tag:theconversation.com,2011:/africa/topics/a380-2289/articlesA380 – The Conversation2019-02-19T15:29:00Ztag:theconversation.com,2011:article/1120862019-02-19T15:29:00Z2019-02-19T15:29:00ZAirbus A380: from high-tech marvel to commercial flop<figure><img src="https://images.theconversation.com/files/259728/original/file-20190219-43273-w16gs4.jpg?ixlib=rb-1.1.0&rect=0%2C26%2C968%2C592&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The final deliveries of the A380 are anticipated for 2021.</span> <span class="attribution"><span class="source">Mike Fuchslocher/Shutterstock</span></span></figcaption></figure><p>This time it really is over. Airbus chief executive, Tom Enders, recently announced the <a href="https://www.youtube.com/watch?v=6T4nijoSdyk">end of the A380</a>, the largest commercial aircraft ever built. Despite reported investments of more than <a href="https://www.bloomberg.com/news/articles/2015-04-26/airbus-a380-haunted-by-lack-of-orders-marks-decade-in-the-skies">€14 billion</a>, this iconic European project has not been as successful as was originally hoped. With only <a href="https://www.airbus.com/aircraft/market/orders-deliveries.html">234 units delivered out of 313 ordered</a> over 13 years, it is far from the break-even point – originally estimated at 1,200 aircraft over 20 years. With orders drying up and production already running at a minimum, it was time for Airbus to stop the damage.</p>
<p>Long before its launch date, the A380 appeared to represent the future of Airbus, which anticipated that <a href="https://www.cnbc.com/id/16882170">air traffic would double in the next 20 years</a>. That’s why it is both big – it can carry anywhere from 550 to more than 800 passengers on two full decks – and luxurious, with options such as private rooms, restaurants and bars – even an <a href="https://www.dailymail.co.uk/travel/travel_news/article-6700789/The-amazing-story-A380-told-incredible-pictures.html">in-flight casino</a>. Its engines are on average <a href="https://www.rolls-royce.com/products-and-services/civil-aerospace/airlines/trent-900.aspx">30% more powerful than those of the Boeing 747</a> and are worth €13 million each – the value of a ton of gold for all four.</p>
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<figcaption><span class="caption">National Geographic dedicated an episode of its series ‘Megastructures’ to the A380.</span></figcaption>
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<p>To keep the overall weight down, the A380’s designers used <a href="https://www.ingenia.org.uk/Ingenia/Articles/b48c6ee4-965a-4a55-a3fc-b8c2619fa6ec">groundbreaking composite structure</a>, including carbon ribs within aluminium wings. Equipped with the most advanced navigation system in commercial aviation, it can operate for more than 13 hours and fly more than 9,000 miles. </p>
<p>The aircraft is built on a continental scale: the wings are made in Wales, engines are made in England (Rolls Royce) or the US (Engine Alliance), the fuselage and the vertical stabiliser is built in Germany and the horizontal stabiliser in Spain. Final assembly is carried out in France. Each wing weighs 6.5 tons and is composed of <a href="https://captaindave.aero/2017/09/02/the-a380-wing-a-complex-work-of-art/">tens of thousands of components</a>, carrying the fuel, supporting the fuselage and channelling the power of the engines.</p>
<h2>Niche market</h2>
<p>If the A380 is undeniably one of the most impressive aircraft of all time, its unique design and distributed production system created numerous <a href="https://books.google.fr/books?hl=fr&lr=&id=KcaYjPhRnWUC&oi=fnd&pg=PA6&dq=A380+program+cost&ots=rmv403X072&sig=Yst8-nwpx2dv8bZs2hSjEj6S9wM#v=onepage&q=A380%20program%20cost&f=false">technical and coordination problems</a>. The initial launch was delayed 18 months by a range of difficulties, and the ability of airlines to customise the aircraft proved to be an additional source of delays. </p>
<p>While the A380’s first flight – on April 7 2005 – was a success, the market was already changing. Airlines that initially favoured big hubs such as <a href="https://www.sciencedirect.com/science/article/abs/pii/S0969699708000963">Singapore and Dubai</a> began to offer more direct flights from a significant number of middle-sized airports. The rise of low-cost airlines brought in influential new players and weakening the long-time leaders that had been seen as big prospects for the A380.</p>
<p>Most importantly, the 2008 economic crisis seriously cut into the growth in air traffic. <a href="https://skift.com/2018/09/14/10-years-later-how-the-travel-industry-came-back-from-the-financial-crisis/">While growth has returned</a>, the market is smaller than expected, making it harder to fill a wide-body aircraft, much less a double-deck one. It is simply not profitable for an airline to have flights with less than 80% of the seats filled. Emirates, which owns half of all operating A380s, has the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0969699711000160">financial resources to take on this risk</a>, but not other carriers.</p>
