Af 447

[KMEM]

Aviation insiders are suggesting that one should not fly on an Airbus, especially the 330. There is evidence that the tail disentigrated in an encouter with violent weather. These same insiders are suggesting that the "pitot tube" issue is a red herring. They are suggesting that the "tail feathers" are not up to airline standards.

 

I am not suggesting that we should abandon any such travel but I am suggesting that perhaps we should have a regard for any weather that might be encountered on a flight on an Airbus. That, however, is my standard advice.

 

Best regards,

KMEM

[AdamSmith]

I am not suggesting that we should abandon any such travel but I am suggesting that perhaps we should have a regard for any weather that might be encountered on a flight on an Airbus.

Sage. But is there much way for passengers to know what the weather will be at 35,000 feet, halfway between two continents, until they are actually up there?

 

I realize the Airbus tail issues have to do with rudder movement. But what worries me is our relatively immature engineering understanding of the composite materials those tails are made of -- their fabrication, assembly and fastening, maintenance, and diagnosis for pending failure.

 

What worries me more is that Boeing's new 787 will have an all-composite fuselage. I know a lot of Boeing engineers, and have great respect for them. But for the first couple of years in production, that airframe will be a flying test lab to see if they got the composites science right. Count me out, if it were possible.

[KMEM]

No, if you are doing very long distance flying, you will be at the mercy of chance. And, especially if you are crossing the equator, you will almost surely run into SOME nasty weather. Flights that are mostly east west or vice versa give one a little more opportunity to see the short and long range forecast. I also realize if one bought a discounted ticket that changing ones flights at the last minute will be expensive. If I had a "real" crystal ball I would be rich, if not famous or famous, if not rich. We can only do the best we can with the information we have at hand but just blindly trusting to luck is not exactly what I have in mind for me.

 

Boeing as well as other manufacturers have learned a lot in a relatively short period of time (sometimes by necessity). I think Boeing's learning curve was straight up after the Aloha "convertible" accident. As you will recall, that involved composites in their earlier days.

 

However, you are correct. Composites have not fully matured. And, any airliner will have "teething" problems. It seems that any electro-mechanical device has these to include cars, computers and well as airliners, etc. Very few prefer to think of themselves as "test" drivers, test passengers, etc. But, in fact, we often are.

 

I am not predicting doom and gloom. I am only reporting some things that are currently circulating in the industry.

 

Best regards,

KMEM

[+ Charlie]

I happened to be on a flight over the Atlantic at exactly the same moment that AF447 went down, but like the passengers on that flight, I had no way of predicting what the weather would be, or whether the 767 I was on would handle it any better than the Airbus. In fact, I wonder whether the pilots really knew what they would encounter, since they told us they expected a smooth flight, yet midway we hit sudden turbulence; the same thing happened yesterday as we approached Newfoundland. I feel the same way about flying that I do about driving on the Interstate: what will happen, will happen (drunk driver, blowout, oil spill, jack-knifed truck, etc.); the only difference is that on the Interstate I may have at least some control about my response to it.

[Luv2play]

KMEM, Since you appear to have some knowledge of the issues I have a question to pose to you. You will no doubt recall the commercial jet that crashed off the coast of New York several years ago after the tail rudder fell off because of air turbulence caused by following another aircraft too closely. I don't recall what kind of airplane it was. That plane was at a much lower altitude than AF447 but I seem to remember that the pilot was able to issue a mayday alert. This didn't happen in the AF case. If something happened to the tail, wouldn't the AF pilot have been able to radio a mayday?

 

Also I understand from press reports today that examination of bodies recovered is suggesting the plane blew up or came apart violently to cause multiple fractures to the passengers. This again would not be consistent with a tail failure.

 

There was also a Japanese airplane that crashed a few decades ago that lost its tail at cruising altitude and continued to fly for almost an hour because of the skill of the pilot. Unfortunately he wasn't able to steer the plane to a safe place but the plane kept aloft for a long time. The passengers knew they were on a doomed flight since many wrote last messages to their families which were later recovered. I also believe one infant survived that crash which was a miracle in itself.

 

Anyway, as you can see, I follow these cases somewhat closely but that said, there are few planes I wouldn't get on. I've even enjoyed flights on planes as old as I am since these planes are virtually entirely rebuilt over and over as long as they are kept airworthy.

