Airframer does not expect additional certification requirements despite stretch variant being 10% larger than -400
Boeing is confident it will be able to avoid potential approval pitfalls for its new 747-8 family - increased separation distances and an evacuation demonstration - by leveraging from existing models.
The International Civil Aviation Organisation has introduced new separation distances for the Airbus A380 that are greater than the current "heavy" category, which applies to large aircraft up to the size of the 747-400. With the new 747-8 family being around 10% larger than the 747-400, there has been speculation that the new model could also be required to adopt increased separations, but Boeing believes this is unlikely.
"Our assessment is that [the 747-8's wake qualities] will be pretty similar to the 747-400's," says Dan Mooney, vice-president 747/747-8 programme. "We will likely have to do some validation flights, but we don't expect separation distances to be any greater."
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Boeing expects the 747-8's wake to be similar to the -400's |
Mooney says the 747-8 incorporates a modified version of the 747-400's wing, with key changes comprising a new advanced aerofoil, increased span through the introduction of waked wingtips, and revised high-lift devices. Other than the 5.6m (18ft) fuselage stretch, the main change is the installation of the General Electric GEnx-2B engine, which has a significantly larger fan diameter than engines on the existing 747-400.
Meanwhile, Mooney believes Boeing will avoid having to undertake a full evacuation demonstration despite the European Aviation Safety Agency telling Flight International earlier this year it will request such a test when it meets the US Federal Aviation Administration this month to discuss the certification of the 747-8I.
"We're not going to certify the 747-8 for any more passengers, so we don't think we have to demonstrate it," says Mooney. He adds that the 747's current exit limit, based on a demonstration in the 1970s and then extrapolation for later variants, stands at 660 passengers - around 190 more than the 467 seats Boeing quotes as the 747-8's typical three-class accommodation.
Source: Flight International
