Well, you and I both know then that airline companies design their planes to be as light as possible, and just barely pass whatever strength requirement there is for the part in question. Technically, there is nothing wrong with the airbus rudder failing when it's fully deflected left and right repeatedly. This is not it's certification standard, and the airbus rudder passes the certification standard.
This *seems* to be an issue where the FAA guideline is inadaquate. Airbus does have a case to say "we did nothing wrong", but on the other hand when you can fully deflect all other controls below manuvering speed and not have any other parts of the aircraft fall off, it seems to make the rudder limitation seem odd.
The rudder is hugely effective in combating turbulence that tries to roll the aircraft over. It's basically operating like an aileron to help roll the aircraft back with the ailerons. It shouldn't be the only control surface to use, but when you see how fast an airplane can be turned on it's back you want to use EVERY control surface to the MAXIMUM allowable limit to keep the aircraft from doing that. You're not going to pull out of an unusual attitude in an airliner like in a cessna, at least not close to the ground.
I will agree the aircraft manufacturers do, in general, try to make an aircraft as lightweight as is possible. I DO NOT agree, however, that all of them make aircraft that "just barely pass" whatever strength requirement there is for the part in question. Indeed, there is a long tradition of high quality manufacturing at such historic companies as Lockheed, Martin Marietta, McDonnell Douglas, Boeing, and many others throughout aviation history, as well as their contemporary entities of Lockheed-Martin, and The Boeing Company, who have built aircraft that EXCEED any such part strength requirement.
Aircraft manufacturers compete for product sales, and, unlike in some other industries such as textiles, have to prove their products are safer, faster, more capable, and more economical, in order to provide a valueable product that is desireable by a wide range of customers.
Historically, there are many cases when B-17 bombers, made by Boeing, would come back and land sucessfully even after heavy damage during WWII. During the Vietnam war there were many occassions where aircraft that bore heavy damage were likewise able to return to base and were of Grumman, Lockheed, and McDonnell Douglas origin. How many DC-3's are STILL flying today? Both military aircraft of the past and present, and civilian aircraft past and present, have been made stronger than called for. The fact is that American manufacturers do this because they know that 1) People's lives depend on the products that are produced, 2) they have to build them better and stronger to compete, 3) they don't want poor products to result in litigation that would put their industry, and themselves at risk.
The problem here is that we have no such singular corporate entities with single government control overseeing Airbus manufacturing and design, and with the political subsidies involved in the EU, and the types of failures that are occurring, that the quality control, manufacturing, and design of the Airbus aircraft involved should be very closely examined.
Boeing, for instance, regularly manufactures both commercial and military aircraft beyond what the minimum requirements are. In fact, even Cessna aircraft red-lines all their aircraft while still "in the green" at the plants to make sure they are able to withstand all the forces and limits published, and then some. Most of the time manufacturers here will publish lower limits by a fairly good percentage margin (a margin which I will not mention here so as not to induce false sense of bravado in the less experienced pilots that may read this). Suffice it to say that your assumption that all aircraft are built to satisfy minimums and not much else is just flat out wrong. I don't even believe Airbus would do that.... but there does appear to be a problem in this one class of aircraft with a common area of that aircraft, and it needs to be looked at for the safety of the flying public.... in my opinion.
Big discussion here http://www.pprune.org/forums/showthread.php?s=&threadid=166083
Date: 4/17/2005 9:49:16 PM
I am always amazed by these US against Airbus discussions. I believe it was the B737 that had some serious rudder problems
in the past in exactly the same circumstances.
To say that Airbus is cutting more corners and builds their airplanes to barely scrape by the regulations is unrealistic.
You want an example of an aircraft returning safely home with battle damage....how about that Airbus last year in the middle east
who was attacked with RPGs or similar weapons and had major portions of the flight controls shot off...she made a safe landing.
Quite possibly because it was an Airbus come to think of it.
Aside from the fact that even the nasty Europeans don't lightheartedly risk killing hundreds of people is that fact that in this
day and age two other things are very important. Reputation and unfortunately lawsuits especially here.
