Boeing 747-400ERF

The 747-400ERF is the freighter version of the 747-400ER, and it succeeded where the passenger version did not: 40 were built, against six of the airliner.

It was launched on 30 April 2001 and delivered to Air France, via ILFC, on 17 October 2002.

What it adds

Maximum takeoff weight	910,000 lb (413,000 kg)
Maximum payload	248,600 lb (112,760 kg)
Range	About 9,200 km

Against a standard 747-400F, the operator chooses between:

• 22,000 lb (9,980 kg) more payload, or
• 525 nautical miles (972 km) more range

The airframe is strengthened to carry it: reinforced fuselage, landing gear and sections of the wing, with new, larger tyres.

Why the freighter sold and the airliner did not

The 747-400ER attracted exactly one customer. The -400ERF attracted forty. The difference is worth understanding, because it explains something about how freight economics differ from passenger economics.

A passenger airline sizes an aircraft to a route's demand. Very few routes needed more than a standard 747-400 could carry, so the -400ER solved a problem almost nobody had.

Cargo operators have the opposite constraint. Carriers such as Cargolux routinely move machinery and indivisible loads - single items that cannot be split across two flights. For that work, maximum payload and landing weight are hard limits, and an extra 22,000 lb is the difference between accepting a shipment and turning it down.

It is also why cargo range figures are quoted at maximum payload, not at maximum fuel. A freighter's useful range is what it can fly while full.

How the weight was spent

When Boeing launched the ERF, the whole 35,000 lb increase in MTOW over the -400F (from 875,000 to 910,000 lb) was available as extra fuel - burned off in flight so the aircraft landed at the same weight as a standard -400F. That is what produced the extra range.

The 747-8F has a higher zero-fuel weight limit and more container volume. Boeing's current planning examples identify different empty weights and weight options, so compare those configurations before drawing conclusions about payload or range. The freighter specification table sets out the assumptions.

That trade - payload against range, decided at the design stage - is the clearest single difference between the last two generations of 747 freighter.