 

On a side note, given today's incident where a 61 year old pilot on Continental Airlines died of natural causes while on an intercontinental flight, what do you think of the rule change approved by Congress last year that changed the retirement age for pilots from 60 to 65? Congress was apparently persuaded that this kind of thing wouldn't happen! It didn't take too long to show how erroneous that advice was.

[AdamSmith]

the tail rudder fell off because of air turbulence caused by following another aircraft too closely. I don't recall what kind of airplane it was. That plane was at a much lower altitude than AF447 but I seem to remember that the pilot was able to issue a mayday alert. This didn't happen in the AF case. If something happened to the tail, wouldn't the AF pilot have been able to radio a mayday?

 

Also I understand from press reports today that examination of bodies recovered is suggesting the plane blew up or came apart violently to cause multiple fractures to the passengers. This again would not be consistent with a tail failure.

 

Seems a number of tail-failure scenarios plague Airbus craft. In the recent case over the Atlantic, seems likely from available evidence pre-black box recovery that system (speed-sensing, tail-rudder-autodirection, etc.) failures could have doomed plane before pilots, trying to save plane (esp on Airbus contrarian-minded-computer-controlled, unlike Boeing), could have had time to fool with mayday transmissions.

[MsGuy]

"system failures could have doomed plane before pilots, trying to save plane (esp on Airbus contrarian-minded-computer-controlled, unlike Boeing), could have had time to fool with mayday transmissions."

 

Your post is a bit cryptic. Does this mean that Airbus auto-systems are significantly more difficult for pilots to over-ride as compared to Boeing? Or that Airbus systems are more likely to take irreversible actions before pilots can intervene? Or what? Sorry, but I'm not too sophisticated about these things.

 

Either way, I'd rather be killed by good old pilot error than by some programmer who failed to allow for an unusual combination of circumstances. At least I'd have the comfort of knowing the SOB responsible was going down with me.

[KMEM]

L2P-

 

In order of your questions:

 

1. AA 587 had the vertical stabilizer fail because of "over exuberant" use of the rudder. We pilots have been taught forever that if the aircraft is below a certain speed, then full deflection of any control surface would not harm the aircraft or the control surface. That proved to be incorrect. It seems that if the pilot flying moves the rudder to full deflection in both directions alternatively, it might fail the rudder or the rudder attachment called the vertical stabilizer. That is exactly what happened on this flight involving an Airbus 300 following a larger aircraft. When this aircraft encountered the wake turbulence of the leading aircraft, the pilot flying reacted too forcefully to the situation. He didn't know what the ultimate result might be and no one else did until this accident. Training on airliners as well as all other aircraft has been changed as a result of this accident. That still begs the question of how "weak" was the rudder on this Airbus.

 

2. The JAL aircraft was a 747 that had been repaired by Boeing. The repair was to the aft pressure bulkhead and this self same bulkhead failed in flight because the repair was improper. This failure basically failed the function of the tail so there was no pitch (up and down) control or rudder (left and right) control. The result was the aircraft wandered around with little control for some hours before crashing. This provided time for some to call and write to their families. No doubt it also caused others to suffer longer than anyone might hope.

 

3. There is a long story to go along with increasing the retirement age on airline pilots to age 65. Briefly, other countries did this a long time ago. Health care and prediction has improved enormously since the age 60 rule was first instituted. The unions preferred age 60 and out so their younger membership would grow and go. Pilots approaching 60 almost unanimously wanted to keep flying unless they had a health problem which most did not. After many years of petitioning the Congress, infighting with the unions, etc. the law was changed. Perhaps you can answer what the bottom line is by answering this question. Ever hear of a 40 year old falling over dead from a heart attack? No predictors are perfect. Your time is your time. That is one reason they have at least 2 pilots on every flight.

 

I am so glad that you have enjoyed flying all these years and hope you continue to do so for many years to come. I also appreciate that you realize that aircraft are maintained to continuous airworthy standards but no rules or standards are ever perfect.

 

PS- AF 447 did issue a mayday of sorts in that the ACARS sent messages about the systems failing. The Aircraft Communications Addressing and Reporting System is a SATCOM (satellite communications) method for the aircraft and usually maintenance to keep in contact. It is possible for the crew to use this system to communicate in a manner similar to email. Otherwise, in that part of the world they will be relying upon HF radio communications. HF has a lot of issues that I will not go into here. Suffice it to say if a crew has a handful of problems they will not likely turn to HF for any thing and will not have or take the time to do email type communications.