<p>It was Airbus’ mimicry of its historic competitor, Boeing, that led to the gap between supply and a considerably evolved demand. While some experts claimed that the A380 was 10 to 20 years ahead of the market, Airbus executives now admit that the plane was <a href="https://www.youtube.com/watch?time_continue=7&v=5rh1Jj8P9t8">10 years too late</a>. As Enders said when announcing the A380’s demise: “What we are seeing here is the end of the large four-engine aircraft.”</p>
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<figcaption><span class="caption">Airbus CEO Tom Enders on the decision to end the A380’s production (AeronewsTV).</span></figcaption>
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<p>With A380 sales lagging, Airbus launched its new mid-size flagship, <a href="https://www.airbus.com/aircraft/passenger-aircraft/a350xwb-family/a350-900.html">the A350</a>, in 2014. It and Boeing’s 787 Dreamliner, both of which have only two engines yet can fly great distances, were preferred because they had <a href="https://edition.cnn.com/travel/article/ultra-long-haul-planes/index.html">lower costs and fewer constraints</a> than the A380.</p>
<p>A380 orders started to dry up in 2015 and persistent rumours suggested that the end was near. There were no orders from US carriers, few in Asia and even Air France <a href="https://www.forbes.com/sites/michaelgoldstein/2018/11/27/if-air-france-no-longer-wants-the-airbus-a380-will-anyone/">halved its anticipated A380 fleet</a>. On January 15 2018, John Leahy, Airbus’ chief commercial officer, declared that if Emirates didn’t order at least 30 more A380s, it wouldn’t be possible to <a href="https://www.forbes.com/sites/michaelgoldstein/2018/01/17/does-anyone-really-need-the-airbus-a380/#7c7237f27eb1">keep the program alive</a>. British Airways, which owns a dozen A380s, has suggested that it could acquire others, but only if Airbus was <a href="https://thepointsguy.com/news/ba-could-save-the-a380-program/">“aggressive on the pricing”</a>. Whatever the result of those discussions, they are unlikely to alter the company’s decision.</p>
<h2>An inevitable disaster?</h2>
<p>Today, the very design of the A380 is being questioned – that it was in many ways a delusion of grandeur by Airbus, which wanted at all costs to <a href="https://www.cnbc.com/id/49974666">beat the Boeing 747</a>. But its four engines consumed too much fuel, and being able to carry more passengers wasn’t enough to make up the difference. The A380’s immense size and double-deck layout also require airport investments <a href="https://www.ingentaconnect.com/content/lse/jtep/2005/00000039/00000003/art00006">not needed for other airliners</a>. </p>
<p>Without the support of Emirates, which has made the A380 its flagship and is probably the only company that will regret its end, the decision to cease production would have been made a long time ago. Emirates has agreed to convert part of its latest order to <a href="https://www.airbus.com/newsroom/press-releases/en/2019/02/airbus-and-emirates-reach-agreement-on-a380-fleet--sign-new-widebody-orders.html">A330neo and A350 aircraft</a>, remaining faithful to Airbus. The last delivery is scheduled for 2021 and there will be no new versions brought into service. Meanwhile, the <a href="https://www.bbc.com/news/av/uk-england-london-43009119/celebrating-50-years-of-the-boeing-747">Boeing 747 celebrates 50 years of service</a> – though it too is ending production, <a href="https://www.flightglobal.com/news/articles/boeing-747s-production-run-could-outlast-a380s-455772/">marking the end of an era for airline behemoths</a>.</p>
<p>The end of the A380 is not necessarily good news for Boeing: it releases Airbus from a weight that has long prevented it from <a href="https://www.researchgate.net/publication/265787531_Competition_evolves_to_simplicity_The_strategies_for_the_conquer_of_the_skies_and_the_announced_battle_between_the_Airbus_A380_and_the_Boeing_777">delivering its full potential</a>. Resources and skills can be better allocated and thousands of workers may be offered jobs on <a href="https://www.theguardian.com/business/2019/feb/14/a380-airbus-to-end-production-of-superjumbo">other production lines</a>. If the end of the A380 is a hard blow, the end of the story has yet to be written for Airbus.</p><img src="https://counter.theconversation.com/content/112086/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Oihab Allal-Chérif ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>The shifting market for air travel has forced Airbus to abandon the production of one of the most impressive aircraft of all time, the super-jumbo A380. Was it folly, bad luck or both?Oihab Allal-Chérif, Full Professor, Information Systems and Purchasing Management, Neoma Business SchoolLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/519582016-01-04T10:43:23Z2016-01-04T10:43:23ZBig is beautiful: why the A380 could still have a bright future<p>The Airbus A380 is a marvel of technology; a majestic aircraft. It is beloved by passengers and it also is an environmental asset for airlines operating out of airports in built-up areas such as Heathrow with its low noise signature. But no new A380 order was taken in 2015 – and the current order book stands at 317 units, with the cost break-even point for Airbus now believed to be standing at as high as 420 units (from 270 initially) as a result of delays in production and detrimental currency fluctuations between the euro and the US dollar.</p>
