What is an Aircraft ULD?

A Unit Load Device (ULD) is a container or pallet used to load freight, baggage, and mail onto aircraft. ULDs are designed to fit perfectly into an aircraft’s cargo hold and are essential to modern air cargo and passenger operations.

Types of ULDs

• Container ULDs: LD1, LD3, LD3 Reefer, LD9, LD11, LD26, LD29
• Pallet ULDs: M6, LD7, PMC, MDP, M1, M2

Common ULD Specifications

ULD Type	Code	Dimensions (cm)	Tare Weight (kg)	Max Gross Weight (kg)	Illustration
LD1	AKC	153 x 153 x 162	70	1,588
LD3	AKE	153 x 156 x 163	70	1,588
LD3 Reefer	RKN	153 x 156 x 163	200	1,588
LD9	AAZ	318 x 244 x 163	180	6,804
LD11	AKE	317 x 153 x 163	160	6,804
LD26	ALN	317 x 244 x 163	210	7,000
LD29	AMA	317 x 244 x 239	350	11,300
M6	PGA	318 x 244	120	6,804
LD7	PAG	318 x 244	120	6,804
PMC	PMC	244 x 318	120	6,804
MDP	MDP	244 x 318	159	6,804
M1	PLA	605 x 244	220	11,300
M2	PGE	605 x 244	240	11,300

How Are ULDs Used in Airfreight?

1. Consolidation of Cargo

Ground handlers or freight forwarders load goods into ULDs before reaching the aircraft, reducing the need for individual handling.

2. Loading into Aircraft

ULDs are moved on dollies and loaded using specialized equipment like high loaders. Each ULD matches the aircraft model for optimal fit.

3. In-Flight Safety

ULDs secure cargo during flight, maintaining weight balance and preventing shifting or damage during takeoff, turbulence, or landing.

4. Unloading and Delivery

At the destination, ULDs are offloaded and unpacked at cargo terminals, then returned for reuse.

Benefits of Using ULDs

• Efficiency: Speeds up cargo loading/unloading
• Protection: Reduces damage and loss during transit
• Standardization: Global compatibility across airlines
• Cost Savings: Less ground handling and faster turnarounds

ULDs are to air cargo what containers are to ocean freight: essential tools for global logistics and aviation safety.