 

Charlie-

 

Turbulence is often caused simply by the velocity of the blowing wind. The winds are ordinarily very strong over the Atlantic. Therefore it is fairly common to encounter some turbulence somewhere over the Atlantic. If pilots issued warnings every time the wind blows there would never be any meal service, such as it is. On the other hand, it is very good advice to stay in your seat as much as possible with your seat belt at least loosely fastened. Bascially, the pilots do the best they can with the information available to them to include their personal experience.

 

AS-

 

As you mention, the Airbus has had more than one problem with the tail feathers. Personally I prefer to have manual back up and reversion. Computers do fail, no matter how many are on board.

 

 

Let us not forget the UA flight that lost all hydraulics (almost as bad as computers) when the tail engine shed a fan disk and cut through all the lines. The heroic efforts and experience of the crew on board in landing (more of a semi-controlled crash than a landing) at SUX (Sioux City) saved the lives of more than half of those on board. It is never pleasant to realize the loss of life of even one but the other choice was the lives of all.

 

Best regards,

KMEM

[Guest zipperzone]

 

Also I understand from press reports today that examination of bodies recovered is suggesting the plane blew up or came apart violently to cause multiple fractures to the passengers. This again would not be consistent with a tail failure.

 

 

L2P: Wouldn't crashing into the ocean qualify as "coming apart violently"? I would have thought an autopsy to determine if there was water in the lungs would be an indicator of whether they died by drowning or before they hit the water. But perhaps floating around for days in the ocean would cause water to be in the lungs in any case.

[KMEM]

Zip-

 

From what I have read, not know, bodies do not get water in their lungs, only living people do. I believe they are supposing that when whole bodies are found in the water the breakup of the airframe was in the air because crashing into something as hard as water at several hundred mph does more personal damage as you mentioned, fractures and the like.

 

It does seem more likely the tail failed (likely because of the storm) and the readings sent via satellite were simply reports of the aircraft losing its' systems. The pitot business seems more and more like a red herring.

 

Best regards,

KMEM

[Luv2play]

Zip, if you recall the SwissAir flight that crashed in Nova Scotia, that plane hit the water at full speed and there was very little left that was larger than a suitcase. No whole bodies were recovered, only body parts and some were never identified or recovered. The AF flight is different. As I understand, all bodies that have been recovered are identifiable and only show signs of broken arms, legs and other fractures.

 

This is consistent with the Lockerbie disaster, where the PanAm plane was blown out of the sky. There, many bodies were recovered in one piece as they had been ejected from the plane before it crashed. Also bodies were scattered over a distance of miles. That is similar to the AF crash.

 

I saw a picture of a wall unit on the AF plane that looked like a galley installation. It was in one piece and measured 8 or so feet long and 6 or so feet high. It was in one piece floating in the water. There is no way this was involved in a crash into the water at full speed, it would have been shattered. But it could have fallen out of the sky in one piece.

 

Time will tell what happened but I am not ruling out a bomb.

[AdamSmith]

Does this mean that Airbus auto-systems are significantly more difficult for pilots to over-ride as compared to Boeing? Or that Airbus systems are more likely to take irreversible actions before pilots can intervene?

 

"...Should pilots or a computer have the ultimate control authority over a commercial jetliner as the plane approaches its design limits in an emergency?

 

"Airline passengers can't see it, but this is the most significant difference between Boeing and Airbus planes.

 

"Dramatic advancements in technology have made it possible for planes built by either manufacturer to be flown by computers from shortly after takeoff through the landing.

 

"But Airbus has taken a much different philosophical approach to using computers than its rival. The European airplane maker designed its new fly-by-wire jets such as the A320 with built-in hard limits, or "protections."

 

"The Boeing Co., on the other hand, believes pilots should have the ultimate say. On Boeing jets, the pilot can override onboard computers and their built-in soft limits..."

 

http://www.seattlepi.com/business/boe202.shtml

[+ ArVaGuy]

In regard to new technologies and composite materials I'm reminded of the early days of jet aviation and the series of deadly crashes involving the BOAC DeHavilland Comet. This particular jet experienced several high profile crashes and it remained a mystery as to the real cause. In 1954 one disintegrated in mid air near Elba, another broke apart during a flight near Calcutta.

