Boeing 747-8

Jeannot a écrit:Cet avion est bien mal né

• les problèmes de moteurs
  
• les problèmes de réservoirs
  
• les problèmes de flutter
  

Les chinois ont du avoir un prix canon !

• "with known safety defect" ?
  

Boeing reduces 747-8 weight, tweaks aileron setting

[Vous devez être inscrit et connecté pour voir ce lien] has dropped the empty weight of the latest [Vous devez être inscrit et connecté pour voir ce lien] Freighters by 2.5t compared to the aircraft delivered a year ago and tweaked the aileron configuration to boost aerodynamic performance.

The improvements were revealed at an industry conference on 29 November by a [Vous devez être inscrit et connecté pour voir ce lien] executive, who noted the long-awaited weight reduction arrived with the delivery of the carrier's sixth 747-8F in mid-November.

"Strangely, we're very happy" with the new aircraft's performance, Yves Germeaux said at the Ascend Aviation 2020 Finance Forum, a Flightglobal-sponsored event, in San Francisco.

Cargolux helped Boeing launch the 747-8F with the first order, but then refused to accept delivery of the first 747-8 for several weeks last year due to disputes about contractual guarantees. Another carrier, Atlas Air, cancelled orders for three 747-8Fs last year partly due to performance issues.

But the Luxembourg-based carrier's position appears to have softened with the latest arrival in its fleet.

"The performance, with [the improvements] all in mind, is quite close to what Boeing had in mind," Germeaux added.

In response, Boeing agreed "overall" with the Cargolux assessment of the performance of its sixth 747-8F, but also noted that some customers have reported a 1% fuel burn improvement compared to Boeing's promises.

Boeing has not publicly updated the empty weight specification on the 747-8F since December 2011. At that time, airport planning documents released by the airframer showed the baseline weight had already started decline since first delivery in October 2011, falling by 363kg (800lb) to 190.9t.

At the same time, Boeing increased maximum take-off weight for the 747-8 by 1.3% to 448t, based on the results of a flight loads survey that showed extra payload margin in the airframe.

Since that time, the Freighter model has also benefitted from improvements introduced with the certification of the passenger 747-8 Intercontinental model on 14 December 2011.

Boeing now says that the 747-8I added enhanced positioning of the fly-by-wire outboard aileron in cruise, and that feature was retrofitted on the 747-8F. More improvements are expected to be introduced next year, with the second performance improvement package (PIP 2) of the General Electric GEnx-2b engines.

Boeing To Use 747-8 Dropped By Lufthansa To Complete Test Work

Lufthansa and Boeing have agreed that a 747-8 previously allocated for delivery to the airline will now become a dedicated test aircraft for a set of airframe, system and engine improvements due for delivery in late 2013.

The aircraft, Line Number 1435, first flew in April 2011, but already has been used for some upgrade testing and now will continue in this role rather than be refurbished for Lufthansa. The move, which was triggered by the need to flight test a revised tail fuel system for activation on later aircraft, means that Lufthansa’s 747-8 firm order book backlog is reduced from 20 aircraft to 19, though the airline hints that this may only be a temporary reduction.

Lufthansa still is scheduled to take five 747-8s as planned in 2013, and 10 more aircraft by the end of 2015 that will incorporate the lighter structure and improved systems and engines. The airline currently has four 747-8s in service.

Explaining the decision, the German carrier’s 747-8 chief pilot Elmar Boje says the extensive flight test modifications already made to the aircraft would mean that, even after post-test refurbishment, the unit would be a non-standard “white elephant” in the Lufthansa fleet. However, he adds the airline’s long-range fleet group is due to decide on adding additional aircraft by the third quarter of 2013, some of which could include 747-8s.

Although the decision effectively shrinks Boeing’s total 747-8 backlog to 71, the manufacturer is putting on a brave face because a variety of upgrade testing, including the General Electric GEnx-2B performance improvement package (PIP), can now be bundled into one dedicated certification effort. “The plan was to use a 747-8F freighter for the PIP flight test, but when we de-activated the tail fuel we needed an -8 Intercontinental” to flight test the revised system, says 747 VP and General Manager Elizabeth Lund. “That’s when we started our conversation with Lufthansa.”

The aircraft, originally destined to be Lufthansa’s fifth 747-8, will be used for flight testing throughout 2013 and refurbished for onward sale in 2014 as either a standard airliner or for possible business jet modification.

“Lufthansa opted to take a new aircraft instead in 2014,” says Lund. “So as a result, we had to pull this one out and delay delivery to next year. Lufthansa reserves the right to add another at the end. We asked to use it, and it was already instrumented for tail fuel testing. So all in all it’s a good business decision by them,” she adds.

