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Is This A "computer"or Pilot Input? Video Here...  
User currently offlinelexkid12300 From United States of America, joined Mar 2011, 89 posts, RR: 0
Posted (1 year 5 months 5 days 20 hours ago) and read 4286 times:

Hi all,

Stumbled on this video of an apparent engine failure of an A330 on takeoff, and wanted your insight on something. At 15 seconds, the right (#2) engine fails, and we see the aircraft quickly veer to the right (because at this moment only the #1 is producing thrust). Not a second later, we see an almost full deflection of the rudder, and the aircraft is quickly straightened back out.

My question: Is this quick deflection of the rudder a "pilot" input (a reaction by the crew) or is the rudder deflection controlled by the plane's computer? I only ask because the reaction is SO quick- seems almost "too" quick to be done by a human!

Here is the video:

http://www.youtube.com/watch?feature=player_embedded&v=PS1YAX70edc

Thanks for your input!

45 replies: All unread, showing first 25:
 
User currently offlinewilco737 From Greenland, joined Jun 2004, 9103 posts, RR: 76
Reply 1, posted (1 year 5 months 5 days 20 hours ago) and read 4293 times:
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Quoting lexkid12300 (Thread starter):
My question: Is this quick deflection of the rudder a "pilot" input (a reaction by the crew) or is the rudder deflection controlled by the plane's computer? I only ask because the reaction is SO quick- seems almost "too" quick to be done by a human!

This is pilot input. It looks very quick, but the reaction is very quick. Maybe they saw the engine failure a split second earlier than we saw it from the outside.

wilco737
  



It it's not Boeing, I am not going.
User currently offlinespeedbird128 From Pitcairn Islands, joined Oct 2003, 1648 posts, RR: 2
Reply 2, posted (1 year 5 months 5 days 20 hours ago) and read 4287 times:

I'd say this was pilot flying giving rudder input...

In flight with AP engaged I believe the 330 does a good job with thrust asymmetry.



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User currently onlinePihero From France, joined Jan 2005, 4638 posts, RR: 77
Reply 3, posted (1 year 5 months 5 days 16 hours ago) and read 4201 times:
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Nobody uses the autopilot for takeoff.
They correcdtly identified a compressor stall - more a surge IMO - and aborted the takeoff.

Quoting wilco737 (Reply 1):
Maybe they saw the engine failure a split second earlier than we saw it from the outside.

I think not, the rather violent yaw to the right was their clue.
Quick reaction indeed.

Then a second stall after Thrust reverser disengaged.

Correctly called for fire assistance.

Good show !



Contrail designer
User currently offlinewilco737 From Greenland, joined Jun 2004, 9103 posts, RR: 76
Reply 4, posted (1 year 5 months 5 days 16 hours ago) and read 4185 times:
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Quoting Pihero (Reply 3):
I think not, the rather violent yaw to the right was their clue.
Quick reaction indeed.

Yeah I agree. I thought maybe there was a slight indication on the N1 that could indicate that and the PF was aware that something might get wrong and then 'bang' it happened.

wilco737
  



It it's not Boeing, I am not going.
User currently offlinerfields5421 From United States of America, joined Jul 2007, 7607 posts, RR: 32
Reply 5, posted (1 year 5 months 5 days 13 hours ago) and read 4102 times:

Obviously I've never flown an A330 - but on takeoff my feet are on the rudder pedals.

Any sharp movement, winds only in my experience, and the foot automatically goes down to keep the plane pointed straight down the runway. You don't get through primary PPL training without developing that instinct.

The rudder pedal movement by the pilots very likely started before they were even aware of the bang/ sound or any instrument readings. The plane starts turning - "KEEP IT STRAIGHT"

In the A330 - the cockpit is near 80 feet in front of the main gear/ engines. The sidways movement we see on the video would be much stronger and noticable in the cockpit.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1704 posts, RR: 12
Reply 6, posted (1 year 5 months 5 days 11 hours ago) and read 4063 times:

Loss of an engine at low speed (rudder not effective) and after V1 is covered during recurrent training/check rides in the simulator continuously. The sideways movement of the nose (much more at low speed, less at high speed) is generally your first cue. The 777 has a TAC (Thrust Asymmetry Compensation System) which automatically puts in rudder both on the ground and in flight to assist the pilot with an engine failure -- similarly on the 787 -- A330 ????. Engine failures in the simulator are practiced with TAC off -- worse case scenario.

