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737forever
28th Oct 2009, 19:50
How does the fly by wire system on the 777 work in a crosswind? Can you sideslip with cross control like a conventional aircraft or does a aileron input on the yoke just command a given roll rate.so that you have to neutrelaze the yoke once the give bank angle is achived?
And what is the normal way of doing it? I have seen both crab and wing low,but not sure what is the normal way of doing it.

zlin77
28th Oct 2009, 20:27
Flies just like a normal aircraft with crossed controls, control inputs must be maintained to displace the flight control surfaces....my preference is the sideslip in crosswinds, just as the auto-land function does, no dramas and smooth landings ,as the form drag does not change in the flare as can happen with the de-crab and popping a roll-spoiler with robust aileron inputs.

411A
28th Oct 2009, 20:38
...Flies just like a normal aircraft with crossed controls, control inputs must be maintained to displace the flight control surfaces....my preference is the sideslip in crosswinds, just as the auto-land function does, no dramas and smooth landings


Lockheed L1011..same/same, from 150 feet RH.
Works good, lasts a long time.
Next question...:}
Actually, there might be...the L1011 was certified from the factory to CATIIIA, from the get-go.
35 knots direct crosswind.
Done it...works good.:)
Thank you.

Spooky 2
28th Oct 2009, 23:43
411A, I'll have to take alook at my old manuals but I do not recall the autoland x-wind limit being as high as 35kts?

The 777 is 25 kts and that seems to be a Boeing fleet standard. Good for CATlllB with an engine out and 25 kts, if you have the nerve.

Max hand flown demonstarted xwind on the 777 is 38 kts.

And yes the airplane flys pretty much the same as other Boeings if not a little better with the FBW/PFC's doing there little tap dance:ok:.

411A
29th Oct 2009, 01:39
411A, I'll have to take alook at my old manuals but I do not recall the autoland x-wind limit being as high as 35kts?


Company specs, dry runways only, vis 1200 metres or more.
Wet runway, 25 knots.
CatIIIB, 15 knots max, as I recall.
Wing-down method used for touchdown, from 150 feet radio height.
Engine inop, same/same.

nitpicker330
29th Oct 2009, 02:38
Actually the 777 can Autoland up to the max limit of 38kts.

The limitations section mentions the 25 kts "when the landing weather minima are predicated on autoland operations"

If the weather is ok ( apart from a howling x/w ) then no problems!!

to quote the FCOM 3 limitations section:

Automatic Landing
# Maximum allowable wind speeds when landing weather minima are predicated
on autoland operations:
Headwind 25 knots
Tailwind 15 knots
Crosswind 25 knots
Note:
Crosswind limit applicable to actual LWMO on a non contaminated runway
only. Refer to L.10 ‘Aircraft General’ for other conditions.

This was brought up with Boeing and they confirmed it as written.

The Airbus FCOM 3 Llimitations is worded differently and as such Autolands are always limited to 35/20/10 components.

Spooky 2
29th Oct 2009, 14:25
Nitpicker, I can hardly wait for my next oral!! BTW, 15Kts tailwind is only if you have bought the 15Kts "Option" as opposed to the standard 10KTs.:ok:

Thanks,

411A, not sure how a company (in the US) sets standards that may exceed FAA cetification numbers??:confused:

411A
29th Oct 2009, 18:12
411A, not sure how a company (in the US) sets standards that may exceed FAA cetification numbers??

Simple, I don't fly in the USA, nor US registered aircraft.

You would be surprised what goes on elsewhere...even in UK/Europe...not to mention south of the Mediterranean.
\
NB.
The numbers I quoted were from SVA, when they operated L1011 equipment, and they operated to FAA regulations, with 'differences'.
SVA also have electronic moving map displays on all their TriStars (just forward of the throttles).
Deluxe...and they could afford same.

SOPS
29th Oct 2009, 21:34
We have a question about a 777, and good old 411 pops up again about the Tristar!!!! . Lord..give me strength................

Anyway..having never flown a Tristar.....but having several thousand hours on the 777, I can say it lands just like a "normal" aircraft when you fly it manually....in fact it flies normally all the time:ok:

Spooky 2
29th Oct 2009, 22:41
Clueless as to who SVA is? Moving map display? Wow... who would have thunk that. I'll trade twenty moving map displays for one simple EFIS.:}
TriStar is nice but way over the hill these days. I getting under the table for incoming.

john_tullamarine
30th Oct 2009, 01:08
TriStar is nice but way over the hill these days.

.. most of us older blokes prefer our aeroplanes to be like our women and wine .. simultaneously well aged and aged well.

You just have to cut us some slack and tolerate our reminiscing ... now, did I tell you how absolutely fantastically good the Lockheed Electra was ... ?

411A
30th Oct 2009, 06:11
....fantastically good the Lockheed Electra was ..

Was it ever! A superb airplane...of couse it was a Lockheed, so no doubt.

Spooky2, SVA is SaudiArabian, they bought 17 TriStars, all -200's.
By the way, I believe that the RAF has some of their L1011's fitted with EFIS.

Spooky 2
30th Oct 2009, 13:40
Thanks 411A. Should'a known. I to have a few hours in the L188A as both F/O and FE. It was nice and as I recall...built by Lockheed!

King on a Wing
30th Oct 2009, 16:01
411A,
Just outta curiosity.Were you ever with Saudia..?
What year(s) was that,if so.
Thanks

737forever
30th Oct 2009, 23:54
Is podstrikes a problem due to the big engines,or will the wingtip or flap faring hit first with big bank angles where the deck angle is normal? And Yes;I am talking about the 777.

