Unlike Airbus, Boeing lets aviator override fly-by-wire tech

[darthpanda]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

I think I'd rather have a pilot in charge of the final say; Machines can fail and we need a human brain to make a judgement call when that happens.

I do think fly by wire will open up flight to a lot of people that simply don't have the ability now. I know it might sound shocking, but imagine a day when the average person can get into an aircraft and fly around without worrying about collisions with other craft, obstacles, or the ground. It could take off, land, etc. Just direct it around and fly without worrying about navigating, etc. If you offload these worries to a system you may be able to facilitate this. Maybe.

I'm building a small "UAV" myself from off the shelf parts and writing the code for it and FBW is an interesting topic for me. I'd like to one day build an R/C airplane, a toy, that a kid could fly and be assured it will try it's best not to crash, so younger kids could take the controls and it will assist with avoiding the ground and stalling, etc.

 

[Orange Anchor]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

I think I'd rather have a pilot in charge of the final say; Machines can fail and we need a human brain to make a judgement call when that happens.

I do think fly by wire will open up flight to a lot of people that simply don't have the ability now.

My tailwheel instructor said the same thing about airplanes with nosewheels.

And so you don't want to fly anything with a FADEC (computer rheostat) for engine control.

 

[darthpanda]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

My tailwheel instructor said the same thing about airplanes with nosewheels.

And so you don't want to fly anything with a FADEC (computer rheostat) for engine control.

Let's not get into ridiculous absolutes. I meant that I want a pilot in charge of final decisions regarding piloting of the aircraft. Abstraction is a fact of life in an airplane because they are so complex. But I still want a human in charge ultimately. Just because my car uses computer-controlled injection doesn't mean I give it authority to change the throttle position on it's own.

Although I do think computer control of an aircraft is more significant than a change to a plane's wheel configuration, I do see what you mean. It's kind of a "yeah, sure" idea. Yeah sure, it might happen. I won't hold my breath or anything though. :beer:

 

[seagull]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

The story originally posted gave an example of the 747 pulling 4 g's to recover. Can't due that in an Airbus. I pick Boeing.

What makes you think you can't? If you exceed the hard limits do to a outside factor, the aircraft should revert to direct law, giving you that authority to recover. Even so, it is unlikely you NEED 4 g's to recover. Certification max puts design ultimate load at 3.75, so there is a fair chance that you will pull the aircraft apart at 4 g's.

In addition, what is the PROBABILITY of needing this, as opposed to the PROBABILITY of a loss of control scenario?

 

[seagull]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

The FedEx flight that was hijacked out of MEM. The captain exceeded design limits to get the plane back on the runway safely.

It was the F/O, actually, and it is not clear that was the best course of action. In addition, the PROBABILITY of something like that occurring is extremely low, so making it less safe in a more likely scenario to cover that sort of event is not very wise thinking.

Finally, do YOU have aerobatic experience? How about such experience in a swept wing jet (yes, it is different for several reasons)? Both front seaters on FedEx 705 did have such experience. Someone that did not would likely not survive the attempt. Until we are training for this, arguing that you should have the capability to do it is a bit silly. You are really just arguing for the aircraft to allow you to kill yourself.

Now, if we are going to put all transport pilots through real upset recovery training and aerobatics, I might agree with you!

 

[seagull]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

Let's not get into ridiculous absolutes. I meant that I want a pilot in charge of final decisions regarding piloting of the aircraft. Abstraction is a fact of life in an airplane because they are so complex. But I still want a human in charge ultimately. Just because my car uses computer-controlled injection doesn't mean I give it authority to change the throttle position on it's own.

Although I do think computer control of an aircraft is more significant than a change to a plane's wheel configuration, I do see what you mean. It's kind of a "yeah, sure" idea. Yeah sure, it might happen. I won't hold my breath or anything though. :beer:

FADEC DOES make final decisions regarding how much power you get. You absolutely cannot get the amount of overboost you used to be able to get. Even the soft limit alternate modes offer more protection than a mechanical fuel controller (the latter of which is more akin to your car's fuel injection system).

 

[msmspilot]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

While pilots may WANT the ability to exceed limits, give me an example of when you would use it? Just one? There really is no scenario that it should be used that has any sort of reasonable probability of occurring.

It was the F/O, actually, and it is not clear that was the best course of action. In addition, the PROBABILITY of something like that occurring is extremely low, so making it less safe in a more likely scenario to cover that sort of event is not very wise thinking.

Finally, do YOU have aerobatic experience? How about such experience in a swept wing jet (yes, it is different for several reasons)? Both front seaters on FedEx 705 did have such experience. Someone that did not would likely not survive the attempt. Until we are training for this, arguing that you should have the capability to do it is a bit silly. You are really just arguing for the aircraft to allow you to kill yourself.

Now, if we are going to put all transport pilots through real upset recovery training and aerobatics, I might agree with you!

Your first question (emphasis added): I supplied one.

Second, it was the F/O that rolled the plane, but the captain pulled enough G's to pop rivets coming from base to final. Both exceeded the design limits of the plane. Whether they should have or not... they made it home.