User currently offlineStarlionblue From Greenland, joined Feb 2004, 17119 posts, RR: 66
Reply 7, posted (1 year 5 months 5 days 11 hours ago) and read 4055 times:

Quoting rfields5421 (Reply 5):
Obviously I've never flown an A330 - but on takeoff my feet are on the rudder pedals.

Any sharp movement, winds only in my experience, and the foot automatically goes down to keep the plane pointed straight down the runway. You don't get through primary PPL training without developing that instinct.

The rudder pedal movement by the pilots very likely started before they were even aware of the bang/ sound or any instrument readings. The plane starts turning - "KEEP IT STRAIGHT"

Indeed. You don't even have to think about it and once the fact that something is wonky registers you're already correcting. Heck, a Cessna 172 likes to go off to either side even while working perfectly!

Quoting 7BOEING7 (Reply 6):
The 777 has a TAC (Thrust Asymmetry Compensation System) which automatically puts in rudder both on the ground and in flight to assist the pilot with an engine failure -- similarly on the 787 -- A330 ????.

A380 as well, and they actually had to introduce some "artificial" sideslip or the system does it so seamlessly that you hardly notice it if an engine goes in flight. Assuming you can't hear the alarms or see the warning lights of course.


BTW same Simon Lowe who managed to capture this. http://www.youtube.com/watch?v=9KhZwsYtNDE

[Edited 2013-06-26 09:11:40]


"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlinehivue From United States of America, joined Feb 2013, 1102 posts, RR: 0
Reply 8, posted (1 year 5 months 3 days 23 hours ago) and read 3676 times:

Quoting Pihero (Reply 3):
Then a second stall after Thrust reverser disengaged.

I think there is only one stall. It takes a while for the sound to get to where the photographer is. The slo-mo is edited to place the sound with the event.

Quoting Starlionblue (Reply 7):
BTW same Simon Lowe who managed to capture this.

You would think he would know a compressor stall by now and not title it "Jet engine explodes..."


User currently offlinemandala499 From Indonesia, joined Aug 2001, 6957 posts, RR: 76
Reply 9, posted (1 year 5 months 3 days 22 hours ago) and read 3652 times:

Quoting Starlionblue (Reply 7):
BTW same Simon Lowe who managed to capture this. http://www.youtube.com/watch?v=9KhZw...YtNDE

Is it my ears playing on me or do the 2 guys on the radio sounded the same!   
is it? Coincidence?   



When losing situational awareness, pray Cumulus Granitus isn't nearby !
User currently onlineB747400ERF From United Kingdom, joined Jun 2013, 567 posts, RR: 1
Reply 10, posted (1 year 5 months 3 days 21 hours ago) and read 3642 times:

Quoting lexkid12300 (Thread starter):
or is the rudder deflection controlled by the plane's computer?

Any computer control on the ground would be dangerous. There is no autopilot or any computer control on the ground for any commercial a/c type.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17119 posts, RR: 66
Reply 11, posted (1 year 5 months 3 days 21 hours ago) and read 3632 times:

Quoting B747400ERF (Reply 10):
There is no autopilot or any computer control on the ground for any commercial a/c type.

Except in the case of auto-rollout.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently onlinePihero From France, joined Jan 2005, 4638 posts, RR: 77
Reply 12, posted (1 year 5 months 3 days 18 hours ago) and read 3579 times:
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Quoting hivue (Reply 8):

I think there is only one stall. It takes a while for the sound to get to where the photographer is. The slo-mo is edited to place the sound with the event.

You're right.

Quoting Starlionblue (Reply 11):
Except in the case of auto-rollout.

but you still have to use / select the reverse,
unless on the 380 you progrm the brake-to-vacate feature, you wouldn't need to, generally.



Contrail designer
User currently offlinewilco737 From Greenland, joined Jun 2004, 9103 posts, RR: 76
Reply 13, posted (1 year 5 months 3 days 16 hours ago) and read 3542 times:
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HEAD MODERATOR

Quoting Pihero (Reply 12):
but you still have to use / select the reverse,
unless on the 380 you progrm the brake-to-vacate feature, you wouldn't need to, generally.