<p>The A380 is heir and rival to the Boeing 747 jumbo jet in the so-called Very Large Aircraft (VLA) family, for which the maximum combined market size is believed to be between 700 and <a href="http://aviationweek.com/commercial-aviation/opinion-mega-transports-hobbled-their-size">1,700 aircraft</a>. This aircraft is built to capitalise on an air transport model that is based on large “hub” airports. </p>
<p>In such a model it is expected that aircraft such as the A380 would ferry a large number of customers at once thereby helping reduce airport congestion in the process. But the dispersion of routes and traffic and greater competition between carriers means the so called “<a href="http://blogs.cornell.edu/info2040/2011/09/14/hub-and-spoke-vs-point-to-point-transport-networks/">point-to-point</a>” model of air travel is growing more rapidly, at the expense of the hub-and-spoke model.</p>
<p>This also poses the issue of capacity on some routes. Though large carriers such as British Airways have been able to replace three daily Boeing 777 flights from London to Los Angeles with two A380 flights, some destinations simply do not carry the capacity required to successfully deploy the A380. Combined with the dispersion of the routes, this challenges the raison d’être of the aircraft.</p>
<p>Where the A380 was meant to deliver a significant reduction in fuel burn and cost efficiency, the figures that are reached – <a href="http://airinsight.com/2015/11/20/the-a380s-future/">while nearly half that for the 747</a> – are on a par with those of the most successful twin-engine airliners currently on the market. More twin-engine aircraft also provide greater flexibility for airlines. The Boeing 777, and the 777-300ER in particular, have proven particularly successful and this trend is being continued by the 787 Dreamliner.</p>
<p>Perversely maybe, the current low cost of fuel means that in spite of ever greater appetite to fly and a need for competitive ticket pricing, it is currently economical to keep using older aircraft, when taking the cost of acquisition or leasing into account. Air France is only just retiring old Boeing 747s now (the last scheduled flight, AF747, takes place in January 2016). </p>
<p>As most of its 42 747-400s were built in the early 1990s, British Airways still seems to plan a further ten-year service life before retiring them. British Airways has 11 A380s in service today, from a total order book of 12 to date. </p>
<p>Airbus is refreshing its twin-engine offering and compete very seriously against Boeing and its ground-breaking 777 and more recent 787, with the new A350. The aircraft appears to be very competitive and is already taking on the 787. As of end of November 2015 the order book for the A350 showed 775 orders. Based on figures updated in early December 2015, the orders for the 787 Dreamliner stand at 1,142.</p>
<p>Both A350 and 787 are technologically more advanced than the A380 – one indicator can be taken to be the amount of electrical power on the Dreamliner. This shows a step change in aircraft design and the move towards a <a href="http://www.moreelectricaircraft.com/">More Electric Aircraft</a> (MEA), with the flexibility and economy that this offers in service. </p>
<p>Is it therefore possibly the case that the A380 missed its window and came too late or was designed to satisfy a market that is small and an air travel model that has shifted?</p>
<h2>Fighting the naysayers</h2>
<p>The A380 still has its champions; starting with <a href="http://atwonline.com/interviews-video-print/interview-emirates-airline-president-tim-clark">Emirates and its CEO and president, Tim Clark</a>. Emirates is bringing the A380 to a number of so-called secondary and tertiary airports and routes. Clark is fighting the nay-sayers and showing that the A380 works for his company and should be attractive to others. This clearly indicates that the issue is complex and not simply technological but probably financial and commercial too. </p>
