backtop


Print 32 comment(s) - last by letmepicyou.. on Jan 27 at 2:25 PM


  (Source: United Artists)
Latest issues come at an inopportune time for Airbus who is trying to fight off Boeing's superjet entrant

The Australian Licensed Aircraft Engineers Association (ALAEA) is sounding the alarm on one of the world's most iconic passenger aircraft designs, claiming that they are suffering from a design flaw.

The aircraft in question is the Airbus A380, the world's largest passenger jet.  The four-engine aircraft is manufactured by Airbus, a subsidiary of The European Aeronautic Defence and Space Company N.V. (EADS) (EPA:EAD).  

The airplane, which saw its maiden flight in April 2005, and saw an Oct. 2007 commercial introduction, has enjoyed having no real peer over the last several years, as it offers almost 50 percent more floor space than The Boeing Comp.'s (BA) 747-400.  It packs 478 square metres (5,145.1 sq ft) of floor space.  The A380-800 variant has a range of 15,400 kilometres (8,300 nmi; 9,600 mi) and has a cruising speed of Mach 0.85 (about 900 km/h or 560 mph at cruising altitude), meaning that it can travel from Hong Kong to New York City, without refueling, in only 17 hours.

But according to the Australian engineering group, the deployed aircraft show cracking in their wing ribs.  Steve Purvinas, secretary of the ALAEA, comments, "We can't continue to gamble with people's lives and allow those aircraft to fly around and hope that they make it until their four-yearly inspection."

The cracks were first found on A380s deployed in the fleets of Singapore Airlines (SGX: C6L) and Qantas Airways (ASX: QAN) (which primarily operates out of Australia).  The two airlines account 26 out of the 50 delivered passenger A380-800s, as the second and third largest A380 users.

A380 Plane
The Airbus A380-800 [Image Source: Qantas Airways]

So far no American airline company has adopted A380.  FedEx Corp. (FDX) and United Parcel Service, Inc. (UPS) placed commercial orders, but later cancelled after being inconvenienced by delays from the aircraft-maker.

BBC News quotes Airbus representatives as confirming the wing rib cracking, but insist it's harmless, and that passengers shouldn't be worried about the cracking wings.  States the company, "We confirm that minor cracks were found on some noncritical wing rib-skin attachments on a limited number of A380 aircraft. We have traced the origin. Airbus has developed an inspection and repair procedure, which will be done during regular, routine scheduled four-year maintenance checks. In the meantime, Airbus emphasizes that the safe operation of the A380 fleet is not affected."

Qantas has thus far repaired two of the members of its fleet that it spotted cracks in.

The A380 had been being considered as a possible upgrade option for the President of the United States' plane, Air Force One.  This is not the first issue to afflict the craft -- earlier wiring issues delayed shipments of the aircraft.

The cracking issues are bad timing for Airbus.  The company is currently trying to sell new customers on the aircraft and ward off Boeing, who just unveiled the Boeing 747-8 Intercontinental, a craft that finally brings Boeing abreast of Airbus in the mega-aircraft department.  The 747-8 took its maiden flight in Feb. 2010.

Source: BBC News



Comments     Threshold


This article is over a month old, voting and posting comments is disabled

That's just great !
By JoJoman88 on 1/9/12, Rating: 0
RE: That's just great !
By ksherman on 1/9/2012 12:39:01 PM , Rating: 5
"These aren't the cracked wings your looking for"


RE: That's just great !
By Solandri on 1/9/2012 1:20:16 PM , Rating: 5
1) Cracking in aluminum structures is inevitable. Aluminum does not have a fatigue limit - there is no way to build with it in a manner which does not produce cracks that grow with use.
http://en.wikipedia.org/wiki/Fatigue_limit

This is why airframes are retired after a bit over 100,000 flights. You build them knowing that cracks will develop, and rely on design to mitigate the effects, and inspections to catch any cracks which grow faster than expected by the design. After a certain number of uses, you throw the whole thing away. The mere presence of cracks is not indicative of a problem.

2) This is not a primary load-bearing member. The purpose of the rib is give the skin of the wing its shape. A failure here would simply result in the skin of the wing flexing a little bit more. Any load being carried by the cracked section would be transferred over to other parts of the rib, or to adjacent ribs. The main load-bearing member of the wing is the spar, which runs lengthwise and connects the wing to the fuselage.


RE: That's just great !
By mcnabney on 1/9/2012 1:23:47 PM , Rating: 3
Yes, but isn't this a little early in their service life?


RE: That's just great !
By FITCamaro on 1/9/2012 1:28:27 PM , Rating: 2
Good post.


RE: That's just great !
By Keeir on 1/9/2012 2:01:20 PM , Rating: 6
A few points

1. Airframes currently do not have a mandated retirement limit. There are manufacturer's suggested lifespans. The FAA is working on a mandated retirement limit. The limit will be different for different airframes. For something as large as an A380, the limit would likely be 30,000-40,000 flight cycles. (Due to the large oval nature of the airframe, the stress caused by internal pressure will be high.)