Even if you don't have the brake-to-vacate feature, you have an autobrake and this system will use the brakes to a complete stop as well. Not exactly at the taxiway you preselected, but it can brake the airplane until it stands still - without reverser.

wilco737
  



It it's not Boeing, I am not going.
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1704 posts, RR: 12
Reply 14, posted (1 year 5 months 3 days 12 hours ago) and read 3479 times:

Quoting B747400ERF (Reply 10):
Any computer control on the ground would be dangerous. There is no autopilot or any computer control on the ground for any commercial a/c type.



Except for the 777, 787 and apparently 380 ??? Automatic control of the rudder on the ground and in flight to offset asymmetric thrust.


User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3210 posts, RR: 7
Reply 15, posted (1 year 5 months 3 days 12 hours ago) and read 3468 times:

Quoting 7BOEING7 (Reply 14):
Quoting B747400ERF (Reply 10):
Any computer control on the ground would be dangerous. There is no autopilot or any computer control on the ground for any commercial a/c type.



Except for the 777, 787 and apparently 380 ??? Automatic control of the rudder on the ground and in flight to offset asymmetric thrust.

On the 777 TAC is considered a "pilot assist function" and the airplane has to be certified for V1 engine failures with it turned off. The 787 ETAC (enhanced thrust asymmetry compensation) is certified to be used for credit for a V1 engine failure. It also looks at inertial inputs in addition to thrust differences.

I don't know the A330 as well, but I'd find it really hard to believe if it didn't have some form of TAC. I'm not so sure those are manual rudder inputs. If that had been a 777 or 787, it might very well have been an automatic input.


User currently onlinePihero From France, joined Jan 2005, 4638 posts, RR: 77
Reply 16, posted (1 year 5 months 3 days 7 hours ago) and read 3378 times:
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Quoting BoeingGuy (Reply 15):
I don't know the A330 as well, but I'd find it really hard to believe if it didn't have some form of TAC

There is none on the ground, and in the air it's just the flight control normal law which computes a *sideslip target* on the PFD, indicating to the pilot the optimum rudder input to minimize spoiler deflection.
Without pilot input, the aircraft will slowly bank into the dead engine with a sideslip and a slowly diverging heading.

Quoting BoeingGuy (Reply 15):
I'm not so sure those are manual rudder inputs.

They are, as explained above.



Contrail designer
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3210 posts, RR: 7
Reply 17, posted (1 year 5 months 3 days 7 hours ago) and read 3366 times:

Quoting Pihero (Reply 16):
Quoting BoeingGuy (Reply 15):
I don't know the A330 as well, but I'd find it really hard to believe if it didn't have some form of TAC

There is none on the ground, and in the air it's just the flight control normal law which computes a *sideslip target* on the PFD, indicating to the pilot the optimum rudder input to minimize spoiler deflection.
Without pilot input, the aircraft will slowly bank into the dead engine with a sideslip and a slowly diverging heading.

Quoting BoeingGuy (Reply 15):
I'm not so sure those are manual rudder inputs.

They are, as explained above.

Well, I was surprised that the A330 wouldn't have a version of TAC like the 777 and 787 do. I thought Airbus airplanes are so much more advanced.

Quoting Pihero (Reply 12):
Quoting Starlionblue (Reply 11):
Except in the case of auto-rollout.

but you still have to use / select the reverse,
unless on the 380 you progrm the brake-to-vacate feature, you wouldn't need to, generally.

Of course, you don't have to select reverse thrust. You can rollout on autopilot, autobrakes and auto speedbrakes. Does BTV on the A380 also select reverse thrust on the inboard engines?


User currently onlineB747400ERF From United Kingdom, joined Jun 2013, 567 posts, RR: 1
Reply 18, posted (1 year 5 months 3 days 4 hours ago) and read 3313 times:

Quoting 7BOEING7 (Reply 14):
Except for the 777, 787 and apparently 380 ??? Automatic control of the rudder on the ground and in flight to offset asymmetric thrust.