<p>While Emirates owns the largest fleet of A380s in the world (it has 67 and is committed to acquiring a further 73) it has also cancelled its order for 70 A350s and Clark has been a vocal proponent for a re-engining of the A380, inviting others, including Qatar Airways and Singapore Airlines, to get behind an A380neo (new engine option). <a href="http://airwaysnews.com/blog/2015/11/13/the-a380neo-no-one-seems-to-want/">The case for an A380neo is heavily disputed</a>, not least because reliance on one customer (Emirates), even for 100 new aircraft, does not make for the strongest business case in light of the investment required. </p>
<p>However, it seems that such support may have <a href="https://www.flightglobal.com/news/articles/dubai-case-for-a380-is-inevitable-leahy-418884/">rekindled Airbus’ spirits</a> to continue with the A380, when it may have been considering the aircraft’s future. Clark sees it as a moneymaking plane and hopes for a further reduction in operational costs of up to 10% with the neo. For him the A380 is a serious and competitive proposition.</p>
<p>With the successful entry-into-service of the A350, the commercial achievements of other aircraft such as the A330 and the commitments of customers such as Emirates to the A380, Airbus may well be sitting on a unique product for the future. Some airlines, such as Virgin Atlantic, are still deferring their decision on the A380 but, should they consider a new very large aircraft in the future, to replace its 747 fleet for example, Airbus would be in a unique position of strength.</p>
<p>The A380 remains a magnificent technological and environmental achievement, the full commercial value of which is yet unclear but is far from written off. And I, personally, remain excited as ever when I see a low flying A380 – such a gentle, quiet and agile giant.</p><img src="https://counter.theconversation.com/content/51958/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Herve Morvan is affiliated with the Midlands Aerospace Alliance and sits on the Special Advisory Group (Propulsion) for the ATI. He is also a key member of one of Rolls-Royce's University Technology Centres.</span></em></p>Demand for the A380 appears to have stalled, but it’s still the best Very Large Aircraft out there.Herve Morvan, Professor in Applied Fluid Mechanics and Director, Institute for Aerospace Technology, Faculty of Engineering, University of NottinghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/53182012-02-10T03:59:10Z2012-02-10T03:59:10ZThe Airbus A380 wing cracks: an engineer’s perspective<figure><img src="https://images.theconversation.com/files/7546/original/mtb9c2b7-1328842211.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">All 68 of the world's Airbus A380 have to be inspected.</span> <span class="attribution"><span class="source">Telstar Logistics</span></span></figcaption></figure><p>The <a href="http://www.easa.europa.eu/">European Aviation Safety Agency</a> (EASA) has ordered the inspection of all <a href="http://www.airbus.com/aircraftfamilies/passengeraircraft/a380family/">Airbus A380 superjumbos</a> following the detection of cracks in the wings of several aircraft.</p>
<p>Cracks were first discovered in December last year, in a Qantas-owned Airbus A380 that was being repaired after <a href="http://www.theaustralian.com.au/travel/news/airbus-says-new-cracks-found-in-a380-jet-wings-after-qantas-engine-incident/story-e6frg8ro-1226249107313">an engine explosion in Singapore</a>.</p>
<p>On January 20, the EASA <a href="http://www.casa.gov.au/wcmswr/_assets/main/lib91206/2012-0013.pdf">issued an Airworthiness Directive</a> (AD) grounding 20 A380 for visual inspections. </p>
<p>The 20 affected aircraft were early-delivery airframes (aircraft bodies without engines) – ten with Singapore Airlines, seven with Emirates, one with Air France and two Airbus test A380.</p>
<p>This initial directive allowed up to six weeks for a detailed visual inspection to be carried out on A380 that had completed between 1,300 and 1,799 flights. A380 that had completed more than 1,800 flights had to be inspected within four days.</p>
<p>According to <a href="http://www.reuters.com/article/2012/02/08/us-airbus-checks-idUSTRE8171DI20120208">EASA spokesperson Dominique Fouda</a>, the initial round of checks “found cracks in almost all of the planes inspected”.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/7540/original/fmx8qkhy-1328840398.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/7540/original/fmx8qkhy-1328840398.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/7540/original/fmx8qkhy-1328840398.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/7540/original/fmx8qkhy-1328840398.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/7540/original/fmx8qkhy-1328840398.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/7540/original/fmx8qkhy-1328840398.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/7540/original/fmx8qkhy-1328840398.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/7540/original/fmx8qkhy-1328840398.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption"></span>
<span class="attribution"><span class="source">Peter Pearson</span></span>