 

It was determined during one investigation that stress fractures in the fuselage near the window cutouts were the primary cause. Stresses became so great after numerous take offs and landings the cabin pressures would blow out these cracks. If you look at jet windows closely note that they are more oval shape than square like the Comet. Designers learned a lesson due to real life experience. These air disasters basically destroyed DeHavilland as a major competitor in commercial jet manufacturing.

 

With any technology there's a lot more trial and error than we'd like to admit. What may be fine in a computer simulation may not be in real life. Who's to say that the composites won't break apart after 1,000, 10,000 or more take offs, landings, and pressurizations over a few years or a decade or two? Truth is we are just going to have to trust the technology until real life experience proves otherwise.

[Luv2play]

KMEM, you said that the Aloha "convertible" incident involved the use of composites in the fuselage of the 737 but I had read that the accident was caused by metal fatigue. This was caused by over 70,000 takeoffs and landings in a period shorter than for many other airlines using the same aircraft, given the short routes in Hawaii. As a result of these findings, aircraft operators were ordered to inspect for metal fatigue more frequently especially in light of number of takeoffs/landings.

 

I seem to recall that another factor cited in a program I watched on TV several years ago was the humidity in the Hawaiian islands but this presumably would not have affected aluminum components.

 

I was just wondering what you based your comments about composites on concerning the Aloha incident.

[KMEM]

KMEM, you said that the Aloha "convertible" incident involved the use of composites in the fuselage of the 737 but I had read that the accident was caused by metal fatigue. This was caused by over 70,000 takeoffs and landings in a period shorter than for many other airlines using the same aircraft, given the short routes in Hawaii. As a result of these findings, aircraft operators were ordered to inspect for metal fatigue more frequently especially in light of number of takeoffs/landings.

 

I seem to recall that another factor cited in a program I watched on TV several years ago was the humidity in the Hawaiian islands but this presumably would not have affected aluminum components.

 

I was just wondering what you based your comments about composites on concerning the Aloha incident.

 

So, at least one person (you, L2P) does read my quasi-technical posts.

 

All of the things you mention did contribute to this accident. Humidity will affect any commonly used metal. Remember, any man made product is very busy trying to revert to its' natural state. Some people call that corrosion.

 

Actually, what Boeing was doing was using glue to hold the aluminum skins in place and that is primarily what failed. Strictly speaking I suppose that would not be a composite in today's sense and use of the word but it was a new process for an airliner at least to the extent it was used on this model.

 

Of course, Boeing would not call it glue but an industrial strength adhesive developed especially for this purpose. Glue to you and me.

 

Best regards,

KMEM

[KMEM]

AS-

 

When glass cockpits first arrived on the airline scene a commonly told and retold story circulating among pilots was: What is it doing now? What is it going to do next? How do we turn it off?

 

Best regards,

KMEM

[KMEM]

AVG-

 

I have always loved the movie with Jimmy Stewart depicting the story that you describe.

 

What you say is true. We are often (unwitting) test pilots, test passengers and test drivers of new and "improved" equipment. Once we get past accountants trying to save a few bucks by making the same part cheaper, we have to deal with marketing which wants to make the same product look different. It is amazing how often engineering has to try to "save" both of those departments (from themselves, if not from the buying public).

 

Best regards,

KMEM

[N.N.]

Humidity will affect any commonly used metal.

Titanium alloys are practically impervious to humidity. They hold up to seawater.

They may not be common in household use, but are certainly common in aviation.

(I know the original question was about aluminum, but you said "any commonly used metal".)

[MsGuy]

Thanks for link AdamSmith. That 1988 Airbus crash was the result of the type of programming oversight that is almost inevitable with complex systems. For my money, there's just too many unforseeable one off combinations of possible failures to take ultimate control of a plane away from the pilot. Maybe I'd have a different take on expert systems if my Internet Explorer didn't fuck up so often.

 

KMEM, you're the resident expert here. Do you have an opinion on this?

[KMEM]

NN-

 

If you are going to nitpick, then so will I. You said, "practically". Naturally, some materials are better suited for certain tasks than others. Yes, titanium is widely used in aviation and so is magnesium. They both have their own strengths and weaknesses. I am sure you see my general point. I take no offense if you don't.

