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He stepped on the Rudder and redefined Va

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He stepped on the Rudder and redefined Va

Old 2nd Oct 2013, 21:57
  #181 (permalink)  
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Let's take the NTSB report, word for word, and cull for what is being said. Word for word. I just cut and pasted...

NTSB Press Release
National Transportation Safety Board
Office of Public Affairs

OCTOBER 26, 2004

Washington, D.C. - American Airlines flight 587 crashed into a Queens neighborhood because the plane's vertical stabilizer separated in flight as a result of aerodynamic loads that were created by the first officer's unnecessary and excessive rudder pedal inputs after the aircraft encountered wake turbulence, according to a final report adopted by the National Transportation Safety Board today. The Board said that contributing to the crash were characteristics of the airplane's rudder system design and elements of the airline's pilot training program.

At about 9:16 a.m. on November 12, 2001, flight 587, an Airbus A300-605R (N14053), crashed in Belle Harbor, New York shortly after taking off from John F. Kennedy International Airport on a flight to Santo Domingo. All 260 people aboard the plane died, as did five persons on the ground. This is the second deadliest aviation accident in American history.

The aircraft's vertical stabilizer and rudder were found in Jamaica Bay, about a mile from the main wreckage site. The engines, which also separated from the aircraft seconds before ground impact, were found several blocks from the wreckage site. The Safety Board found that the first officer, who was the flying pilot, inappropriately manipulated the rudder back and forth several times after the airplane encountered the wake vortex of a preceding Boeing 747 for the second time. due to The aerodynamic loads placed on the vertical stabilizer he sideslip that resulted from the rudder movements were beyond the ultimate design strength of the vertical stabilizer. (Simply stated, sideslip is a measure of the "sideways" motion of the airplane through the air.)

The Board found that the composite material used in constructing the vertical stabilizer was not a factor in the accident because the tail failed well beyond its certificated and design limits.

The Safety Board said that, although other pilots provided generally positive comments about the first officer's abilities, two pilots noted incidents that showed that he had a tendency to overreact to wake turbulence encounters. His use of the rudder was not an appropriate response to the turbulence, which in itself provided no danger to the stability of the aircraft, the Board found.

The Board said that American Airlines' Advanced Aircraft Maneuvering Program contributed to the accident by providing an unrealistic and exaggerated view of the effects of wake turbulence on heavy transport-category aircraft. In addition, the Board found that because of its high sensitivity, the A300-600 rudder control system is susceptible to potentially hazardous rudder pedal inputs at higher speeds. In particular, the Board concluded that, before the crash of flight 587, pilots were not being adequately trained on what effect rudder pedal inputs have on the A300- 600 at high airspeeds, and how the airplane's rudder travel limiter system operates.

The Safety Board's airplane performance study showed that the high loads that eventually overstressed the vertical stabilizer were solely the result of the pilot's rudder pedal inputs and were not associated with the wake turbulence. In fact, had the first officer stopped making inputs at any time before the vertical stabilizer failed, the natural stability of the aircraft would have returned the sideslip angle to near 0 degrees, and the accident would not have happened. (The Board estimated that the sideslip angle at the time the vertical stabilizer separated was between 10 and 12.5 degrees.)

The NTSB issued eight recommendations in today's report. Among the seven sent to the Federal Aviation Administration were those calling for adopting certification standards for rudder pedal sensitivity, modifying the A300- 600 and A310 rudder control systems to increase protection from potentially hazardous rudder pedal inputs at high speeds (a similar recommendation was issued to the French equivalent of the FAA, the DGAC), and publishing guidance for airline pilot training programs to avoid the kind of negative training found in American Airlines' upset recovery training.

Because this crash occurred two months after the September 11 terrorist attacks, there was initial concern that it might have been the result of an intentional criminal act. The Board found no such evidence, nor did any law enforcement agencies provide evidence that the accident may have stemmed from criminal conduct. The Board said that witnesses who reported observing the airplane on fire were most likely observing misting fuel released from broken fuel lines, a fire from the initial release of fuel or the effects of engine compressor surges.

A summary of the Board's report may be found under "Publications" on the agency's website at NTSB - National Transportation Safety Board. The full report will appear on the website in about four weeks.

Last edited by Teldorserious; 3rd Oct 2013 at 02:32.
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Old 2nd Oct 2013, 22:08
  #182 (permalink)  
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I don't think that the A300 is a bad airplane... one DHL survived a SAM attack and was controllable enough to fly on engine power as a sole means of control...to me that says something about that plane...the flight controls aren't designed to take the stress of rapid large flight control oscillations. In the case of the VS the torque moment is tremendous well above certification...

As an aside Vp which is Va based upon stall is Vs*(nlimit)^0.5 but since stall speed increases with weight the actual maneuver speed is not a constant
An accelerated stall above Vp would impart a force that is above the limit load
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Old 2nd Oct 2013, 23:09
  #183 (permalink)  
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"the NTSB is full of humans...humans make mistakes...we have our opinions based on years of whatever we have been doing"

Yes Flarepilot, humans do make mistakes so it's just possible that the FO made a mistake.