Capt. Inop
31st Oct 2009, 01:45
How does the fly by wire system on the 777 work in a crosswind? Can you sideslip with cross control like a conventional aircraft or does a aileron input on the yoke just command a given roll rate.so that you have to neutrelaze the yoke once the give bank angle is achived?
And what is the normal way of doing it? I have seen both crab and wing low,but not sure what is the normal way of doing it.

Well i'm current on the B737 NG.
However i have some hours on the t7.
It behaves like any other Boeing, most of the time.
Went back to regional flights because my body watch coldn't deal with long haul flights.
Yeah it's FBW, but so what, the pilot still have control.

Capt. Inop
31st Oct 2009, 01:53
How does the fly by wire system on the 777 work in a crosswind? Can you sideslip with cross control like a conventional aircraft or does a aileron input on the yoke just command a given roll rate.so that you have to neutrelaze the yoke once the give bank angle is achived?
And what is the normal way of doing it? I have seen both crab and wing low,but not sure what is the normal way of doing it.

Well it's not an Airbus, so just like another Boeing whatever you do with the yoke and the rudder pedals the aircraft will react.

777AV8R
31st Oct 2009, 04:18
Boeing engineers designed the 777 to fly like an airplane. There is nothing magical about this aircraft. The fly-by-wire system works well, although the autopilot works better.
As for manual crosswind landings, when I teach this aircraft and those who look at the training manual, will see that a 'crab-decrab' is the best maneuver in this airplane. There is actually a note in the training manual that talk about some complications of using the sideslip method, during gusty wind conditions.

In short...this airplane is a dream to fly.

411A
31st Oct 2009, 05:42
411A,
Just outta curiosity.Were you ever with Saudia..?

Yup, for quite awhile...always on the TriStar.
Send a PM if interested.

Dopeyskydiver
17th Nov 2009, 21:43
Okay folks, since we're on this subject - can ANYONE tell me if Boeing has EVER flight tested the Backup Flight Controls in MANUAL mode? (I.E. Cable control on spoilers #4 & #11)
I am currently getting certified on the 777 and have heard from a few instructors, that boeing NEVER tested this in flight. (something about not being brave enough, blah blah, etc...):=
If anyone can help with links or any other type of info to verify or debunk this claim would be GREATLY appreciated!:D

Loose rivets
18th Nov 2009, 04:34
A bevy of brave people tried a full manual reversion landing in a new BAC1-11. It was almost catastrophic.

Both levers pulled and nearing the concrete, when it became apparent that the world was getting bigger at an inappropriate rate. PF pulled. PNF came into the loop and pulled as well. There were footrests to brace oneself against for extra pulshon.

Great result. They ended up with a dial full of blue.

Then of course the pushing contest began, but at about this time, someone with a modicum, flicked the tiny silver switch on the centre pedestal. This, if I remember correctly, gave an equivalent feel of 180kts. No doubt at that moment, there was a call to stop pushing.:}

Thems were fun days - days when pilots were issued with a lot of luck as part of their licensees.

hawk37
19th Nov 2009, 00:56
737Forever asked in the first post:

"How does the fly by wire system on the 777 work in a crosswind? Can you sideslip with cross control like a conventional aircraft or does a aileron input on the yoke just command a given roll rate.so that you have to neutrelaze the yoke once the give bank angle is achived?"

Zlin77 replied in post 2

"Flies just like a normal aircraft with crossed controls, control inputs must be maintained to displace the flight control surfaces...."

I was hoping for a clear answer (don't fly A's nor B's). Do you have to neutralize the yoke once the given bank angle is achieved, as 737forever asks?
And..when zlin77 says control inputs must be maintained to displace the flight control surfaces...is this correct? and are the ailerons in fact displaced once the desired wing down bank angle is achieved?

kijangnim
19th Nov 2009, 01:56
GREETINGS
B777 is flown like any conventional aircraft, no specials when it comes to cross-wind, cross control, side slip, whatever you feel comfortable with. :ok:
Airbus is different story (Roll Rate):}

hawk37
19th Nov 2009, 11:48
So...Kijangnim, or others...

1. Do you have to "neutralize" the yoke once bank angle is achieved in a wing down landing?

2. Will the 777 maintain the (or re acquire the same) bank angle in a gust if the ailerons are kept neutral?

3. Is it true that "control inputs must be maintained to displace the flight control surfaces" in a wing down landing?

I'm trying to use the same context (and words) of posters 1 and 2, (Zlin and 737forever) in order to understand the answers.

ratarsedagain
19th Nov 2009, 12:21
Max hand flown demonstarted xwind on the 777 is 38 kts
:confused::confused::confused:
It's 40kts for landing dry or wet on our 777's.

FullWings
19th Nov 2009, 12:22
1. Do you have to "neutralize" the yoke once bank angle is achieved in a wing down landing?
No, unless you want the wing to rise up again due to the secondary effect effect of the rudder you're using to line up with the runway.

2. Will the 777 maintain the (or re acquire the same) bank angle in a gust if the ailerons are kept neutral?
No, unless the gust takes you outside the roll envelope (c.35deg) in which case it will return to 30deg.

3. Is it true that "control inputs must be maintained to displace the flight control surfaces" in a wing down landing?
Yes, if you're doing it properly!

The aileron/flaperon displacement is proportional to control wheel deflection. There is a "gust suppression" function which can command yaw and/or roll but it's for ride comfort and is transparent to the pilot.