2. The existence of cracking does not show a problem. The size of cracking in this case is suggesting a potential problem. Likely there is an installation issue, which is resulting in high local fatigue stresses/stress corrosion.

3. Errrr.... While something may not be a load bearing area, that doesn't mean it is not important. The aerodynamic surface of the wing is -very- important is several areas. For example, the leading edge. A panel failure of the leading edge can make certain maneuvers difficult/impossible. If the pilot is unaware of potential issues, he would be faced with a difficult situation where his instruments and computer are telling him there is a problem, but he has no real knowledge of his new limitations.

Potentially, if the A380 computer system is sensitive enough to detect changes in airflow over the wing and inform the pilot of their changed flight envelope, I can agree that this issue is relatively minor. But Civil Aviation Agencies typically don't talk out like this unless there is a relatively high danger.


RE: That's just great !
By bug77 on 1/9/2012 2:38:53 PM , Rating: 2
quote:
This is not a primary load-bearing member.


Then why did it crack first? Something doesn't feel right.


RE: That's just great !
By Keeir on 1/9/2012 3:58:35 PM , Rating: 5
quote:
Then why did it crack first? Something doesn't feel right.


When building something like an airplane that is very weight critical, there is often very little tolerance for mistakes in installation. For example, an unshimmed gap of just 0.050" between two parts can lead to cracking during installation or a very short time after installation. This would not be unheard of in an area like a wing where there are several complex curves over a large area.

This is a very different situation that most people are used to in real-life. Most things used on a daily basis (furniture, cars, houses, etc) have very high initial margins of safety to allow for poor maintenance, etc. This also allows for poor installation techniques.

The A380 likely has some aluminum panels that are 0.050" or less. (I do not have any knowledge on the A380, but Aircraft typically have aluminum panels ranging from 0.016" to .5" with even large models having some areas at <0.050") Consider how much force it would take to bend a 2" x 4" enough to displace the end 2" when your holding it 4", 6", 12", etc away. Consider how durable you would consider the resulting structure. That's what as little as an 0.050" (3/64") gap can do to an aircraft.

From the description, its very likely that
A.) A mechanic is installing the part outside standard installation procedures due to fabrication process difficulties (for example the part is warping during heat treatment)
B.) An engineer made an error is measuring tolerances and an unplanned for gap is occurring
C.) A plan writer is leaving off an important step. For example, deburring or fillet relief cutting holes such that fastener installation or hole cutting is leaving defects that turn into cracks.

None of these is particular unusual or something alarming.

It is unusual to have a private group of civil aviation engineers make a public statement about an issue. Clearly there is a mild/major disagreement how fast the problem should be fixed...


RE: That's just great !
By fteoath64 on 1/14/2012 2:40:44 AM , Rating: 2
" Clearly there is a mild/major disagreement how fast the problem should be fixed".

The article suggested that a 4-year inspection cycle meaning another 2 years for a plane that is 2 years old. This is certainly UNACCEPTABLE even though it might be stated in the contract becuase "load bearing" and "non-load bearing" can both severely affect steering accuracy,hence risking the lives of the passengers and crew.
One would suggest Airbus replace one such panel and test for its tensile strength and metal fatigue degradation in order to determine if immediate replacements is needed. It is only fair, don't you think ?.


RE: That's just great !
By FaaR on 1/9/12, Rating: 0
RE: That's just great !
By Strunf on 1/9/2012 12:40:50 PM , Rating: 3
Completely agree with you, it's the average Joe that should say if a plane is safe or not to fly, engineers are just like any other average Joe with the exception that they are payed for their uninformed opinion!


RE: That's just great !
By kleinma on 1/9/2012 12:45:25 PM , Rating: 2
Doesn't sound like anything some chewed bubble gum and duct tape can't fix.


RE: That's just great !
By Keeir on 1/9/2012 4:14:36 PM , Rating: 3
This seems like a good place to put a reminder.

Modern Aircraft Travel (Plane designed and made after 1975) is the safest per mile mode of transportation.

For example, if you were to live on a B767, one of the highest rate modern aircraft due to the number of high-jacking incidents, you would only experience one fatal flight incident every 1,334 years. If you spent all day in a moving car, the incident rate would be more like one fatal incident every 400 year. All while covering 8 times the distance or more in the plane. Air Travel on a per mile basis is an order of magnitude safer than most people's preferred mode of travel.