NTSB I presume consists of more than one person so a "human mistake" is more likely to be picked up by them than a human mistake would be picked up in the dynamic cockpit of an airliner.

"I"ve flown with engineering types who had commercial or atp lic. get em talking and they would fly right into the side of a mountain or stall the plane...I've seen it."

Flarepilot: Your comment above is interesting and I wonder if you could clarify the following:

1. When you were flying with "engineering types" how did you survive flying into a mountain?

2. If you observed a plane flying into a mountain, how did you know that the pilot flying was an"engineering type"?

3. If you are unable to answer 1 or 2 above, might it not be better to delete "I've seen it" and replace it with something along the lines of "That is what I suspect would happen"

As a simple soul am trying to understand your reasoning and sadly failing to do so. Therefore am hoping that your reply to the above three points will for me clarify your position.

Last edited by Nick Thomas; 2nd Oct 2013 at 23:10. Reason: Punctuation
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Old 2nd Oct 2013, 23:12
  #184 (permalink)  
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I had an FO when flying the B727 that over controlled every landing with PIO's.

I flew with him years later in the B757 and he was the ace of the base. He was smooth and way ahead of the airplane. I still think the captain who complained about his rudder usage got too much input to the NTSB. Everyone goes through a learning process going to a new airplane. I know, I didn't fly the A300 because I didn't trust it like a Boeing. Had no problems because they are so straight forward to fly. The extra pay wasn't worth it for me.
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Old 2nd Oct 2013, 23:26
  #185 (permalink)  
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forgive me nick thomas I was speaking in pilot slang...I realize that we are separated by a common language but I am assuming (possibly incorrectly) that my fellow pilots are the ones reading this forum.

I watched engineers who were so interested in talking about the engineering of the plane (while they were pilot handling) that they lost track of their airspeed and approached the stall (aerodynamic stall that is) and I had to remind them TO KEEP THEIR SPEED UP; (up , meaning in a safe range)>

And while they were under the hood (simulating instrument flight) they were speaking of engineering so much that they LOST SITUATIONAL AWARENESS and turned the wrong way on the BACK COURSE OF A LOCALIZER and were proceeding in the direction of a LARGE FRICKING MOUNTAIN RANGE...I again spoke up correcting their error.

I do hope this clarifies...we don't speak as if we are talking to the Queen...we speak like we are talking to fellow PILOTS.

NO, they weren't allowed to hit the mountain or stall the plane...I stopped them. Again, speaking in a manner that a pilot who has flown for many years might speak to a fellow pilot of similar background.

May I translate anything else for you?

And yes, maybe the first officer did crash the plane...but it is my opinion the plane failed the crew, the crew didn't fail the plane.
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Old 2nd Oct 2013, 23:41
  #186 (permalink)  
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It is odd how so many people live in denial of reality.

One poster refuses to believe that a vertical stabilizer can be broken off an airplane despite engineering evidence that this is exactly what can happen and why we now have warning not to make certain inputs on certain aircraft.

Others refuse to believe that a pilot made repetitive inputs on his rudder pedals despite direct evidence of it having been done as recorded on an FDR. Excuses such as yaw damper are thrown about despite that being impossible.

All of which reminds me of the Egyptair investigation and more recently the Ethiopian crash in Beirut. Fortunately for us in the west, we have a much smaller percentage of believers in theories that fly in the face of the obvious.

There may be other factors to consider such as how light a force is required on the pedals to get full deflection but that doesn't change the other evidence.

Last edited by JammedStab; 2nd Oct 2013 at 23:42.
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Old 2nd Oct 2013, 23:51
  #187 (permalink)  
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pilot how did the plane fail them when the were doing a maneuver outside of certification? I think their training in wake encounter recovery failed them i feel bad for the flight crew and I don't really blame them as the copilot was simply doing what he was taught ...
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Old 2nd Oct 2013, 23:52
  #188 (permalink)  
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Thank you for your prompt reply.

I understand why you assume you are speaking to pilots.

I am of course not a commercial pilot yet I have a keen interest in aviation as I have in many other fields.

As an Architect I am interested in the design and construction of aeroplanes. In keeping up with aviation design I have learnt many things that are useful in my practise of Architecture.

I have found that keeping an open mind and not judging things on face value has also been helpful in my Architectural development.
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Old 2nd Oct 2013, 23:58
  #189 (permalink)  
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animus...if the pilot knew the plane would fall apart if he did, "X" then he would not have done, "X".

But the authority that certified the plane, pilots, airline and training didn't bother to make sure the pilot knew that "X" would cause the plane to fail.

so I don't blame the pilot...at worst I blame the system equally along the way...