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</figure>
<p>As a result, the EASA <a href="http://ad.easa.europa.eu/ad/2012-0026">revised their AD</a>, requiring the inspection of <a href="http://www.nzherald.co.nz/world/news/article.cfm?c_id=2&objectid=10784512">all 68 Airbus A380</a> in operation worldwide, and the use of <a href="http://www.aviation-database.com/Technical_Aviation_Articles/Eddy-Current-Inspection-Equipment.html">high-frequency eddy current equipment</a> for crack detection. This is a commonly-used <a href="http://www.ndt.net/article/ecndt98/aero/031/031.htm">non-destructive evaluation technique</a> used to detect small surface cracks.</p>
<p>But just how much do we know about these cracks? And do the cracks have the potential to make the A380 unsafe to fly?</p>
<p>For a start, there are two different cracks being investigated:</p>
<ol>
<li>Hairline cracks around fastener holes in the internal wing structure, and </li>
<li>Cracks at the edges of the vertical web of the feet.</li>
</ol>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/7553/original/z8xf4b7z-1328846085.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/7553/original/z8xf4b7z-1328846085.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=543&fit=crop&dpr=1 600w, https://images.theconversation.com/files/7553/original/z8xf4b7z-1328846085.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=543&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/7553/original/z8xf4b7z-1328846085.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=543&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/7553/original/z8xf4b7z-1328846085.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=682&fit=crop&dpr=1 754w, https://images.theconversation.com/files/7553/original/z8xf4b7z-1328846085.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=682&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/7553/original/z8xf4b7z-1328846085.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=682&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Airbus</span></span>
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</figure>
<p>The fastener holes are located in “rib feet” which are L-shaped brackets extending from the [wing rib](http://en.wikipedia.org/wiki/Rib_/(aircraft/) for attaching to the aircraft skin, using bolts through these holes. It is my understanding that it is the rib-feet attached to the lower skin which have this problem.</p>
<p>A number of wing ribs are distributed along the wing – more than 40 on each wing of the Airbus A380 – and these run from the front to the back of the <a href="http://www.publications.parliament.uk/pa/cm200607/cmselect/cmtrdind/427/42708.htm">wing’s internal structure</a>.</p>
<p>These ribs help maintain the aerodynamic shape of the wing and transfer the aerodynamic and fuel loads to the spars – beam-like structures running along the length of the wing that are the main load-carrying structure of the wing. </p>
<p>The cracks found around these holes are being attributed to the manufacturing process used at Broughton, UK, <a href="http://www.airbus.com/company/aircraft-manufacture/how-is-an-aircraft-built/design-offices-and-engineering-centres/">where the wings are made</a>. </p>
<p>This manufacturing process may be related to the combination of the use of “<a href="http://engineeronadisk.com/notes_manufact/assemblya3.html">interference-fit</a>” fasteners and the loads being applied when the wing skin is attached to the wing.</p>
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<a href="https://images.theconversation.com/files/7539/original/vm7yskm8-1328840219.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/7539/original/vm7yskm8-1328840219.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/7539/original/vm7yskm8-1328840219.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=419&fit=crop&dpr=1 600w, https://images.theconversation.com/files/7539/original/vm7yskm8-1328840219.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=419&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/7539/original/vm7yskm8-1328840219.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=419&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/7539/original/vm7yskm8-1328840219.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=527&fit=crop&dpr=1 754w, https://images.theconversation.com/files/7539/original/vm7yskm8-1328840219.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=527&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/7539/original/vm7yskm8-1328840219.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=527&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Guillaume Horcajuelo/EPA</span></span>
</figcaption>
</figure>
<p>Interference-fit refers to the process whereby the fastener hole is made slightly smaller than the fastener diameter. When the fasteners are inserted, this has the effect of inducing stresses which offset the tensile stresses on the lower wing skin during flight, increasing fatigue life.</p>
