Maintenance providers expect significant change with the service entry of the Boeing 787. While there is less concern about the technological demands to repair the carbon-fibre airframe structure, many anticipate a shift towards more intensive line maintenance, large capital requirements to establish new MRO capabilities and novel internal processes, such as keeping the aircraft's complex systems software up to date.
Air Berlin is a 787 customer which, after supporting its existing fleet of 737, Airbus A320-family and A330 aircraft in-house, is evaluating whether to give airframe and component maintenance for the new twinjet out of hand and subscribe to Boeing's GoldCare MRO programme. The German carrier has ordered 18 787s, scheduled for delivery from 2014.
Whether this fleet will warrant the investment to build the required capabilities will partly depend on how much additional third-party custom can be attracted to ensure sufficient continuous workflow, says Tobias Hundhausen, vice-president business development.
He says Air Berlin Technik's composite repair capabilities are limited and focus mainly on items which can be repaired in the workshop. In future, he expects more large-scale repairs in the hangar and many more composite repairs. While he is confident small-scale fuselage defects can be fixed with pre-fabricated repair kits, he is unsure how to deal with large-scale damage. "This is an area where we still have information deficits, where we depend on the manufacturer's expertise and which we need to clarify in the coming months," says Hundhausen.
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Logistical concerns
This is echoed by Christian Weckesser, project manager for 787 aircraft engineering at Lufthansa Technik (LHT) in Frankfurt. "With repairs beyond a certain size, we fear that we will quickly get to a point where the SRM [structural repair manual] will not be sufficient and that we then have to talk to Boeing and evaluate the damage together with them. And that will cost time."
Weckesser says he sees no fundamental technical difficulties in repairing composites, given the synthetic fibres and resins have been increasingly moulded into primary airframe structures during past decades, be it floor beams on the 777, vertical and later horizontal stabilisers on Airbus aircraft or complete fuselages for military and business aircraft.
His concern is about the logistics and potentially longer time requirements to bring an aircraft back into service. Expecting large panels will have to be ordered from Boeing, he questions whether material will be as readily available as is the case with metal aircraft.
Boeing responds that airlines and MRO companies will be able to stock composite panels but some materials need to be temperature-controlled and have limited shelf lives. Whether operators and maintenance providers with exposure only to small fleets will invest in repair material, which might have to be discarded unused, remains to be seen.
As an alternative to bonded composite repairs, operators will have the option to undertake bolted repairs with titanium parts. Similar to how metallic airframe structures are fixed using sheet metal, it is possible to fasten titanium patches across a damaged fuselage area as a permanent repair. If a composite solution is preferred, it is possible to remove the metallic fix later on and replace it with a wet composite layup, says Ron Murray, Boeing's 787 chief mechanic.
"We really don't envision major-type repairs other than the usual damages we see on aluminium aircraft today, which can be taken care of with simple materials [prefabricated kits], which the airlines can either have or be readily available from Boeing," he adds.
A major bugbear in supporting the 787 will be to keep systems software up to date, says LHT. Much of the twinjet's equipment and functions are controlled via software. These programs are not installed in self-contained components but run as part of a common core system (CCS), which works as an aircraft-wide computer network.
Software maintenance
Maintaining this system, particularly with updates and modifications, will be a significant challenge. Weckesser says LHT has benefitted from its experiences with the Airbus A380, which also features a network server IT structure, but he adds that this expertise needs to be further intensified because of more software-controlled components and functions on the 787. While the replacement of a component can usually be accomplished quickly, it might not be as easy to install the respective software and ensure full operability, says Dirk Winkler, LHT senior sales executive. "The timescales, which the manufacturers suggest to upload new software, do not always match the reality," he says. "We believe that the aircraft will make the dispatch with MEL-relevant [minimum equipment list] items easier during line maintenance operations. However, we also believe that if we face a non-standard problem, the delays and downtimes may be significantly longer than on current aircraft."
Tracking the software updates and configuration status of individual aircraft across a diverse fleet will be a central task in supporting the 787. This will be further complicated if, for example, an airline contracts separate engineering, line and base maintenance providers which employ individual MRO processes and IT systems.
Software can be uploaded to the 787's computer network by cable connection from a laptop or via wireless link in the airport. Air Berlin wants to stream software wirelessly but to reduce risk of complications it will initially transfer software from a laptop, says Hundhausen. He adds that the choice of connection is only to upload the software on the aircraft's network but the installation will always need to be carried out by an onboard engineer.
For Air France Industries' (AFI) KLM Engineering & Maintenance, a main challenge in servicing the 787 is the high price of components. The Franco-Dutch company wants to offer operators full-support component MRO packages with access to spare-part pools. The investment to set up the inventory, however, might necessitate co-operation with external partners, says to Marcel Roubaud, senior vice-president business development. "We are wondering if we can find some synergies with partners in order to finance the spares needed to provide a good component support."
AFI formed Spairliners with LHT as a component-support venture for the A380. The spare-price issue for the double-decker aircraft was exacerbated by its comparatively small global fleet and limited number of operators. Nevertheless, KLM calculated it needs to have at least 100 787s under contract to achieve savings through scale effects.
The company wants to provide MRO support for the entire aircraft in the long-term, but because of the service periods until the first scheduled overhaul events for the engines and airframe, it will initially focus on components. Avionics and pneumatics are likely to be among the first product areas KLM will develop repair capabilities for.
Technical training will not begin until next year as the equipment will initially be covered by the manufacturers' warranties, says Roubaud. So far, the company has mainly allocated engineering staff to manage the maintenance operations of early customers for the new aircraft.
Component cost
As with previous aircraft generations, manufacturers aim to reduce the maintenance requirements for their new models. Thanks to the carbon-fibre construction, Boeing has been able to double the period until the first airframe overhaul typically from five to six years for metallic aircraft to 12 years on the 787, significantly reducing the need for conventional base-maintenance work.
Nevertheless, none of the MRO providers questioned were concerned about losing custom. Experience with the latest aircraft, such as the A380, has shown their sophisticated equipment will require new support tasks and skills. "Personally, I believe that the efforts for line maintenance will significantly increase and that this will require significantly higher qualifications," says Winkler.
"So we will need more qualified personnel. This cannot be handled by any technician any more," he adds.
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Source: Flight International