That isn't an autopilot or automatic control, that's assisting the pilot who is controlling. That is just a feature of fly by wire. The pilot is still in command.


User currently offlineStarlionblue From Greenland, joined Feb 2004, 17119 posts, RR: 66
Reply 19, posted (1 year 5 months 3 days 3 hours ago) and read 3284 times:

Quoting BoeingGuy (Reply 17):
Well, I was surprised that the A330 wouldn't have a version of TAC like the 777 and 787 do. I thought Airbus airplanes are so much more advanced.

They aren't really. They're just more blatant in how the technology is used.



"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1704 posts, RR: 12
Reply 20, posted (1 year 5 months 3 days 2 hours ago) and read 3262 times:

Quoting B747400ERF (Reply 18):
That isn't an autopilot or automatic control, that's assisting the pilot who is controlling. That is just a feature of fly by wire. The pilot is still in command.

I would hope that the pilot is still in command of the autopilot. As pointed out above, in the 787 the pilot doesn't have to touch the rudders -- in my book that's an automatic control.


User currently onlinePihero From France, joined Jan 2005, 4638 posts, RR: 77
Reply 21, posted (1 year 5 months 3 days 2 hours ago) and read 3259 times:
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Quoting BoeingGuy (Reply 17):
Well, I was surprised that the A330 wouldn't have a version of TAC like the 777 and 787 do. I thought Airbus airplanes are so much more advanced.

Study the différences on flight control philosophies. The reason is obvious, it's been there since the A320 and nothing has been added as nothing was needed. Even the A380 doesn't have it : same reason : not needed.
Your argument is highly amusing. When A does automated, it's taking pilot's job. When B does, it's *Advanced*.
Ridiculous.

Quoting B747400ERF (Reply 18):
That isn't an autopilot or automatic control, that's assisting the pilot who is controlling.

False.

Quoting B747400ERF (Reply 18):
That is just a feature of fly by wire.

False, at least not for all.

Quoting B747400ERF (Reply 18):
The pilot is still in command.

Apparently, less than on an Airbus, which is - again - quite amusing.

[Edited 2013-06-28 18:10:53]


Contrail designer
User currently onlinePihero From France, joined Jan 2005, 4638 posts, RR: 77
Reply 22, posted (1 year 5 months 3 days 2 hours ago) and read 3256 times:
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Quoting BoeingGuy (Reply 17):
Of course, you don't have to select reverse thrust. You can rollout on autopilot, autobrakes and auto speedbrakes.

...and do you know where you'd stop without the BTV ?
Oh! I know : *not invented here*, right ?



Contrail designer
User currently offlinezeke From Hong Kong, joined Dec 2006, 9210 posts, RR: 76
Reply 23, posted (1 year 5 months 2 days 19 hours ago) and read 3161 times:

Quoting lexkid12300 (Thread starter):
My question: Is this quick deflection of the rudder a "pilot" input (a reaction by the crew) or is the rudder deflection controlled by the plane's computer? I only ask because the reaction is SO quick- seems almost "too" quick to be done by a human!

Pilot input to the change of heading initially, then you see the decision to reject the takeoff with the reverse being selected. The rudder inputs are being used to tack along the runway centre line, you can see this change as the engine is brought into reverse.

Quoting BoeingGuy (Reply 15):
On the 777 TAC is considered a "pilot assist function" and the airplane has to be certified for V1 engine failures with it turned off. The 787 ETAC (enhanced thrust asymmetry compensation) is certified to be used for credit for a V1 engine failure. It also looks at inertial inputs in addition to thrust differences.

I think you are a little confused as to what TAC can and cannot do. TAC works by looking at the thrust difference between the engines, it needs around 6k of thrust difference and for the aircraft to be above 70 kts for TAC to start working . TAC stops working as soon as reverse is applied, and may activate if the engine thinks there is a thrust difference when there is none, and may turn itself off if there is an engine failure (engine computers have bad data). It is not fool proof. TAC inputs are added regardless if the pilot has added rudder trim as well.

TAC works by adding rudder trim control, which then moves the pedals, which then moves the rudder, except on takeoff. On takeoff TAC adds a boot full of rudder directly which is not fed back to the pilots flight controls, at the same time TAC adds a high rate rudder trim control, which then moves the pedals, they later catch up with the actual rudder position (so for a while the actual TAC inputs are not available to the pilots).

