Dear 777 Affectionate,

 

Now that the PIC of PMDG revealed that his team is established on a loooooong final torwards the release, I was wondering what are the differences between the 777 fly by wire and the airbus one ?

 

Best

 

Karim

The major difference I presume is the fact that the Airbus birds have implemented pronounced limitations to their fly-by-wire system while Boeing goes the traditional route with their 777 by implying that the Pilot should be the one with the final decision.

The FBW of the 777 is very well explained here:

 

http://www.davi.ws/a...book_Cap_11.pdf

 

Airbus flight control laws are here:

 

http://www.airbusdri...bus_fltlaws.htm

 

You might also read this thread treating the same subject:

 

http://forum.avsim.n...fbw-on-the-777/

 

Guy

The major difference I presume is the fact that the Airbus birds have implemented pronounced limitations to their fly-by-wire system while Boeing goes the traditional route with their 777 by implying that the Pilot should be the one with the final decision.

 

The T7 has the standard stick and rudder controlling the aircraft. The only part of the T7 that is FBW are the spoilers if I remember correctly.

 

The software engineers should not see the Airbus FBW protections in normal operation. But I would absolutely love to see an A320 do what Tex Johnston did on the 367.

The T7 has the standard stick and rudder controlling the aircraft. The only part of the T7 that is FBW are the spoilers if I remember correctly.

This is incorrect. All control surfaces are fly-by-wire. Have a look at the post above yours and it's on the second page in that link.

You have asked a simple question that has a complex answer. I suggest that a good starting place to find the begiinings of an answer is http://www.smartcockpit.com/aircrafts-models.html

 

Perhaps you could post your findings here so that we can all share your findings?

 

Have a good Christmas.

Cheers, Richard

But I would absolutely love to see an A320 do what Tex Johnston did on the 367.

 

Pilots can disable the protections if they really wanted to but as mentioned they won't kick in unless the aircraft is in serious danger such as nearing a stall.

All,

 

Thanks a lot for the replies and pointing out some reaaaaally interesting reading material. Simplifying the matter: it looks like the 777 FBW is designed to feel like analogue controls. The computer is here to help the pilot to stay within a safe flight envelop or kick in when for example the plane is experiencing trust dissymmetry.

The airbus FBW, apart from its duty to protect the plane from slipping outside the flight envelop also assist the pilot by auto trimming the plane: the pilot just has to point where he wants to go and the computer will do the rest. Quite a change vs. the normal feeling of hand flying a plane.

 

I wish you a Merry Christmas.

 

Regards

 

Karim

Simplistically... if an Airbus pilot wishes to disable flight envelope protection, switches must be thrown on the overhead. Even then, you can't fully disable flight envelope protection.

 

However, a T7 pilot, by implementing extreme yoke force can override the Boeing flight envelope protection.

 

Can't wait for the PMDG T7 to be released. Nobody simulates an aircraft for FSX like PMDG

 

And a Christmas thanks to the PMDG team, for providing us with exemplary add-ons, and first rate customer support. :p0504:

Simplistically... if an Airbus pilot wishes to disable flight envelope protection, switches must be thrown on the overhead. Even then, you can't fully disable flight envelope protection.

 

However, a T7 pilot, by implementing extreme yoke force can override the Boeing flight envelope protection.

 

Can't wait for the PMDG T7 to be released. Nobody simulates an aircraft for FSX like PMDG

 

And a Christmas thanks to the PMDG team, for providing us with exemplary add-ons, and first rate customer support. :p0504:

 

I'm pretty sure an Airbus pilot can manually switch to direct law, which disables any and all protections and will make the flight controls behave exactly like in a 'regular' plane.

 

I'd like to note here that the flight envelope is not some kind of mythical thing that you can fudge a bit if you are a steely-eyed superpilot. When the plane's wing reaches the critical angle attack (i.e. you've reached the end of the flight envelope) it will stall. This is caused by the laws of physics, and will happen no matter how big your Ray-ban sunglasses are. 'Pushing the edge of the envelope' means performing carefully preplanned test flights to find out exactly where the flight envelope is, in order to check and improve your calculations and wind-tunnel experiments. It's something you want to do under carefully controlled flight conditions, not during some in-flight emergency.

Take a look at the ITVV 777 DVD:

 

http://www.itvv.com/product/B777/cpab777200dvd.html

 

Some of the 777 FBW Features are demonstrated in the simulator.

 

 

Jan-Paul

The major difference I presume is the fact that the Airbus birds have implemented pronounced limitations to their fly-by-wire system while Boeing goes the traditional route with their 777 by implying that the Pilot should be the one with the final decision.

Airbus limits are as far as any pilot should need to push the envelope. Absolutely no point in pulling angle of attack beyond CLmax for example. Also it's hard to see why a pilot of an airliner would want to command a bank angle above 67 deg.

 

In normal operation you don't go anywhere near the limits in either Airbus or 777. However in both cases the FBW modifies the response to pilot inputs. For example in a turn less than about 30 bank FBW will maintain pitch without the pilot pulling on the stick.

fly by wire means that the flight controls are not directly connected to the control surfaces.. but you can have fly by wire with no protections and have it operate exactly like traditional controls. I think some people confuse how Airbus handles pilot input as a characteristic of all fbw aircraft

 

 

The FBW of the 777 is very well explained here:

 

http://www.davi.ws/a...book_Cap_11.pdf

 

Airbus flight control laws are here:

 

http://www.airbusdri...bus_fltlaws.htm

 

You might also read this thread treating the same subject:

 

http://forum.avsim.n...fbw-on-the-777/

 

Guy

 

This is very useful and is going on my ipad ASAP! Thanks a million!

Airbus limits are as far as any pilot should need to push the envelope. Absolutely no point in pulling angle of attack beyond CLmax for example. Also it's hard to see why a pilot of an airliner would want to command a bank angle above 67 deg.

 

I think my main issue with it is that the automatics are only as good as they're designed and written. The people writing the software can't think of every single contingency. The likelihood that you'd ever run into that issue is extremely slim, but I'd prefer to have the ability to kill the automatics if I believe it would save my life. I've spent too much time around computers, and doing my own programming, to simply place my life in the hands of it.

 

I do believe that it's made too much of an issue, in that 99.99999999999999998% of the time, it's a non-issue. I do believe, however, that sometimes you have to get inventive when things go terribly wrong. I can't tell you what that situation would be, though, and that's why I believe that the automatics wouldn't know how to handle it, either.