Improvements to be tested next year are concentrated on the upgraded engine configuration and tail tank fuel system, though the effort also includes updates to the flight management computer (FMC) to incorporate additional required navigation performance features and a “quiet climb” function.

The FMC 3.0 load is scheduled for the end of 2013.

747-8 passenger model’s 3,300 gal. tailplane fuel tank was de-activated before the first aircraft entered service after analysis indicated that, under certain fuel load circumstances, the tail tank could induce flutter.

Re-activation of the tail fuel tank will provide added range and improve the aircraft’s performance, says Lufthansa’s Boje. The extra weight of the fuel in the aft of the aircraft can be used to assist in trimming the 747-8 to lower cruise drag. The 747-8’s fuselage extension “tends to be nose heavy so we might gain performance,” he adds.

Lufthansa also plans to ask Boeing to study minor software changes to the fuel transfer system which would extend the length of time the fuel remains in the aft tank, which would increase the trim benefit.

[Vous devez être inscrit et connecté pour voir ce lien] has formally cancelled a [Vous devez être inscrit et connecté pour voir ce lien] 747-8I order after the manufacturer asked to retain the respective aircraft for internal purposes.

The aircraft in question, RC021, which is registered N6067U, was part of Boeing's three-strong flight-test fleet and used to test cabin systems such as air conditioning, galley and lighting equipment.

It has been furnished with Lufthansa's cabin interior and visited the German carrier's base in Frankfurt in December 2011 for promotional filming work and ground operational tests prior to the first delivery in April.

The aircraft, which is already painted in Lufthansa's basic colour scheme with a [Vous devez être inscrit et connecté pour voir ce lien] fuselage, grey underside and blue vertical stabiliser, was to be delivered as the carrier's fifth 747-8I later in the year.

But Lufthansa revealed during the summer that it would only take four aircraft in 2012. Boeing wanted to keep the aircraft for internal purposes for two years, says the airline, and asked to "relieve" the delivery schedule.

The carrier originally ordered 20 747-8Is, which were to be delivered in batches of five every year through 2015.

Lufthansa says that it has decided, in the meantime, to cancel its order for RC021 "purely due to reasons of flexibility" but that the remaining balance of 15 747-8Is would be delivered as planned until 2015. The airline adds, however, that it might order a "factory-new" 747-8I at a later stage.

Publié le 24 février 2013 à 17h00 par Joël Ricci

Le programme du plus long avion du monde, le 747-8, pèse sur les comptes de Boeing, le constructeur aéronautique américain prévoyant qu’il fabriquera au-delà de 2013 des 747-8 non encore vendus, à cadence maintenue et si aucune autre commande ne parvient d’ici là.

Ce n’est certainement pas le souci majeur de ces derniers mois pour Boeing, mais cela a mérité une note de sa part auprès de la Commission des opérations en Bourse (SEC).

Un certain nombre de 747-8 Intercontinental (747-8I ou version passagers) et Freighter (747-8F version cargo) produits au-delà de 2013, attendront sur le tarmac après leur sortie d’usine, de pouvoir être vendus en raison d’un carnet de commandes plutôt rachitique en comparaison des B777, B737 MAX ou encore les 787, même si ces derniers connaissent leur lot de problèmes encore irrésolus.

Aujourd’hui, Boeing produit deux 747-8 par mois (Freighter et Intercontinental confondus), soit 24 d’ici fin 2013. Or, si le carnet de commandes à honorer s’élève encore à 67 unités (39 747-8F et 28 747-8I), tous ne sont pas livrables cette année. Et le marché en termes de commandes n’est pas attendu à la hausse, les clients ne faisant toujours pas preuve d’empressement. Le programme pourrait donc faire face à des « pertes substantielles supplémentaires ». « Si nous ne sommes pas capables d’obtenir des commandes en 2013 en adéquation avec notre plan de production à court terme, nous pourrions prendre des mesures incluant une réduction du nombre d’avions produits et pour lesquels nous n’avons pas encore reçu de commandes », relate l’avionneur américain.

Aujourd’hui, les seules compagnies à avoir acquis le 747-8I sont Lufthansa (4 livrés et 15 encore livrables), -une de ses filiales Lufthansa, Swiss, réfléchirait à remplacer ses A340-200 vieillissants par des JumbetsJets nouvelle version- Arik Air (2 livrables), Korean Air (5 livrables) ou Air China (5 livrables) plus des VIP (8 livrés et un encore à l’être).

Jusqu’à aujourd’hui, 40 modèles (sur 107 commandes) toutes vers versions confondues ont été livrées dont 28 Freighter.