD3 14 14
A380-800 38 LD3 13 13
B707-320C no lower ULD 13 13
B727-100C no lower ULD 8 8
B737-200C no lower ULD 7 7
B737-300SF no lower ULD 9
B737-400SF no lower ULD 10 ½
B737-700C no lower ULD 8 8
B737-800SF no lower ULD 11 ½
B747 classic 30 LD1 28 28 36
B747SP 20 LD1
B747-400 32 LD1 9 + 4 LD1 9 + 2 LD1 30 30
B747-8/8F 40 LD1 12 + 2 LD1 34
B757-200F no lower ULD 15
B767-200 22 LD2 3 + 10 LD2 3 + 10 LD2
B767-300 30 LD2 4 + 14 LD2 4 + 14 LD2 14 16 26
B767-400 38 LD2
B777-200 32 LD3 10 + 2 LD3 10 27
B777-300 44 LD3 14 + 2LD3 14
B777-9 48 LD3 16 14 + 4 LD3
B787-8 28 LD3 9 8 + 2 LD3
B787-9 36 LD3 11 11
B787-10 40 LD3 13 13
DC-8-55F no lower ULD 13
DC-8-62/72F no lower ULD 14
DC-8-61/63/71/73F no lower ULD 18
DC-9-15F no lower ULD 6
DC-9-32F no lower ULD 8
MD-80SF no lower ULD 8 8 12
DC-10 26 LD3 5 + 8 LD3 22 30
MD-11 32 LD3 6 + 14 LD3 26 26 34
L-1011 19 LD3 4 + 7 LD3
Il-86/Il-96-300 16 LD3
Il-96M/T 32 LD3

^ The B727-200 had an option to hold 11 specific 45.5 in–92.4 in × 41.1 in × 43.4 in (1.16 m–2.35 m × 1.04 m × 1.10 m) base-full width x height x depth, 78 cu ft (2.2 m3) underfloor containers.

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 96 by 125 in (240 by 320 cm) 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).