Air cargo metrics: tonnes, CTK, ACTK and load factor

Weight alone misses the distance

Cargo tonne-kilometres (CTK) multiply carried cargo mass by stage distance; available cargo tonne-kilometres (ACTK) measure offered capacity over distance. In a hypothetical example, carrying 12 tonnes for 2,000 km produces 24,000 CTK. Offering 20 tonnes over that stage produces 40,000 ACTK. Neither figure is a count of shipments or a revenue amount.

IATA

Calculate and aggregate the load factor

The example’s cargo load factor is 24,000 ÷ 40,000 = 60%. For several stages, sum CTK and ACTK separately, then divide. Do not average stage percentages without their capacity weights. If a company reports freight tonnes while another reports CTK, a longer average stage can make their growth rates diverge even with the same mass carried.

Volume can bind before weight

A shipment may fill the available hold volume before reaching the aircraft’s weight allowance. Belly capacity also competes with passenger baggage and operational weight limits. A network-wide load factor therefore does not establish that a particular departure has room for a particular shipment, or that high utilization produced a profit.

A comparison checklist

Read the period, units, geographic scope, whether freight and mail are included, and whether the report covers operated or marketed services. Compare international cargo with international cargo. Keep actual traffic separate from available capacity and financial yield. These calculations are educational examples, not actual airline results.