The system in the Airbus FBW is not fool proof either it also relies on engine parameters, however it also uses the flight control system to see if there is actually any yaw. The roll and rudder commands supplied to the FBW system are not available to teh pilots either on the Airbus, they are added like any other turn co-ordination or yaw damping would be added, i.e. automatically.

Quoting BoeingGuy (Reply 17):
Well, I was surprised that the A330 wouldn't have a version of TAC like the 777 and 787 do. I thought Airbus airplanes are so much more advanced.

On the ground the A330 is in a direct law, where the pilot inputs are a direct relationship with the control surfaces, as they transition to flight mode, the normal law is blended in. If the pilot continued the takeoff, and only applied back stick to rotate, the aircraft will be laterally stable with the normal law containing the engine failure with roll and rudder inputs. The pilot is then presented with indication as to what rudder input is required to achieve best performance, and they can use either/or the rudder pedals, or the rudder trim, or the autopilot to achieve this.

A pilot *could* just rotate, get airborne, press the autopilot, and let the aircraft trim itself out without any rudder input whilst airborne and remain laterally stable. As Pherio said "Without pilot input, the aircraft will slowly bank into the dead engine with a sideslip and a slowly diverging heading.", press the autopilot, and it is all corrected.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlineStarlionblue From Greenland, joined Feb 2004, 17119 posts, RR: 66
Reply 24, posted (1 year 5 months 2 days 17 hours ago) and read 3123 times:

Incidentally, certification requires no more than 30 feet deviation from centerline for an engine failure at the worst possible time (Vef) with the other engine at take-off thrust without using nosewheel steering; just rudder. This indicates that while reaction time must be quick, keeping it near centerline is not a huge issue. As mentioned before, any change in the sight picture will more or less subconsciously lead to a pedal deflection, and this starts at the private pilot level.

[Edited 2013-06-29 03:23:36]


"There are no stupid questions, but there are a lot of inquisitive idiots."
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3210 posts, RR: 7
Reply 25, posted (1 year 5 months 2 days 8 hours ago) and read 3063 times:

Quoting zeke (Reply 23):
Quoting BoeingGuy (Reply 15):
On the 777 TAC is considered a "pilot assist function" and the airplane has to be certified for V1 engine failures with it turned off. The 787 ETAC (enhanced thrust asymmetry compensation) is certified to be used for credit for a V1 engine failure. It also looks at inertial inputs in addition to thrust differences.

I think you are a little confused as to what TAC can and cannot do. TAC works by looking at the thrust difference between the engines, it needs around 6k of thrust difference and for the aircraft to be above 70 kts for TAC to start working . TAC stops working as soon as reverse is applied, and may activate if the engine thinks there is a thrust difference when there is none, and may turn itself off if there is an engine failure (engine computers have bad data). It is not fool proof. TAC inputs are added regardless if the pilot has added rudder trim as well.

TAC works by adding rudder trim control, which then moves the pedals, which then moves the rudder, except on takeoff. On takeoff TAC adds a boot full of rudder directly which is not fed back to the pilots flight controls, at the same time TAC adds a high rate rudder trim control, which then moves the pedals, they later catch up with the actual rudder position (so for a while the actual TAC inputs are not available to the pilots).

I am fully aware of what TAC does. I'm not sure what in my comment made you think otherwise. The 777 uses engine thrust differntial. 787 ETAC also uses inertial inputs, and the latter is allowed use as the part of the certification for engine failure at V1 on the 787.


User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3210 posts, RR: 7
Reply 26, posted (1 year 5 months 2 days 8 hours ago) and read 3054 times:

Quoting Pihero (Reply 21):
Quoting B747400ERF (Reply 18):
The pilot is still in command.

Apparently, less than on an Airbus, which is - again - quite amusing.

Actually the pilot is in full command. TAC assists the pilot. They can override with a manual rudder input or turn it off if they so choose. All 777 and 787 envelope protection functions can be over-riden by the pilot. That is not true on Airbus.

Quoting Pihero (Reply 21):
Quoting B747400ERF (Reply 18):
That is just a feature of fly by wire.

False, at least not for all.

