After a roughly 2.5h weather delay, Boeing's first 747-8F, the largest western-built commercial freighter, has lifted off on its maiden sortie.

The aircraft - designated RC501 - lifted off from runway 34L at 12:39PST from Boeing's Everett, Washington, facility at Paine Field.

Powered by General Electric GEnx-2B engines, the aircraft took to the sky under the control of 747 chief project pilot Mark Feuerstein and test engineer Tom Immrich. The event kicks off a year-long 1,600hr programme of flights for the new 747, whose test regime will also include 2,100hr of ground work.



Initial airworthiness and flutter trials will be conducted at Grant County International Airport in Moses Lake, Washington, 230km east of Seattle. Following the early round of tests, RC501 will be joined by RC521 and RC522 in Palmdale, California, where the flight-test operation will be based.

The first flight comes more than a year after the December 2008 date originally planned by Boeing. Closure of the 747-400 line, resource starvation, a machinist strike and late design changes added up to a delay of just over a year to the new freighter.

Boeing's 747-8F features a new super-critical wing, expanded use of advanced composites, new engines, an updated flight deck, and lateral fly-by-wire controls of its ailerons and spoilers as well as 16% more cargo volume over its processor, the 747-400ERF. It has a 442,000kg (975,000lb) maximum take-off weight and a range of 8,135km (4,390nm).

RC501 is expected to land back at Paine Field after a three- to five-hour test flight over Washington state.

Luxembourg-based Cargolux is to take delivery of the first 747-8F, currently in production, in the fourth quarter of 2010.

Both Boeing and Airbus will spend 2010 flight-testing new freighters at a time when the market for air freight has fallen sharply due to the global recession. Airbus' A330-200F, which made its debut at the Singapore Air Show last week, is due for delivery in June or July to Etihad Crystal Cargo.

The slowing demand for large cargo aircraft forced Boeing to absorb a $360 million charge last year as it was forced to maintain production at a lower-than-planned rate of 1.5 aircraft per month, in addition to a $640 million charge from higher production costs.

Boeing holds orders for 108 747-8s including 76 freighters and 32 'Intercontinental' passenger aircraft, a type due to enter service in late 2011.

The 747-8F, at 76.3m (250ft), is the longest commercial aircraft ever built by Boeing and the world's second-longest after the six-engined Antonov An-225 at 84m.

First flight of the 747-8F comes one day ahead of the 41st anniversary of the maiden flight of the 747-100, from the same runway, on 9 Feb 1969. Boeing has inscribed the initials 'JW' - those of the 747-100's pilot, Jack Waddell - on the nose-gear as a tribute.

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