Please don't misconstrue what I said earlier as an inference that I think Airbus aircraft are sloppily designed or that they don't care about safety. I think very highly of them indeed (though Boeing does make better, and safer products ). Some of the rudder problems you were talking about with the B737 related to maintenance issues more than design flaws, but Boeing did correct the design to make the maintenance issues more "idiot proof".
I still think there is a high potential for unpredicted flutter causing the rudder issues in the Airbus's in question. It likely didn't show up in earlier production runs of the same model because in the older runs, they used an aluminum rudder. They switched to composites for the rudder starting with, I believe, the 1998 or 1999 production years.
Just wanted to set the record straight. No aircraft manufacturer wants to ignore any safety issue. It's just not worth the bad-will, not to mention potential litigation if something happens.
FYI, the C-17, F/A-18 C through E variants, F-15, A-10, B-747, B-727, MD-80, and other aircraft have all had their share of use with the military, and some of them have come under attack. Each of them has also made safe landings even after sometimes major structural damage. In one instance, an F-15 landed safely after it's right wing had been taken off right down at the wing root by an air-to-air missile. The F-15's design gets 70% of it's lift from it's fueselage and empennage, so it was actually able to be landed sucessfully. A-10's during the first Iraq war got pretty well shot up, and even came back and landed with blown tires and structures that looked like swiss-cheese in some areas.
maybe I was jumping the proverbial gun a little there...it just is an ever revolving issue and often fueled more by patriotism than actual hard facts...not acusing you of that mind you.
If I remember right the F15 was an israeli airforce airplane and the pilot kept his head in a situation that was in no training text book.
The 737 rudder issue was initally blamed by Boeing on pilot error in the first two accidents if I remember correctly and only after another incident where the plane was recovered by the crew and the real problem was discovered did the company fix the problems...all this is based on what an outsider can put together via WWW and media.
You may very well be right in your description of the cause for the Airbus rudder issue. I don't have any knowledge of which changes they have made to their design. Sometimes a new design while better in many respects can cause an unforseen negative effect.
Of course as a 100% german national I am a little more partial to the Airbus product...
Date: 4/18/2005 11:16:20 PM
Oh - and speaking of cabin amenities. There was a TWA 727 that I'm sure I flew in more than once (although I never checked N-numbers) towards the end of the company's independence. It wasn't the one painted with the Ram's helmet (I flew on that one twice), or even one in the ''One World'livery, but one that had the loudest cabin relief valve I've ever heard. It was so loud that I mentioned it to the crew on landing, thinking it was a slightly leaky seal at the over-wing emergency exit (acoustically, you really couldn't tell where it was coming from, except near mid-cabin). They said they knew about it and that the valve was just noisy. The plane seemed to live on the St. Louis - Omaha route. Unless that's something common to older 72's, I'm sure I got to ride that plane at least three times.
Last war story regarding airworthiness - and Ted, you can verify this with one of the IA's at your favorite FBO since it is his story. When TWA bought part of the defunct Eastern's DC-9 fleet, the cabins, naturally, were stripped, inspected, and repaired as necessary. At the rear lav, an area where corrision is a problem, under the carpet, our friend found a repair made to the cabin floor by an EAL mechanic. Apparently, the EAL employee was very conscientious about his company's money, the environment, or both. The repair was made with recycled aluminum - a 7-Up can slit up the side and riveted in place.
Like control of nuclear weapons, it's all based on trust...
Well...I've never heard of that incident with the soda can! Very interesting! I've never had that cabin repress valve noise be a problem on the 727's I've flown on in the past, but it is a noisier aircraft than the newer ones to be sure. Since I'm in the military side, and not the commercial side, I'm not as privy to all the details to know if that was a general problem or not that you encountered. I suspect it was isolated, but I've no proof one way or the other on that.
Yes... trust in one's manufacturer is both hard earned, and highly fragile. That's why there is so much attention to detail and safety among all manufacturers of aircraft and their suppliers. It's rare to find true negligence or purposeful concealment of issues. It has happened in the past among various companies, but the business environment today just doesn't lend itself to that sort of thing. Not and keep that public trust or business.