<p>If the high loads being applied to the fasteners during assembly are not adequately accounted for, they will combine with the stresses arising from the interference fit, potentially leading to cracking. The particular type of <a href="http://www.keytometals.com/page.aspx?ID=CheckArticle&site=ktn&NM=227">aluminium alloy used</a> will also affect this joint behaviour where a balance has to be achieved between stiffness, strength and fracture toughness.</p>
<p>The cracks at the edges of the vertical section of the L-shaped rib feet have been reported as more severe than those observed around the fastener holes (Type II, using Airbus terminology, as opposed to Type I for the fastener hole cracks).</p>
<p>These cracks are likely to be at the corners of the rib feet where stresses are higher. These are of greater concern and could be fatigue driven. The AD also states that this condition, if not detected or corrected, could potentially affect the structural integrity of the aircraft.</p>
<p>That said, the cracks observed so far have not been on the main load-bearing structure of the wing. It would take multiple simultaneous structural failures along a number of ribs to give rise to a structural integrity issue. It’s worth noting that there are around 4,000 rib-feet on each A380.</p>
<p>So what can be done about these cracks?</p>
<p>Well, once detected, these faults may be repaired by various means, depending on the extent of damage. For small surface cracks, metallic or carbon-fibre composite patches can be used and there is always the more-costly alternative of part replacement. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/7537/original/nzh962rw-1328840046.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/7537/original/nzh962rw-1328840046.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/7537/original/nzh962rw-1328840046.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=389&fit=crop&dpr=1 600w, https://images.theconversation.com/files/7537/original/nzh962rw-1328840046.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=389&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/7537/original/nzh962rw-1328840046.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=389&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/7537/original/nzh962rw-1328840046.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=489&fit=crop&dpr=1 754w, https://images.theconversation.com/files/7537/original/nzh962rw-1328840046.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=489&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/7537/original/nzh962rw-1328840046.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=489&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="source">Dean Lewins/AAP</span></span>
</figcaption>
</figure>
<p>It’s worth noting that it’s not unusual for new aircraft to experience relatively minor structural (or other) problems once in service. These issues are bound to be minor, because the development of new aircraft entails a tremendous intellectual effort by thousands of engineers using advanced analytical techniques, sophisticated numerical simulation and extensive physical testing. </p>
<p>Airframers (such as Airbus) also work closely with national aviation certification authorities at all stages of development, to ensure the highest possible safety standards are met.</p>
<p>But for now, the EASA is <a href="http://www.reuters.com/article/2012/02/08/us-airbus-checks-idUSTRE8171DI20120208">sticking to its guns</a>:</p>
<p>“This condition, if not detected and corrected, may lead to a reduction of the structural integrity of the aeroplane.” </p>
<p>And Airbus representatives are <a href="http://www.theaustralian.com.au/business/aviation/crack-issue-widens-for-airbus-a380s/story-e6frg95x-1226267095647">sticking to theirs</a>:</p>
<p>“These brackets [in which the cracks have been detected] are located on wing ribs which are not a main load-bearing structure and, thus, the safe operation of the aircraft is not affected.”</p>
<p>It remains to be seen which analysis is closer to the truth, but it’s unlikely we’ve heard the last of the Airbus A380 saga.</p>
<p><strong>Further reading:</strong></p>
<ul>
<li><a href="http://www.ingenia.org.uk/ingenia/issues/issue31/bray.pdf">Supersize Wings – the challenges of designing the wings for the world’s largest passenger aircraft, the Airbus A380</a></li>
</ul><img src="https://counter.theconversation.com/content/5318/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brian Falzon does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The European Aviation Safety Agency (EASA) has ordered the inspection of all Airbus A380 superjumbos following the detection of cracks in the wings of several aircraft. Cracks were first discovered in…Brian Falzon, Professor of Aerospace Engineering, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.