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Boeing 747 profile
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 The big leap forward

Beyond the iconic hump of the 747 and cross-section that has made the type so recognisable, Boeing's new 747-8F bears little resemblance to its -100 predecessor. At a length of 76.4m (249.8ft), the 747-8 is Boeing's longest aircraft to date, eclipsing the 777-300ER by 2.5m.

On the move: the first 747-8 left the paint hanger in November 2009, and is now almost ready to fly
© Boeing
On the move: the first 747-8 left the paint hanger in November 2009, and is now almost ready to fly

 

Even with all its new enhancements, Boeing hopes to build on its foundation, fortified by delivering 1,418 747s since the first Jumbo was handed over at the end of 1969.

"The basis of the 747-8 is to capture the great features that we have on the 747-400 and not to lose that while we're stretching the airplane and improving the performance," says Mohammad (Mo) Yahyavi, vice-president and general manager of the 747 programme.

COMPOSITES

While it will be included in the 747 type certificate, granted four decades ago, Boeing is quick to say that the -8 model is a big leap forward. Structurally, the 747-8 features a greater use of composites, new super-critical wing and raked wingtip and larger empennage. Under its skin, Boeing has adopted a new primary flight control system and logic and a new Honeywell flight management system, along with, for the first time on a 747, lateral fly-by-wire for the wing's new spoilers and ailerons, as well as a ram air turbine supplied by Hamilton Sundstrand.

While maintaining the overall ergonomics of the 747-400 flightdeck for commonality, Boeing has incorporated 787-style symbology on the 747's six liquid-crystal displays, as well as a vertical situation display, electronic checklists, airport moving map display and a cursor control knob interface.

Yahyavi says that all these changes to the aircraft will be part of an amended 747 type certificate, that draws on the lessons learned from the 737 Next Generation programme that ran into certification challenges around the aircraft's overwing exits and differences from the 737 Classic.

Yahyavi says Boeing has worked closely with the US Federal Aviation Administration and that there are "no surprises right now", adding that "everybody knows exactly what needs to be done".

Boeing 747 cutaway
© Flight International/John Marsden 1968
Click on image for full size version

 

The first 747-8F came to life when power-on testing began in the early morning hours of 14 August. Over the months that followed, the aircraft was run through a series of comprehensive functional check-outs in the factory system by system, hardware and software, to verify the "total integration of the airplane in the factory", says Yahyavi.

This process was "time consuming", he adds, as issues were discovered and ultimately prompted a schedule slip of three months as the company took more time to complete these tests.

RC501, the first 747-8F, moved from the factory to the paint hangar on 12 November, followed by a move to the fuel dock six days later and the first run of its General Electric GEnx-2B engines on 9 December. The -2B engines and their pneumatic architecture are modified from the baseline -1B engines designed for the more-electric 787.

The aircraft is now parked on the Everett flightline undergoing a series of engineering work authorisation (EWAS) tests to validate the functionality of the new flight controls and all the aircraft's systems. Yahyavi says the preparations are far along and are intended to tease out any remaining bugs in the systems by operating elements of the aircraft under a variety of failure modes to evaluate system responses in both air and ground modes.

The gauntlet tests were run in late December on the engineering cab or "eCab", which ties together the flight control, autoflight, pilot interface to simulate flight. Those same tests will be duplicated on RC501 as part of the "Final Gauntlet" tests that will "duplicate and verify" the profile of a standard Boeing production, or B1, test flight, says Yahyavi. Programme sources indicate that the Final Gauntlet will be run before the end of January.

Once completed, Boeing will conduct its Flight Readiness Review as part of a comprehensive series of sign-offs by different elements of the programme, including engineering, manufacturing, safety and flight-test teams, followed by low- and high-speed taxi tests ahead of its maiden sortie. This will launch a planned 1,700 flight-test programme that will involve three 747-8Fs and should culminate in certification and first deliveries by the end of 2010.

PRODUCTION

As Boeing prepares to head into flight-testing and certification, production is well under way for the first several 747-8Fs. RC502, the first production 747-8F, underwent power-on activation during the week of 4 January and is parked on the first slant position next to RC522, the third flight-test aircraft.

The road to production has not been without its challenges. Boeing announced on 6 October a $1 billion charge to its quarterly earnings stemming from $640 million in "higher estimated costs to produce 747-8 airplanes at both Boeing and supplier facilities".

The October announcement included a further slip of three months in first flight from the fourth quarter 2009 to early 2010, and a corresponding slide in first delivery from the third to the fourth quarter of 2010. That delay in the freighter followed a November 2008 delay of six to nine months that was attributed to resource starvation from the 787 and a supply chain unable to handle design changes.

The slip was the second major delay in as many years for the freighter programme that has totalled 12-15 months from its original October 2009 delivery date.

Similar delays were incurred by the 747-8I as it shifted first delivery from late 2010 to the fourth quarter of 2011.

While attributable to declining demand for large freighter aircraft, Boeing also grappled with reconciling 40-year-old mylar engineering drawings that have remained consistent throughout the programme with more recent Catia v4 and v5 drawings used for the -400 and -8 improvements to the aircraft.

One veteran programme engineer described the challenge as "trying to bridge the gap between 1969 and 2009".

Everything looked good on paper, says Yahyavi, although with "the mix of mylar and the digital assembly, we found a series of clearances and tolerance issues when we put the structures together in the airframe".

To overcome the challenges of mixed designs, Yahyavi says his team went "drawing by drawing" checking parts through electronic systems for interferences with adjacent parts and brackets so "you can see electronically way up front instead of finding it in the first article".

Yahyavi says that his experience heading the P-8A Poseidon anti-submarine aircraft programme before joining the 747-8 effort in February 2009 helped in applying these lessons, as the 737, on which the Poseidon is based, was derived from new digital designs built on legacy engineering drawings.

Boeing 747-8
© Flightglobal/TimBicheno-Brown 

 

Yahyavi calls this the most important lessons learned on the programme, and is being actively applied to the -8I, which has had 90% of its engineering drawings released to date and 64 consecutive weeks of 100% on-time drawings released as a result of those lessons. Yahyavi says that Boeing plans to begin initial assembly of the first passenger model in May.

Two aircraft will take part in the 747-8I flight-test programme, the first destined for a VIP customer and the second for Lufthansa. First delivery of the -8I is planned for the fourth quarter of 2011 to an undisclosed VIP customer widely believed to be a Middle Eastern head of state.

Boeing is sober about the current state of the freighter market. Cargo traffic was down sharply in 2009, although a modest 7% bounce back in air cargo is forecast for 2010 by the International Air Transport Association.

Guggenheim Aviation Partners revealed on 8 January that it had cancelled two of four 747-8 Freighters on order, signalling further how far the cargo market has yet to rebound to its pre-recession levels.

CHARGE ABSORBED

As a result of the downturn, Boeing has absorbed a $360 million charge, as part of the $1 billion booked in October to "maintain the 747-8 production rate at 1.5 airplanes per month nearly two years longer than previously planned".

Yahyavi believes that the 108 aircraft order backlog, of which 76 are freighters and 32 are -8I passenger or VIP aircraft, will grow as the economy rebounds and the performance of the aircraft is validated over the next year. "I would foresee a pretty good interest in this airplane," he says.

Both airline customers, Lufthansa and Korean Air, have purchased the 747-8I to fit between their 350-seat fleets and 500-seat Airbus A380s. Yahyavi says there are "several others" interested in the aircraft compared with its larger Airbus competitor.

He says it all comes back to "the history of the 747 family...the -200 and -400. You would expect to see some really good movement in the market."

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