You're right that we're not training for this, but you asked for an example, I provided one. End of story. If you give an open ended "give me one example" and I give a real life example, you can't come back with "that one doesn't count" when it's exactly what we're talking about.

 

[Orange Anchor]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

Let's not get into ridiculous absolutes. I meant that I want a pilot in charge of final decisions regarding piloting of the aircraft. Abstraction is a fact of life in an airplane because they are so complex. But I still want a human in charge ultimately. Just because my car uses computer-controlled injection doesn't mean I give it authority to change the throttle position on it's own.

A FADEC is much more than merely the throttle position. It is FULL AUTHORITY digital engine control as in FULL authority. It decides what you get for thrust and it LIMITS how much thrust you can get out of that engine. On the marvelous old JT8D you could shove the throttles way past 100%. FADEC? Nope.

Although I do think computer control of an aircraft is more significant than a change to a plane's wheel configuration, I do see what you mean. It's kind of a "yeah, sure" idea. Yeah sure, it might happen. I won't hold my breath or anything though. :beer:

My point is pilots have been grousing about flight controls and handling since they removed one wing and the wires. And each group can find instances and accidents to prove THEIR point.

 

[seagull]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

Your first question (emphasis added): I supplied one.

Second, it was the F/O that rolled the plane, but the captain pulled enough G's to pop rivets coming from base to final. Both exceeded the design limits of the plane. Whether they should have or not... they made it home.

You're right that we're not training for this, but you asked for an example, I provided one. End of story. If you give an open ended "give me one example" and I give a real life example, you can't come back with "that one doesn't count" when it's exactly what we're talking about.

Not quite, as you did not cover the second line of what I wrote, which was the bold section below:

While pilots may WANT the ability to exceed limits, give me an example of when you would use it? Just one? There really is no scenario that it should be used that has any sort of reasonable probability of occurring.

That bold section is critical to this discussion. We might as well design aircraft to survive meteor strikes if we are going to chase things that have probabilities of less than 10^-8th!

 

[trafficinsight]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

A FADEC is much more than merely the throttle position. It is FULL AUTHORITY digital engine control as in FULL authority. It decides what you get for thrust and it LIMITS how much thrust you can get out of that engine. On the marvelous old JT8D you could shove the throttles way past 100%. FADEC? Nope.



My point is pilots have been grousing about flight controls and handling since they removed one wing and the wires. And each group can find instances and accidents to prove THEIR point.

It should mean it's up to the computer to decide how to give you 100% when you ask for 100% but not that the computer should be able to decide to give you 20% when you ask for 100% because it thinks 100% is too much.

That's how I see this argument.

In the airshow crash the computer decided the limits based on the mode it was in and the pilot disagreed... the computer won. Did the pilot screw up to put himself in that position? Sure, but when the computer says "nuh uh, we're landing," and you can't say "uh, doubt it." You lose.

Put in all the computerized assistance you want, I say, but make sure there's always an OFF mode.

 

[intern_mike]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

I think it basically comes down to the fact that computers know indisputably the limits of the flight envelope, where as the pilot has an opinion, which could very well be correct, but can still be wrong. It virtually eliminates accidents due to pilot error.

While I initially felt the Airbus' system undermined the skill and experience of the pilot, I now feel it is indispensable for safety. Which after all is the most important thing. The pilot should never be hindered by the computer because he should never need to push it to that level to begin with. And if he does, he can rest assured that the plane will give him all it has within the envelope of safety.

 

[flyinawa]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

It should mean it's up to the computer to decide how to give you 100% when you ask for 100% but not that the computer should be able to decide to give you 20% when you ask for 100% because it thinks 100% is too much.

That's how I see this argument.

In the airshow crash the computer decided the limits based on the mode it was in and the pilot disagreed... the computer won. Did the pilot screw up to put himself in that position? Sure, but when the computer says "nuh uh, we're landing," and you can't say "uh, doubt it." You lose.

Put in all the computerized assistance you want, I say, but make sure there's always an OFF mode.

I assume you're talking about the airshow crash in France when they ran the 320 through the trees at the end of the runway. Your conclusions are wrong because your facts are wrong.

Captain Bonjour had the thrust in idle to do the low approach *(way below the approved altitude, by the way) and he was WAY too late firewalling the thrust. The engines just started to spool up as he hit the trees. Watch the video. NO jet aircraft could have avoided going into lawnmower mode. What makes the Airbus special is it gave him the MAX AOA the wing could produce without stalling. Another degree and she would have rolled over on her back and everyone would have died.

http://www.youtube.com/watch?v=wBFG3_y6zIg

 

[Minuteman]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

I reaaaaallly wish we knew more about what happened with Air France 447.

 

[TUCKnTRUCK]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

I wonder how UAL 232 would have turned out in an airbus...

 

[Orange Anchor]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

In the airshow crash the computer decided the limits based on the mode it was in and the pilot disagreed... the computer won. Did the pilot screw up to put himself in that position? Sure, but when the computer says "nuh uh, we're landing," and you can't say "uh, doubt it." You lose.

