Wednesday, October 1, 2014

A350 certified; we provide a comprehensive program review

Airbus’ most recent all-new aircraft, the A350 has achieved civil airline airworthiness certification from EASA today September 30, FAA certification will follow. It marks an end to an eight year program to develop an all-new airliner in the 250-350 passenger segment. It also creates a point where a review of this last (for quite a while) big aircraft program is called for.

Airbus photo of A350 test aircraft in formation, celebrating the certification.

Airbus photo of A350 test aircraft in formation, celebrating the certification.

Below we go through all the aspects of the A350, not only program and technical aspects but also organizational, economical and market communication aspects. In all those dimensions it was the big step forward.

The first incarnation of the A350 was conceived as a response to Boeings 787 during summer 2004, initially as a revamped A330 (very much like today’s A330neo) and then finally as a re-winged, re-engined A350, very similar in its changes to today’s 777X.

Airbus slide from 2005 showing the main data for the then A350

Airbus slide from 2005 showing the main data for the then A350.

When the program started in its final iteration at the Farnborough Air Show in 2006, 53% of the airframe and wings were composites. The concept had been stretched from an eight abreast design to nine abreast, then called A350 XWB for extra wide body. Final industrial launch was 1 December 2006.

A350 XWB design
The XWB variant did away with the A330 fuselage cross section and introduced a carbon fiber re-enforced plastic (CFRP) fuselage which now had a 0,35m or 14 inches wider cabin to enable nine abreast seating with 18 inch seats. Much has been made about the A350 fuselage now being made of large panels, which has four longitudinal joins for the panels to form a barrel section. The competing Boeing 787 was made with shorter barrels which were only joined circumferentially. This is probably the difference between the design that has the least operational and technical influence between the aircraft. They are both CFRP based fuselages which enable higher cabin pressure and humidity for passenger comfort and reduced maintenance requirements as CFRP is virtually fatigue and corrosion immune.

Main features of A350, taken from a June 2014 Airbus presentation

Main features of A350, taken from a June 2014 Airbus presentation.

The A350 and the 787 share many design solutions, such as CFRP based structure, wing design with high lift arrangement (cooperating spoilers and flaps for simple and effective high lift trailing edge, adaptive wing for optimal cruise lift versus drag ratio and load alleviation) and way of attaching the main landing gear by means of a Y spar arrangement on the inner trailing edge (the so-called Yehudi). They also have similar avionics concepts, based on networks of computing nodes connected with an adapted Ethernet network (AFDX).

The biggest difference between the A350 and the 787 is the way they deliverer power to the aircraft’s different systems. Boeing decided 2003 that it was time to go for an all electrical power conversion chain from the engine source to the power consuming system whereas Airbus decided to stay with a conventional system (inherited from the A380) which split the power delivery between an electrical conversion chain and a pneumatic one. While Airbus could migrate a modern classical system and its vendors to the requirements of the A350, Boeing had to start from scratch, architecting numerous firsts in the process such as water-cooled conversion electronics in an extra equipment bay behind the main landing gear bay. New designs from scratch means new challenges and Boeing had its share of operational problems with the more electrical systems architecture (conversion panel short-circuits, battery problems….). The all electrical architecture also means higher requirements on auxiliary power, the high electrical requirements of the 787 have made more than one airport power aggregate look bleak.

In contrast, the A350 system side has been smooth sailing with a high system maturity evident in the unusually trouble-free flight test period. This should also give initial airliner service an easier start. Once through the initial problems the more efficient power conversion of an electrical system should gain the 787 a slight efficiency advantage on the system side. In retrospect Boeing probably ask itself if it was worth all the hard lessons.

The A350 continues the Airbus tradition of a Fly-By-Wire aircraft with a family look-and-use cockpit (including side-stick), enabling an aircraft characteristics and cockpit commonality which has reduced aircrew cross-certification requirements since the A320. The Fly-By-Wire system is now in its fourth major revision with the signaling to the rudders going full digital; its maturity and adaptability has been obvious. We met with some of the A350 test pilots at Farnborough and they all said the A350 was very similar to an A330 to fly and the flight testing of the base characteristics of the aircraft had been virtually trouble-free.

System and Flight testing
Airbus has had the advantage to work with mature system concepts and their retained suppliers from previous programs. While all components have been brought up to date there has been no major architectural change in critical systems like flight control, power distribution, hydraulics, air conditioning etc. This has laid the foundation for a system and flight test that could focus on system maturity at EIS instead of getting the systems to work correctly. The final flight testing had been preceded by an extensive system test of individual components up to complete system rigs. But even before A350 hardware was available the correct functioning and interaction of all the myriad of system had been tested with digital models simulating the interaction of all critical systems.