(B767 has 1 full lose event per 2.85 million flights. Each flight on a B767 is ~4 hours long on average. 2.85 million * 4 hours * 1 day/24 hours * 1 year/356 days --> 1 full life lost event per 1,334 years. Last year 30,000 people died in car accidents over around 105,000 million passenger hours or 1 death per 3.5 million passenger hours * 1day/24 hours * 1 year/356 days)


RE: That's just great !
By fic2 on 1/9/2012 5:53:18 PM , Rating: 2
quote:
For example, if you were to live on a B767, one of the highest rate modern aircraft due to the number of high-jacking incidents, you would only experience one fatal flight incident every 1,334 years.


Yes, but if your fatal flight incident happened in year one I bet you would be pretty bummed.


RE: That's just great !
By Keeir on 1/9/2012 6:12:27 PM , Rating: 2
Some people choke to death while drinking (even just water). Just because there is a statistical chance that while doing a certain activity death is possible is no reason to stop doing it.

Air Travel is safer than pretty much all other forms of -travel-. If you find yourself in a position where you need to travel several hundred miles, then its about as safe as it can be done, and significantly safer than driving a personal car (which on a per mile basis is between 25-50 times more dangerous for death).


RE: That's just great !
By JoJoman88 on 1/9/12, Rating: 0
RE: That's just great !
By JNo on 1/9/2012 8:09:33 PM , Rating: 1
Firstly, there are 365 days in a year, not 356 (and 365.25 if you account for leap years). That brings you to 1 full lose event every 1,301 years. I don't know what a "full lose event" is and neither does google (http://www.lmgtfy.com/?q=%22full+lose+event%22) and you don't define it.

Assuming you mean an aircraft crash, let's just be conservative and say everyone dies (often the case) - you then need to account for the typical number of passengers on a 767 - let's call it 300 passengers if not at full capacity. So that's 300 lives lost every 1,301 years or and average of 1 life lost per 4 and third years.... making the car 100x safer per hour.

On a "per mile" basis we need to know the average speed of all cars and all B767s which I don't. Guessing 40mph for car and using 500mph for the B767. Call it a factor of 12 difference and the car is still (100 div by 12 =) 8x safer per mile.

And there's more - a car is often door to door travel whereas with aircraft you'll usually need to take trains and cars to get to / from airports - altering the safety rate of the *overall journey*. Plus with air travel you need to account for 2hrs check in time as well as travel to/from, reducing the average speed of the journey, if not the distance travelled or death per mile figures (I'm sure there are some average death per hour spent waiting at the airport figures out there somewhere!)

Obviously if the "full lose event" really is a single death then the planes win and yes, travel on a per mile basis swings further to their favour. Maybe you can point out a public source of your numbers too? (the 1 per 2.85m flights)?


RE: That's just great !
By Keeir on 1/9/2012 10:11:26 PM , Rating: 4
Sorry friend. You need to think things clearly through.

Lets for example say that a B767 typically flys with 250 passengers.

Over 2.85 million flights, the fatality rate is 250 passenger deaths to 712 million safe passenger trips. Or 1 death per 2.85 million safe trips. Number of people involved in a crash is fairly meaningless, unless for some reason a nearly full flight is more likely to crash than an empty flight.

Source: http://www.airsafe.com/events/models/rate_mod.htm

Each trip on a 767 is roughly 4 hours long. Making it 1 death per 11.4 million hours. Flight length is typically around 1,600 miles so, 1 death per 4.65 billion miles.

Now for cars, NHSTA shows that in 2009, one of the safest years every recorded, 1.14 deaths per 100 million miles, or 1 death per 87.7 million miles. The average over 1995-2009, far less than the 767 aircraft, is 1 death per 75 million miles. Assuming ~35 MPH average speed, in 2009 the death rate was roughly 1 death per 2.5 million hours. Average over the 767 in Service Life of 1985-2010 for cars is more like 1 death per 50 million miles.

Source: http://www.nhtsa.gov/FARS

The way I count things, that makes the 767 roughly 50 times safer per mile (Average over 1985-2010 versus safest year on record for cars). Which BTW means I also ignoring the huge number of non-fatal but significant injury events that occur on cars.

In other words, if I am flying Seattle Washington to Washington DC, my chances of death on that flight of the B767 is roughly 1 out of 2 million.

If I choose to drive from Seattle Washing to Washington DC, my chances of death are 1 out of 32,000.

If I had to drive more than 40 miles to the Seattle Airport and away from the Washington DC airport, the car section of the trip was MORE dangerous than the air portion.

I realize many people have an illogical fear of flying due to the loss of control and the high publicity given to a single accident.

But this story is correct

http://travel.usatoday.com/flights/2011-01-21-RWai...

From 2007-2010, there were THREE years where the US major airlines had zero deaths. Zero. Total death toll was 50 overall. Yes 50. In comparison Car travel netted 155,000 + deaths and several million injuries.

Sorry, people have to be brainsick to believe that flying in the US, Europe, Japan, Australia, etc is less safe than driving in any of those countries. Now if you choose to fly the friendly skies of Somolia, then that is a different story.


