When Emirates last summer towed one of its Airbus A380s into its Dubai MRO facility for a 3C-check – an overhaul scheduled after six years of operation – this was not the type's first such event but marked the beginning of a heavy maintenance cycle for what is, by a wide margin, the largest fleet among operators of the double-decker.
The aircraft (MSN011, registration A6-EDA) was Emirates' first superjumbo, manufactured in 2007 and delivered the following year. The Gulf carrier became the second A380 operator, after the type had been introduced at Singapore Airlines in 2007.
Last summer's overhaul took nearly eight weeks, with technicians working round-the-clock on the aircraft. About 1,600 interior items – including seats, galleys, bars, shower rooms and parts of the cockpit – were removed over a 12-day period. After the equipment was inspected and repaired, or replaced where necessary, the reinstallation required two weeks. Meanwhile, technicians inspected the airframe and conducted repairs and modifications. Two engine pylons of the Engine Alliance GP7200-powered aircraft were also removed during the hangar visit.
Future A380 3C-checks may require more than the 55-day ground time needed for the initial overhaul, as they are set to include additional heavy structural modifications such as work on flap tracks and leading edges, says Iain Lachlan, senior vice-president of Emirates' engineering division. Maintaining the A380 is a "very labour-extensive" undertaking due to the aircraft's size and requires a large team of technicians and significant investment in special equipment such as tooling, hangar installations and ground support gear, he adds.
This is underlined by Air France's director for Airbus fleet engineering and maintenance Stephane Trigona, who says that servicing the double-deck cabin is a challenge in its own right: "We have to correct more issues sometimes in the same transient check time as for other aircraft like the [Airbus] A330 and [Boeing] 777, because we don't have twice as much time. [The A380] requires some dedicated resources."
Maintenance tasks that can be completed on the ramp for smaller aircraft – such as replacing a rudder servo-control actuator – need to be conducted in a hangar with appropriate support equipment to handle the superjumbo's large components, says Air France A380 fleet manager Pascal Menegat. This makes the aircraft's support more dependent on dedicated facilities than other, smaller types. Due to the limited fleet size and number of operators, this may be further aggravated by the fact that appropriate maintenance capabilities and facilities are less widespread than for more commonly used types.
With much of the A380's systems and components being controlled by software via an integrated computer network, maintaining that infrastructure is a critical task. "The A380 was a real step [change] in technology compared to other aircraft we maintain," says Air France's Trigona. Operators needed to develop new IT capabilities and processes to keep the software up to date and in good working order. "You have more than 700 software [modules] on the A380," adds Menegat, "but they can be fitted on nearly 1,500 positions on the aircraft. So you just cannot manage that on an Excel table, you need a robust tool."
Dirk Meyer, duty manager for A380 maintenance at Lufthansa Technik in Frankfurt, notes that "even simple components which we used to take out of the warehouse and install on aircraft in the past require software on the A380". Aside from learning to handle the software and load it on to the aircraft, secure transfer channels for the programmes between Airbus and A380 operators also had to be established, he says.
Especially during the early operational phase, spurious fault messages from the aircraft's condition monitoring system led to flight delays and lower dispatch reliability than planned. Many of the issues have subsequently been solved with software updates, modifications and increasing experience with the aircraft. However, handling fault messages and troubleshooting the cause behind them is a challenge, says Ma Xiao, engineer at Chinese maintenance provider Ameco Beijing. While the high integration level of the aircraft's network architecture provides a wide range of functionality and convenience, it can lead to "slight unsteadiness and sensitivity sometimes", he says. "One wrong step [in a task] sequence or one failure can cause unpredictable messages. It increases the difficulty of troubleshooting when the technicians are not experienced on this aircraft type."
Further complicating A380 maintenance are repairs to the Glare airframe structure in the upper fuselage area. While repairs of the aluminium-fibreglass composite material require curing periods not necessary for metal repairs, the damage limits of the novel material are "much smaller" than for conventional airframe structures, says Lufthansa Technik's Meyer.
Furthermore, if the airframe has been damaged by birdstrikes or impact from airport service vehicles, for example, the fix will involve a reinforcement of the area in question, bolted on top of the existing structure. Some such solutions could be replaced by finer repairs that are flush with the fuselage skin during subsequent base maintenance events. However, Meyer says accomplishing such structural repairs are much more intensive on the A380 than on older aircraft.
Emirates is "starting to see" Airbus's technical dispatch reliability target of 98.5% on a regular basis, says Lachlan, while less than 2% of Lufthansa's A380 flights are delayed more than 5min, and the flight cancellation rate due to technical issues is "significantly below 1%" today, says Meyer.
The German carrier benefitted from other airlines' experiences when it became the fifth A380 operator in 2010. But Meyer argues that Lufthansa's comparatively "high" reliability rates were partly a result of maintaining the A380 with an approximately 120-strong team exclusively focusing on the type, as the aircraft has a "different philosophy" to other models in the Star Alliance airline's fleet.
Aside from Airbus's ongoing programme of wing-rib fixes, the extent of modifications on the A380 has been at a "normal level" compared with other new aircraft, says Meyer. Similarly, Emirates' Lachlan says that while implementation of a "significant number" of service bulletins has led to a "step increase" in reliability, "the A380 is no different to other aircraft" where modifications are concerned.
Air France expects its dispatch reliability to improve and maintenance operations to become more settled after the implementation of several modifications during its first round of heavy checks. Its initial 3C-check is scheduled to begin by year-end, but Trigona says it is not yet clear where the work will be completed. The airline's MRO arm has conducted A- and C-checks at its facility at Paris Charles de Gaulle airport, but 2C-checks on at least two Air France A380s have been completed at Lufthansa Technik's site in the Philippine capital Manila (LTP). Trigona concedes that "we may not be as competitive as other operators [for labour-intensive airframe MRO] outside Europe where the cost of human resource is much lower".
Air France and Emirates have successively handed their A380s over to Airbus to manage the wing-rib modification programme through external MRO providers. Half of Air France's 10-strong fleet has been modified, with three more aircraft due to be processed in the first quarter of this year, says Trigona. The modification programme does not affect the remaining two A380s, which were built in 2013 and 2014.
Qantas employed its maintenance provider LTP for the modification.
Lufthansa conducted the programme in-house, completing work on the tenth aircraft from its 12-strong fleet last September. The other two do not require the modification. Meyer says the technical team went through a learning curve for the extensive programme, which involves removing fuel system components throughout the wing. "But by the third or fourth aircraft we were able to under-match significantly the timeframe predetermined by the OEM and modify our aircraft in a short time," he says.
The next large modification programme will address an issue with the passenger doors. The vibrations of an exterior Kevlar-made cover plate at the top of the door – caused by the air stream across the fuselage – have led to cracks in the door structure, resulting in a cabin decompression event on board a Singapore Airlines A380 a year ago, with the aircraft diverting to Azerbaijan's capital Baku.
Meyer expects a modification programme with a "very large" work volume, which is likely to start as part of Lufthansa's first 3C-check – scheduled during the winter 2015/2016 timetable. The fix involves reinforcement of the door structure, but Meyer adds that "modifying 16 doors is not quite so easy".
Meanwhile, two of Emirates' aircraft have successively completed the programme. Lachlan says two external MRO providers are conducting the work, with the maintenance taking about 16 days per aircraft through a programme managed by Airbus, similar to the wing-rib fix. "Now we have got another 51 to do!” he adds.
Source: Cirium Dashboard