As a consequence of all these preparations flight testing has been unusually trouble-free. The flight test team recognized they got an unusually mature aircraft when preparing for the 14 June 2013 first flight. This impression has since not changed. The aircraft has gone through flight testing without any major findings, allowing Airbus to stick to the 3Q2014 certification schedule set after previous development delays.

Program management
Airbus had major deficiencies in the program management of its previous program, the A380. The company was still suffering from having been a consortium of independent national companies, each convinced that they knew best how to design and produce their part, to the extent that they even reserved the right to have their own tools (the famous Catia version 4 to version 5 incompatibility between the German and the French parts being only the tip of the iceberg). Lessons learned from the A380 (and from observing the tortured development of the Boeing 787) were applied to the A350 program, not in the least in the company structure and program management. The company was galvanized into one by several restructuring programs (Power8, Future EADS) and program management was reinforced.

The A350 program manager, Didier Evrard, reported to the COO, Fabrice Brégier, and when Brégier was elected CEO, Evrard moved up as well in the corporate structure. Evrard thereby had the position to escalate any resource conflict or hold-up in the company. Further lessons learned were drawn from the troubled A380 program. All parts of the company were forced to work on the same toolset (the main being the product lifecycle management system, Windchill, and the 3D design tool, CATIA). Strict rules were introduced where every engineer and partner (in total 5,000 people including 60 partners) had to manifest every change of a design in the gigantic Windchill database. Catia was then used to visualize in 3D any changes in the design of the aircraft in real time. This visual mode, which is constantly updated to stay current, is called DMU (Digital Mock Up). The realtime DMU meant there was only one copy of the virtual A350 and one could rely on all the data in the database being current. This was a big change from the A380 where multiple copies of the aircraft were being worked on in the different countries and no-one knew which model was up to date and if so in what part of the model.

Another area which was given much attention was program management rules. In earlier projects, should, for instance, a part of the flap system not be finished for a critical design review, one could still let the wing pass the review and let the failing part catch up on a side-track to the main design. This rule, to keep the time plan and fix later, lead to the traveled work on the A380 and 787. It meant that work was being done by persons other than those who should normally handle the matter, requiring re-learning for these persons once the traveled work package was closed. It created inefficiencies and that knowledge was built up in the wrong hands. When finally the part was to be installed, one often had to disassemble the aircraft first as the part was now out of sequence. Further, the original tasks that should have been performed on the parts removed now had to wait until things are reassembled. Finally the knowledge had to be transferred to those in the production chain who should normally handle the task. Airbus changes this to the principle of “Stop and Fix” for the A350. It is better to take a delay immediately than later. This ensured that whatever problem caused the part to not meet the deadline the fix was worked on by the relevant persons or groups. It also builds the pre-production competence in the right places. This principle was also extended to production. Airbus was extremely cautious in the ramp of the test aircraft and later the first production aircraft, with the benefit of not having (too many) parts out of sequence.

The principle of “stop and fix” could be seen in work in the early parts of the program. The new composite construction caused some new problems to solve. CFRP parts don’t conduct electricity so an extra layer of metal mesh had to be introduced to serve as a lightning conduction part and as an electrical return path. The design of this rather complex “electrical structural network” took longer than planned. Another aspect of CFRP is that it is very strong in the fiber’s long axis but not in the traverse axis. Consequently a lot of work and testing had to be done on the so called “damage tolerance” of the aircraft’s skins. The strength of CFRP allows these skins to be very thin in places but the normal bumping into the aircraft by ground vehicles, docking for catering or cargo loading, could cause non-visible damage to the layered matrix. Hence the CFRP material thickness had to be increased beyond what was required from a structural point, as this adds weight the investigations into just how much were important and these took longer then planned.

The effects can be seen in the schedule graph which is a cut from Airbus presentations in early 2010 and late 2011. By 2010 these delays had eaten up all margins and the subsequent discovery of other issues lead to the rescheduling of the whole program, first to mid 2014 delivery, then finally to “second half of 2014”.

Airbus publicized program schedules from early 2010 and late 2011

Airbus publicized program schedules from early 2010 and late 2011.

These are just examples of the myriad of causes that forced Airbus to delay the program first by a year and then finally by 18 months. The effect of this principle was the there were delays in the initial and mid-part of the program. Once the necessary maturity had been reached for the different parts and systems, the time-plan stabilized and the test period was one of the smoothest ever. There has been no further delay since summer 2013.

