Boeing plans 787 increase

reply to post by luxordelphi


Not a huge fan of wikipedia but here is there take on Flight 587

Here is the NTSB summary

Contributing to these rudder pedal inputs were characteristics of the Airbus A300-600 rudder system design and elements of the American Airlines Advanced Aircraft Maneuvering Program.

It directly pointed to incorrect training and pilot error in applying the rudder as aggressively as he did in the Airbus 300-600 and its fly-by wire system.

Zaph already pointed out that such actions created an unstable oscillation in the vertical stabilizer that ultimately led to the separation of it and doom of the aircraft. Zaph also pointed out that as speeds increase, less action is required on the rudder controls to obtain the movement desired. So a pilot hitting the rudder hard left then hard right over and over caused undue stress upon the air-frame.

Zaphod58

luxordelphi
Just another thought: wasn't there a rudder that fell off in flight (that was an Airbus) and was blamed on pilot error? Excessive rudder use was the official culprit, I believe. Maybe this panel was pilot error? Excessive fuselage panel use? And that's why escalated production is ok because no fix for this is possible except better training for pilots in fuselage panel use?

Seriously? Excessive panel use? Wow. And how exactly do you manage to accomplish that?

The rudder with Airbus is an interesting one, because the faster you go, the less rudder input you require. Flight 587 was climbing out, at best climb speed, and the copilot was using full rudder deflection. That led to pilot induced oscillations, which led to the entire vertical fin separating. The pilot in question had been counselled repeatedly on rudder use.

So is this like brake failure in a car - driver error...excessive brake pedal use? Pilot error for excessive fuselage panel use, to me, is just as funny as pilot error for excessive rudder use. Perhaps counseling the pilot on advanced composite catastrophic failures would have been more productive. And just how gingerly do we need to tread around these materials?

reply to post by luxordelphi


Are you serious? Boeing knows everything they can know about this plane, as does the FAA, and the NTSB. But if you want to hyperbole about how the FAA knows nothing about composites you go right ahead.

Every Airbus ever built uses composites, and had to be certified by the FAA if they were bought by a US carrier (which a lot were). That included repair plans. The only difference between an Airbus and the 787 is the Airbus doesn't use as much composite in it.

The 787 couldn't even be certified for first flight without repair plans, and test showing that certain systems weren't going to be a problem. All signed off by the FAA.

But you're right, no one has any idea what they're doing. That's why 200 flights a day are safely carried out every day. That's why the overall fleet has a 97% readiness rating. That's why they aren't falling out of the skies. Thank god Boeing certified their own airplane!

luxordelphi
Pilot error for excessive fuselage panel use, to me, is just as funny as pilot error for excessive rudder use. Perhaps counseling the pilot on advanced composite catastrophic failures would have been more productive. And just how gingerly do we need to tread around these materials?

First...what panel use is the pilot using? I am not sure you understand what is exactly being talked about here. Second, training was updated, in conjunction with the crash of Flight 587 in regards to the limits and characteristics of the Airbus 300's rudder system and its application.

This isn't about the materials, it was about piss-poor training and a First Officer who had a history of using excessive rudder action to stabilize during turbulence that led to failure. As for the fuselage panel...that is out of the pilots hands and is on the reliance of the ground crew to secure that portion of the aircraft prior to push back.

Zaphod58
reply to post by Mikeultra

 

The 787 maximum take off weight is 553,000 pounds. The wings are capable of handing 150% of the maximum stress that will ever be placed on them, which is the equivalent of falling straight down in flight, from 40,000 feet, to less than 10,000 feet in a matter of seconds.

I don't care if they look like a piece of paper. They are stronger than you can imagine.

Why don't you tell that person about how all the wing assembly had to be redone because originally (strong composite and all) the wings just fell off?

reply to post by luxordelphi


I'm still waiting to hear how you can have "excess panel use" when pilots don't open panels on the plane. And this was an aerodynamic fairing, which no one would open, at any point, unless they were working on something under it.

No, the rudders are nothing like brakes in a car.

Ok, let's go over this slowly.

Airbus has a fly by wire system in their planes (Boeing started it in the 777 family). At slow speeds (take off, and landing), you have to input a lot of rudder pedal. On a non-fly by wire aircraft, you have to input a lot of rudder pedal at all speeds.

On a fly by wire system, the faster you go, the less input is required. That means that at flight climb speeds, you go from pushing the rudder pedal three inches, to one inch, and get the same deflection on it.

If a pilot has never flown, or had little experience with a fly by wire system, he's going to continue to use three inches of rudder input, no matter what the speed is. That means that the rudder is going to slam to full deflection whenever he uses the rudder. If you do that in the situation they were in, where they had a lot of lateral force on the tail, because of wake turbulence, you make that lateral force a lot worse. This leads to the vertical fin (the tail), failing. Which leads to it coming off, and the plane losing all controllability. Which is exactly what happened.

reply to post by luxordelphi


Because they didn't "just fall off". They never fell off, at any point in testing, be it on the ground, or in flight (obviously).

Again, apparently you're confused. They had a problem with the center wing box that required redesign. And a problem with some fasteners that had to be replaced. At no point in time, EVER, did the wings "fall off".

luxordelphi
Why don't you tell that person about how all the wing assembly had to be redone because originally (strong composite and all) the wings just fell off?

You are speaking nonsense and out of your league honestly. I have a good knowledge of aircraft and my forte is more on the end of the separation of them in the sky and the equipment that assists in that; but what are you talking about?!

