Overview
ISO 10046:1996 specifies a uniform methodology for calculating aircraft cargo compartment volumes and defining the allowable external and internal envelopes for Unit Load Devices (ULDs). It covers both main deck and lower deck cargo compartments and sets minimum clearances and calculation rules so airlines, manufacturers and ground-handling organizations can consistently report and compare usable cargo volumes and ULD envelopes.
Key topics and technical requirements
- Scope and intent: Defines usable internal volumes for main and lower deck cargo compartments and the maximum ULD external contour and internal volume methodology.
- Usable volume vs. cumulative ULD volume: Internal compartment volumes may be listed as maximum usable volumes provided the compartment structure (floor, ceiling, sidewalls, bulkheads, nets and supports) can withstand bulk-cargo restraint loads for all flight and ground conditions (including 9g forward emergency landing). If not, reported volume must be derived from cumulative ULD volumes and marked with an asterisk (*).
- Compartment envelope limits:
- Usable length: length of floor designed to support bulk cargo; affected by barrier nets and bulkheads.
- Usable height: minimum height between floor (or roller tops) and ceiling/lining; limited by loading doorway height.
- Usable width: cross-sectional width, provided sidewall liners can withstand restraint loads; otherwise only width inboard of restraint devices is used.
- Non-parallel sides: requires accurate cross-sections applied along the compartment length to compute volume.
- Doorway and barrier effects: Volume lost due to doorway barriers must be included using planes that encompass barrier tie-down points.
- ULD envelopes and clearances:
- Containers require 51 mm (2 in) clearance to the minimum aircraft envelope; internal container volume = 93.5% of external envelope (not for forkliftable containers).
- Palletized loads require 51 mm (2 in) clearance (and 51 mm setback from pallet edges for net hardware); pallet thickness assumptions: 20 mm commercial, 57 mm military.
- Longitudinal clearances: 100 mm (4 in) where cargo aligns with aircraft structure (unless structure resists bulk loads); 150 mm (6 in) allowance for contour changes due to protrusions.
- Reference vocabulary: Uses definitions from ISO 10254:1995 (Air cargo and ground equipment - Vocabulary).
Applications and users
ISO 10046:1996 is used to:
- Standardize cargo capacity reporting for airlines and lessors (aircraft comparisons and marketing).
- Define maximum ULD contours and volumes for ULD manufacturers and suppliers.
- Support aircraft designers and certification teams when specifying cargo door sizing, restraint capability, and cargo handling systems.
- Aid load planners, ground handlers and freight forwarders in planning stowage, ULD selection and handling procedures.
Primary users: aircraft manufacturers, airlines, MROs, ULD manufacturers, regulatory authorities, cargo planners and ground-handling organizations.
Related standards
- ISO 10254:1995 - Air cargo and ground equipment - Vocabulary (normative reference)
- IATA ULD specifications (IATA 50/Series) referenced for ULD contours and configurations
Keywords: ISO 10046:1996, aircraft cargo compartment, cargo volume calculation, ULD envelope, unit load device, pallet volume, container clearance, usable cargo volume, main deck, lower deck.