 

MsGuy-

 

I agree with your assessment of computers. To this day I don't know how we made it to the moon and back with the equivalent of 7 Radio Shack computers.

 

The Airbus in question was indeed on a PR demo flight and managed to make it into the trees which made it forever known as the "chainsaw". Knowing how management likes to operate this will no doubt surprise you; the airplane was exonerated and the pilot blamed. The pilot WAS partly to blame as he pulled some circuit breakers in an attempt to "over ride" the computers running the aircraft. However, the aircraft still descended (uncommanded) into the trees in spite of anything the pilot tried to do.

 

Donald Douglas was a strong believer in complete control of an aircraft. He had control cables to the control surfaces long after others had gone entirely to hydraulics. Certainly a good thing but not necessarily cost effective, light weight or technologically advanced. Lockheed was an early believer in hydraulics. Boeing tried to be conservative and wait until most things were tried and tested before leaping on the bankwagon. As most can readily see, Airbus has gone off in an entirely new direction.

 

Now that Boeing has bought McDonald-Douglas and they have become the leading US manufacturer of aircraft I will now state a saying of many "old hands" and that is, if it ain't Boeing, I ain't going".

 

Best regards,

KMEM

[N.N.]

NN-

 

If you are going to nitpick, then so will I. You said, "practically". Naturally, some materials are better suited for certain tasks than others. Yes, titanium is widely used in aviation and so is magnesium. They both have their own strengths and weaknesses. I am sure you see my general point. I take no offense if you don't.

I am not sure I do get your point.

I would welcome a more complete statement so that I do.

 

Donald Douglas was a strong believer in complete control of an aircraft. He had control cables to the control surfaces long after others had gone entirely to hydraulics. Certainly a good thing but not necessarily cost effective, light weight or technologically advanced. Lockheed was an early believer in hydraulics. Boeing tried to be conservative and wait until most things were tried and tested before leaping on the bankwagon. As most can readily see, Airbus has gone off in an entirely new direction.

Please correct me if I'm wrong, but there are two things Airbus has used: fly-by-wire, and a certain degree of automation. It's the automation that caused the pitch-down maneuver in Qantas flight 72, not fly-by-wire per se. I draw the distinction because I don't think fly-by-wire is inherently less robust (although the industry has had more time to perfect other means).

 

Incidentally, I drive a 14-year-old car with throttle-by-wire.

[KMEM]

N.N.-

 

The original point that I was trying to make is that man made materials try to revert to their natural state. Iron and steel try to revert to iron ore via reacting with the atmosphere to include O2 and water, among other reagents. Some materials are more resistant to reversion than others. Otherwise, I was just taking your use of the word, "practically" to mean literally that titanium did react to humidity but not as much as some other materials. I am beating this to death but you did ask.

 

You are correct in that the programs in the Airbus computers have caused a certain kind of problem. However, fly by wire, if it fails, can cause the same magnitude of failure as a complete shut down of the computer(s) regardless of whether they have failed at all. Of course, that is why they have redundant systems and pathways.

 

None of these ideas would have been certified if they were all bad and wrong. New ideas sometimes need a little time to find any hidden flaws. Aviation historically has been very conservative which I am sure you can understand. Minor errors can lead to major consequences.

 

Best regards,

KMEM

[+ glutes]

another Airbus in the drink

 

http://www.cnn.com/2009/WORLD/meast/06/29/yemen.plane.crash/index.html

[KMEM]

I always hate to hear of catastrophic deaths but especially those involving aviation.

 

It is early in the investigation but I think this accident will not have much if any thing to do with Airbus. However, it does point to 2 things I have mentioned before; namely, choose your carrier of choice as wisely as you can and try to avoid flying with seriously inclement weather at your departure or arrival airport. I certainly acknowledge staying within these guidelines is not always easy or economically possible. Many on this MB have listed their airlines of preference and those posters obviously already are aware of the points I am making.

 

At first glance, this appears to be a weather related accident but I have not seen an official report, only the mass media one, so far. Sailors know this and pilots should also and that is wind IS weather, just like storms, snow, etc.

 

Best regards,

KMEM

[Guest zipperzone]

http://www.cnn.com/2009/WORLD/meast/06/29/yemen.plane.crash/index.html

 

It is miraculous that a 5 yr old boy was found alive, floating on wreckage. He'll remember that for the rest of his life, I'm sure.