NICK THOMAS...an architect...that's great. You might really enjoy reading, "Sliderule" by Nevil Shute (norway).

As a matter of fact, you might gain keen insight into my views about airplane structure by reading, or viewing the movie version of, "NO HIGHWAY" (sometimes known as "NO HIGHWAY IN THE SKY). Hope you do both.

You might even recognize the keen defense of the pilot in this book and how it does turn out to be the FREAKING AIRPLANE and not the pilot.

Do read them both and get back to me.
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Old 3rd Oct 2013, 00:35
  #190 (permalink)  
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Flarepilot I believe that general ignorance of operating strength limitations is very widespread...this is something that should be covered in primary training...obviously the FO didn't understand that because he was not taught. In fact my belief is that there was a systemic failure...more emphasis needs to be placed on operating strength limitations in general, there are lots of pilots who don't understand the limitations simply because they were never taught...the fact that the FAA approved such a syllabus is appalling and therefore I agree that the FAA should shoulder some of the blame. When Bob Hoover reverses his side slips back and forth he's going very slow he doesn't break the plane because he understands the limits
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Old 3rd Oct 2013, 00:51
  #191 (permalink)  
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It is well understood by the engineering pilots around that there is a great problem with pilot education when it comes to what the certification animal does as contrasted with the line flight standards animal.

Fact of life and it is going to be a long while, if ever, before the typical pilot's knowledge base is lifted to the point where he/she has a basic idea of certification stuff.

.. which is why this Forum is so important. We have a bunch of very well credentialled

(a) line, training, check pilots

(b) TPs and FTEs

(c) certification, design, test engineers, aerodynamicists etc

(d) many anciliary specialists in airports and a host of other disciplines

The problem is that, sometimes, it can be difficult to sort the wheat from the chaff when posters are anonymous but that's a small problem overall as the more experienced folks offer comments (not always as subtle as might be desirable) which provide clues ...
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Old 3rd Oct 2013, 01:10
  #192 (permalink)  
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In my "line" experience, there is a common belief that the standards have fairly wide margins and using some of that margin is OK. Without certification or performance engineering experience, many don't comprehend how limited those margins are and how easily one can go from inside the envelope to way outside of it.

Last edited by galaxy flyer; 3rd Oct 2013 at 01:10.
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Old 3rd Oct 2013, 01:15
  #193 (permalink)  
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If our A300 going out of control with yaw damper movements at 140 knots into MIA had happened at 250 knots would the VS had departed? Probably. I still stand with the FO that he didn't cause it no matter what NTSB came up with.
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Old 3rd Oct 2013, 01:20
  #194 (permalink)  
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pugilist animus

if you believe what you wrote, what is the problem of putting a placcard in front of the pilot saying: don't wiggle the rudder back and forth too much or the plane will fall apart...or any language you like to express this?

I have placcards right now telling me gear speeds, flap speeds and not to do a CAT II Ils if the equipment isn't working.

of course a placard that says the plane will fall apart will likely be bad for public relations
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Old 3rd Oct 2013, 01:28
  #195 (permalink)  
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One would have to placard all airplanes...it's better that the placard be in the pilots mind just as stall recovery should be.
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Old 3rd Oct 2013, 01:37
  #196 (permalink)  
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then how about control limiters to make sure pilots don't over control?

and a placard is pretty cheap insurance until all pilots have been trained.
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Old 3rd Oct 2013, 01:58
  #197 (permalink)  
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Flare even with rudder ratio limiting the certification standards do not cover large control reversals... placarding would simply be a bandaide on a gunshot wound...why not placard stall recovery also? Only education can militate against a repeat of AA 587
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Old 3rd Oct 2013, 02:10
  #198 (permalink)  
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or better built planes puglist

and if you want a placard for stall recovery, I'm sure Air France will lead the way in placing the placard on their airbus fleet.

and I'll take a band aid any day...its better than an open wound.

by the way puglist

one plane I flew says don't move control wheel more than half way above FL400

now certainly I know that, but there is a placard...

oh maybe there should be one of those on the A300 too
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Old 3rd Oct 2013, 02:33
  #199 (permalink)  
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I suppose for now that PPRuNe serves as a placard, I hope
As far as "better planes" go, the weight of reinforcing the VS to survive such abuse would be prohibitive
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Old 3rd Oct 2013, 07:49
  #200 (permalink)  
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As illustrated in tdracer's post #100, and testified in the FAA's Final Rule on the matter, the 'placard' is now in the Airplane Flight Manuals of all transport category airplanes flying in the US.
The private citizen noted the proposed amendment is not retroactive, so it would not fix the problem for existing aircraft.
Although the proposed amendment would not be retroactive, the FAA has worked with airplane manufacturers to amend their AFMs for all major transport category airplanes used in U.S. operations. The wording now in the limitations section of these AFMs meets the requirements of this final rule.

Last edited by HazelNuts39; 3rd Oct 2013 at 08:09. Reason: quote added
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