Put in all the computerized assistance you want, I say, but make sure there's always an OFF mode.

Wrong. Simply wrong. Although the idea persists and focuses on the computer, many simply do not know or remember the CFM-56 at that time was KNOWN for a slow spool-up. Put the engine in idle and then go max thrust and as I remember it was acceptable for response to take up to 7-9 seconds.

The computer (nefarious sounds not added) did not make any decisions based on "we're landing" and refuse to go around. One only has to stop and think about such a ludicrous assertion. Would the FAA EVER certify an airplane that would do that? Not likely.

Finally, computers, no computers. It really isn't the issue. What we see (or did see in the tng dept) was a lack of understanding of what the airplane and systems were doing. We had a 767 going into a field and tower changed runways. The airplane was configured gear down, flaps to landing and the crew went heads down to reprogram the FMS. The airplane is on autopilot but now with no guidance. But it is happy and all conditions are met for a landing. Descent rate is not excessive. The airplane is configured. The crew finally looks up and according to different stories they were below 1000ft AGL miles from the runway. They powered up and climbed up and landed. Now here's the funny part. The crew did nothing. NO NASA. No incident report. Nothing. And nothing happened until residents began calling asking why there was a 767 in their backyard. The saving grace was ATC never called the crew low on the approach.

There are three states of proficiency or exposure to highly automated airplanes
first 1-6 months "What's it doing now?"
second 6 months, "I've NEVER seen that before!"
12-18 months "Yeah, it does that some times."

 

[Orange Anchor]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

I wonder how UAL 232 would have turned out in an airbus...

In some ways, that accident was repeated when DHL took a missile out of Baghdad. And even more amazing is the composition of the crew (3 different nationalities with English being a second language to all as I remember.. could be wrong on that one)

(I had forgotten a news team was with the bad guys watching them fire the missile)

http://sleetapawang.spaces.live.com/blog/cns!BD09644C5F6E196D!969.entry

Airbus later had a detailed ppt on the incident. Note:all hyd gone!

More photos of the damage (note the IL76 in the background of one photo and the nosewheels OFF the ground. Good comps on the CG)
http://www.fredhoot.com/DHLairbus.html


Anyway, the A-300 (not FBW) landed with most systems gone. Amazing feat of airmanship.

As for FBW, with ALL computers down and with all ELECTRICITY gone, the 'bus has a trimmable horizontal stabilizer, connections to the rudder and (gasp) the engines still have their FADECs. But it would be sheer speculation and a morass to try to make any points comparing the two.

 

[seagull]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

I assume you're talking about the airshow crash in France when they ran the 320 through the trees at the end of the runway. Your conclusions are wrong because your facts are wrong.

Exactly. Many like to bash FBW based on urban myth on what FBW can, and cannot do!

 

[seagull]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

I reaaaaallly wish we knew more about what happened with Air France 447.

We all do, but it is most probable that the accident was not related to FBW, other than the fact that the aircraft flight controls happen to use that system.

 

[seagull]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

I wonder how UAL 232 would have turned out in an airbus...

The design of the DC-10 (since modified) contributed to the single point of failure for all hydraulic systems, not so much different than the "kill zone" on the F-4, which was also later modified.

FBW still uses hydraulics to move the panels, so having a FBW system on the -10 would not have made any difference. Incidentally, the autopilot on the -11 also uses FBW, which does provide a nice backup to the cable system should there be a problem in that regard.

 

[trafficinsight]

Re: Unlike Airbus, Boeing lets aviator override fly-by-wire

Wrong. Simply wrong. Although the idea persists and focuses on the computer, many simply do not know or remember the CFM-56 at that time was KNOWN for a slow spool-up. Put the engine in idle and then go max thrust and as I remember it was acceptable for response to take up to 7-9 seconds.

The computer (nefarious sounds not added) did not make any decisions based on "we're landing" and refuse to go around. One only has to stop and think about such a ludicrous assertion. Would the FAA EVER certify an airplane that would do that? Not likely.

Finally, computers, no computers. It really isn't the issue. What we see (or did see in the tng dept) was a lack of understanding of what the airplane and systems were doing. We had a 767 going into a field and tower changed runways. The airplane was configured gear down, flaps to landing and the crew went heads down to reprogram the FMS. The airplane is on autopilot but now with no guidance. But it is happy and all conditions are met for a landing. Descent rate is not excessive. The airplane is configured. The crew finally looks up and according to different stories they were below 1000ft AGL miles from the runway. They powered up and climbed up and landed. Now here's the funny part. The crew did nothing. NO NASA. No incident report. Nothing. And nothing happened until residents began calling asking why there was a 767 in their backyard. The saving grace was ATC never called the crew low on the approach.

There are three states of proficiency or exposure to highly automated airplanes
first 1-6 months "What's it doing now?"
second 6 months, "I've NEVER seen that before!"
12-18 months "Yeah, it does that some times."

Well I apologize for perpetuating a myth, it happens to all of us now and again.

My stance doesn't change though... all the computerized assistance you can pack in but it needs to have a manual mode for when things assume a heading of 180.