Program communication
The A350 program has also broken new ground in how communication has been handled. Initially the communication tone was “we will not be delayed like the 787” i.e. a self-assured style like its competitor, with exact milestones that would not be touched. When it was seen that delays were inevitable, the communication tone changed and became more understated and cautious. Milestones were always given as “second half of 2013” rather than exact and it was always stressed that the program was very challenging.

Nowhere was the communication more elegantly handled then around the considerable weight creep the program experienced. All-in–all, the Operating Empty Weight increase from launch to EIS was in the region of 6%-7% compared with 12% for the weight-troubled 787-8. Boeing subsequently got that down to 9%. Where the outcry re the 787 weight creep was massive, it was virtually non-existent for the A350. Airbus waited with all hints of major weight changes until flight testing had shown exactly where they were, then the range was quietly cut with 350 nautical miles despite a change to a lighter two class interior of 315 seats (instead of the original 314 seat 3-class interior) and the addition of a maximum MTOW variant that raised MTOW from 268t to 275t. The few that noticed the range changes were told that if was indeed no specification change, the cabin had changed and so did the range. These changes represent more than an hour’s worth of fuel but few seems to have noticed (other than Leeham News, which reported it at the time). There has been no media attention on this blip. (The customers have, of course, known all the time; the only one who has been vocal about it is Emirates Airlines, which canceled their order for this reason among others).

This media strategy has rendered Airbus a lot of good will, to the degree that when slip up occur it does not have much news value.

Entry into service and production ramp
The challenge now for Airbus is the first customer’s experience of the aircraft’s reliability and how Airbus can manage the ramp up of production. Perhaps unfortunately for Airbus, the first operator will be Qatar Airways, whose CEO, the mercurial Akbar Al-Baker, isn’t the least bit shy about criticizing any of the OEMs on real and perceived shortcomings, often doing so publicly.

To ensure a high degree of visibility on the operationional maturity problems that can occur, the Airbus flight test operation worked as Airline number 1, i.e. all operational routines, etc. has been carried out as if the flight test was an airline operating the five test aircrafts. This has made it possible for Airbus to identify any problem areas that might not come up in traditional flight testing where aircrafts are fixed for glitches directly by the development organization.

Graph of "Airline 1" organization from Airbus June 2014 presentation

Graph of “Airline 1″ organization from Airbus June 2014 presentation.

We have carefully monitored the production during recent years. The flight test aircraft had slips in their entry into service of typically 1-2 months over of what was originally presented. For the customer deliveries we see the chance of two aircraft delivered to Qatar this year and for a further six Qatar deliveries first Quarter 2015. This is enabled by the FAL start curve we see below presented by Airbus at the innovation days in June, the rate, presently at two starts per month, goes to three starts per month end of this year and these aircraft will be delivered end Q2 2015.

Final Assembly ramp of production taken from June 2014 Airbus presentation

Final Assembly ramp of production taken from June 2014 Airbus presentation.

Production time is around 8.5 calendar months for the first aircraft, then gradually reducing to seven months for deliveries in Q1 2015 and six months by next summer. Airbus has made several expansions in the production facilities in Toulouse and right now we see no reason that they should not deliver to their latest communicated plan.

A350-800 and -1000
The A350 is the latest in a range of clean sheet designs by the large OEMs (A380, 787, A350). Its fortunes will decide Airbus’ market share in the profitable large twin widebody segment. The smallest variant was officially canceled last week by CEO Brégier, its place being taken by the A330neo. This leaves the A350 production system free to focus on the above 300 seat segment where we are now waiting for its larger variant, the -1000. Programmed for mid-2017 EIS, its fortunes will be decided by how Airbus can control the weight increase versus the A350-900, right now by 10-13 tonnes. Its position was comfortable when the competition was the heavy and under-winged Boeing 777-300ER. This has all changed since Dubai Airshow last year where Boeing launched its answer to the A350-1000, the 777-8X and -9X. The -9X is especially troublesome for Airbus as it flies more passengers further at about the same seat cost as the A350-1000. For an airline that does not need the capacity, the A350-1000 is a safer choice with considerably lower trip costs. Should the airline need more capacity, the A350-1000 is pressed. We expect an answer from Airbus in the 400 seat segment in the coming years.

Summary
The A350 had a troubled birth, an initial development that generated delays and then a final two years where everything has gone to plan. The initial development tactic of accepting delays to build maturity in the design has paid off. The next phase of the A350 program will be no less interesting then the first, to follow the induction into service; it has potential to set new benchmarks for modern clean-sheet designs.

By Leeham Co EU


Filed under: Airbus, Boeing Tagged: A350, Airbus, Boeing, Rolls-Royce
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