The wing box was tweaked, way prior to the certification of airworthiness of the frame so it holds no bearing to your argument. The problem was identified long before it was put into the market.

ownbestenemy
reply to post by luxordelphi

 

Not a huge fan of wikipedia but here is there take on Flight 587

Here is the NTSB summary

Contributing to these rudder pedal inputs were characteristics of the Airbus A300-600 rudder system design and elements of the American Airlines Advanced Aircraft Maneuvering Program.

It directly pointed to incorrect training and pilot error in applying the rudder as aggressively as he did in the Airbus 300-600 and its fly-by wire system.

Zaph already pointed out that such actions created an unstable oscillation in the vertical stabilizer that ultimately led to the separation of it and doom of the aircraft. Zaph also pointed out that as speeds increase, less action is required on the rudder controls to obtain the movement desired. So a pilot hitting the rudder hard left then hard right over and over caused undue stress upon the air-frame.

Thx. Just thought you might know on the fly by wire rudder - had thought that system was to stabilize aircraft automatically without pilot input. So the failure should have been attributed to an electronic malfunction which then caused excessive rudder input (although, again, not more excessive than certification tests showed it should have withstood.) Something not right there.

I'm glad I'll never fly in one of those planes. I would rather fly in something that can glide to the ground if something were to happen. I like cesna bi-wings myself, except if it's cold outside. You can't be in a hurry with those if you are going against the wind though. I was flying backwards when I was a student. The instructor said I had to increase altitude, I thought it was neat that I was hovering over the ground and still flying. Someone probably thought I was a UFO hovering there. I turned around and boy was I going fast in that little plane. Flying class can teach you a lot about planes when you actually go up with the instructor and experience it.

reply to post by luxordelphi


No fly-by-wire is a direct replacement of old hydraulic systems; not the automation of them.

No the problem was with the training that was given and pilot error. It is clearly documented and confirmed. Pilots were being taught to hit the rudders hard during wake-turbulence and particularly, the First Officer was an offender of utilizing that method. They failed to recognize the limits, capabilities and characteristics of the Airbus 300 in their training and it lead to a fatal accident. Nothing fishy at all.

reply to post by luxordelphi


No flight control stabilizes the plane without input. There's always some kind of input before a flight control moves. The rudder is to move the nose of the plane from side to side. At one point it was used for coordinated turns. You had to input the rudder as you rolled the wings. Now, new flight control computers make that less necessary. But you still need a way to turn the nose side to side.

There is nothing "fishy" about 587 going down.

reply to post by Zaphod58


Which is better: hyperbole or Pollyanna? I don't think it's up to Boeing to discover that for us.

Every Airbus ever built uses composites, and had to be certified by the FAA if they were bought by a US carrier (which a lot were). That included repair plans. The only difference between an Airbus and the 787 is the Airbus doesn't use as much composite in it.

Just a short explanation of my position: I am not a fan of advanced composites whether they be Boeing, Airbus or Schwinn or Jaguar or Portland cement.

Boeing built a plane that is 50 to 60% composite by weight and 70 to 80% by volume. They self-certified. Maybe the question here should be: whom do you trust?

reply to post by luxordelphi


They did not "self certify". Again, you are confused. NO aircraft manufacturer self certifies. They test, and they perform the tests and the results are verified by the FAA. The FAA certifies based on the test results, or has them retested, or can take them to their own labs for testing.

It doesn't matter if it's Boeing, Lockheed, Airbus, Piper, or whoever else you want to name. NO ONE self certifies an aircraft.

The FAA has observers on hand, at every point in the testing process. They even fly on the test planes with the engineering crews, to monitor flight testing. They usually have at least one in the back with the systems guys, and one in the cockpit with the flight crew.

Zaphod58
reply to post by luxordelphi

 

ieeecss.org...
www.nasa.gov...
sapilot.com/a320/otherfile/Airbus_FBY_Overview.ppsx (this one will download)
www.davi.ws...

Thx for these links - so that particular Airbus that lost its' rudder didn't have fly by wire? Or did it have some pre-digital, analog version?

reply to post by luxordelphi


All Airbus aircraft have fly by wire. They always have. That's why the rudder moved the way it did. With hydromechanical controls you have to push the rudder pedals fairly hard, and move the pedal several inches to deflect the rudder fully.

With fly by wire, the more speed, the less you push, and the more deflection you get. Which is exactly what happened.

reply to post by Zaphod58


Does the 787 have fuel tanks in its paper thin wings? Here is a 787 flown by an F18 pilot. It makes me nervous!

reply to post by Mikeultra


First of all they're not "paper thin" wings. They're stronger than they need to be.

Secondly that was at an airshow demonstrating the flight characteristics of the aircraft. It was flown with a light fuel load by their head test pilot. You can find similar videos of Airbus and other Boeing aircraft at various airshows.

As for the fuel tanks all aircraft have fuel tanks there. It's where the majority of the fuel is carried.

reply to post by Zaphod58


OK thanks for that info, it must not have big tanks then. The wings look too thin for my confidence. I'm not an expert though. I flew only twice, once on a DC-10 and once on an Airbus A320. I'm done flying now.

reply to post by Mikeultra



I don't know how many different ways to say this. The wings on the Dreamliner are not thinner than they should be. They exceed requirements for weight bearing.

Unless you are an aerospace engineer, or have a lot of experience on that type of plane, there's no way to just look and say, "that's not strong enough".

The 787-8, the one currently in service has a range of between 8800 and 9400 miles depending on load.