RE: That's just great !
By JNo on 1/10/2012 4:08:58 AM , Rating: 2
Yeah you're right - rethinking about it the fatalities per crash is not relevant. BTW I don't have an irrational fear of flying - I love it - I just wanted to understand the figures better.

Anyway, I guess you still contest that there are 356 days a year since you didn't bother to publicly correct that... and I don't know where Somolia is :)


RE: That's just great !
By Keeir on 1/10/2012 11:29:59 AM , Rating: 2
Friend, those are small typographical errors. The intent is fair clear. When I used 356 instead if 365, I used to consistantly...


RE: That's just great !
By ballist1x on 1/10/2012 5:06:07 AM , Rating: 2
Yea but you can get out of the car, you can dodge other cars - to an extent. You have some form of control.

if something ever goes wrong at 30,000 feet, well you're more than a little bit stuck really arent you?

Sure the percentages are better- but the absolute outcome would be far worse in a plane than a car.


RE: That's just great !
By Gondor on 1/10/2012 8:14:39 AM , Rating: 2
Well, you can dodge the ground om that case, yeah ?


RE: That's just great !
By Keeir on 1/10/2012 11:41:26 AM , Rating: 2
quote:
but the absolute outcome would be far worse in a plane than a car.


Errr... I am probably a bit confused.

Pretty sure death is death. I guess the few minutes of potential terror in an aircraft is worse... but really, your going to trade almost a 50 times greater chance of death, just so you can slowly bleed out in a car versus wait for impact?


A380 for AF1?
By MonkeyPaw on 1/9/2012 2:55:15 PM , Rating: 2
How can the USA even consider an import for AF1? Have we outsourced all our plane building, too?




RE: A380 for AF1?
By nafhan on 1/9/2012 3:05:09 PM , Rating: 2
Obviously: the 747 is not big enough.


RE: A380 for AF1?
By Ringold on 1/10/2012 12:09:43 AM , Rating: 3
quote:
The A380 had been being considered as a possible upgrade option for the President of the United States' plane, Air Force One.


I agree with some of the disbelief. When other world leaders fly commercially, is AF1, a golden chariot by comparison, not enough? -.- Plus, if there's anything that should be bought domestically purely as a symbol, wouldn't it be that?


RE: A380 for AF1?
By michael67 on 1/10/2012 6:13:18 AM , Rating: 1
Ofc Boeing is gone get the contract, but that dose not mean the A380 is not gone be used as a bargaining card.

And unless Boeing comes whit a ridicules high offer, and forces the government in a do or die situation, and overplays the domestic card, Boeing is getting the contract.

And if they don't get it, they just sue and cry wolf again and get it that way, just like with the tankers.


RE: A380 for AF1?
By Keeir on 1/10/2012 11:37:10 AM , Rating: 2
quote:
When other world leaders fly commercially


#1. When its a documented fact that US airliners can be hi-jacked, I am not sure having the president fly commerical all the time is a great idea

#2. List of Countries that maintain private large aircraft for high government use

Australia
Belgium
Bulgaria
Brazil
Canada
Denmark
France
Germany
... List goes on.

Maybe you should ment to say,
"When other world leaders fly commerically to make a political statement, why does US leaders feels that just AF1 is not enough of a golden chariot?"

Because I assure you that most if not all First, Second, and Third world countries maintain a private fleet of aircraft for use by high officals, and the high officals usually use them.


RE: A380 for AF1?
By Natch on 1/10/2012 9:03:47 AM , Rating: 2
We could always convert a C-5 Galaxy. That's big enough to haul an M-1 tank, and I'm sure they could split it into two decks, for more room. That, or have enough room for a basketball court, so Mr Obama could enjoy some sport while flying here and there. ;)


Relax
By Beenthere on 1/9/2012 1:28:50 PM , Rating: 1
This ain't no big deal or unexpected. It's very much part of airframe design. It's not like the planes are falling out of the sky. If mods need to be made, they'll be made.




Excuse me for asking but...
By letmepicyou on 1/9/12, Rating: -1
RE: Excuse me for asking but...
By letmepicyou on 1/27/2012 2:25:12 PM , Rating: 1
Now generally I don't take an exception to negative ratings, but what, exactly, is there to down on about drawing parallels between how honest one corporation is and how honest another most likely will be???

If you understand anything about economics at all, you realize that any time the truth may harm the company or endanger the status quo, they'll sweep it right under the rug and do whatever they have to do to make it go away.

It almost seems like some folks out there reading these posts don't want anyone to see or think about anything "Fukushima" related...


"And boy have we patented it!" -- Steve Jobs, Macworld 2007














botimage
Copyright 2014 DailyTech LLC. - RSS Feed | Advertise | About Us | Ethics | FAQ | Terms, Conditions & Privacy Information | Kristopher Kubicki