Only the 777 and 787 have it, so it is in effect a feature of fly by wire. The original comment was correct for Boeing at least.

Quoting Starlionblue (Reply 19):
Quoting BoeingGuy (Reply 17):
Well, I was surprised that the A330 wouldn't have a version of TAC like the 777 and 787 do. I thought Airbus airplanes are so much more advanced.

They aren't really. They're just more blatant in how the technology is used.

I was being sarcastic since everyone seem think they are.


User currently onlinePihero From France, joined Jan 2005, 4638 posts, RR: 77
Reply 27, posted (1 year 5 months 2 days 3 hours ago) and read 3010 times:
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Quoting BoeingGuy (Reply 17):
Well, I was surprised that the A330 wouldn't have a version of TAC like the 777 and 787 do. I thought Airbus airplanes are so much more advanced.
Quote:
quote=BoeingGuy,reply=26]everyone seem think they are.

So, what is more Advanced ? A design that precedes the 777 by some seven years and has basically not added anything to the general architecture of the flight controls system (no tail scrape protection, no TAC, no windshear special addendums...) or a design that gets more and more new additions, some quite different from the "777 and 787 envelope protection functions can be over-riden by the pilot".
Have a look at the 787 windshear / stall protection to see what mean.

Quoting BoeingGuy (Reply 26):
Actually the pilot is in full command. TAC assists the pilot. They can override with a manual rudder input or turn it off if they so choose.

According to Zeke's description, with which I concur, your statement is a prime example of fanboy's disingenuity :
"...On takeoff TAC adds a boot full of rudder directly which is not fed back to the pilots flight controls, at the same time TAC adds a high rate rudder trim control, which then moves the pedals, they later catch up with the actual rudder position (so for a while the actual TAC inputs are not available to the pilots)..."



Contrail designer
User currently offlinezeke From Hong Kong, joined Dec 2006, 9210 posts, RR: 76
Reply 28, posted (1 year 5 months 2 days 2 hours ago) and read 2996 times:

Quoting BoeingGuy (Reply 26):

Just to be clear, are you saying on the 777/787 the pilot needs to make no rudder inputs at all in the event of an engine failure ?

Are you saying that the TAC inputs are directly and immediately feedback to the cockpit flight controls ?

Are you saying that when a pilot adds rudder trim in when TAC is active they over ride the TAC inputs ?

Are you saying the pilots can always override the aircraft without the need to turn anything off ?

My understanding is all of the above are false, the sort of details that are lost in the truth.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3210 posts, RR: 7
Reply 29, posted (1 year 5 months 1 day 23 hours ago) and read 2964 times:

Quoting Pihero (Reply 27):
Have a look at the 787 windshear / stall protection to see what mean.

First of all, no Boeing airplane has an automatic windshear mode. The TO/GA mode is programed for windshear protection when the crew pushes the TO/GA switch. The 787 and all Boeing airplanes have both Predictive Windshear and Reactive Windshear alerting.

The stall protection gives a down elevator command and increases backdrive force on the column. If the pilot pulls back on the column, that input is summed with the nose down elevator command.

Quoting Pihero (Reply 27):
According to Zeke's description, with which I concur, your statement is a prime example of fanboy's disingenuity :

I guess I didn't realize that you guys were such experts on the engineering details of Boeing airplanes. I've only been involved with them for 25 years.


User currently onlinePihero From France, joined Jan 2005, 4638 posts, RR: 77
Reply 30, posted (1 year 5 months 1 day 16 hours ago) and read 2873 times:
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Quoting BoeingGuy (Reply 29):
I guess I didn't realize that you guys were such experts on the engineering details of Boeing airplanes. I've only been involved with them for 25 years.

...and kept blind on oither's réalisations... Braaaaavo !

Quoting BoeingGuy (Reply 29):
First of all, no Boeing airplane has an automatic windshear mode.

Who said anything about it ? even on a 'Bus ?

Quoting BoeingGuy (Reply 29):
The stall protection gives a down elevator command and increases backdrive force on the column. If the pilot pulls back on the column, that input is summed with the nose down elevator command.

... and I hope that's not what B pilots are taught.
Secondly, tell us détails about the 787 protection, which is quite different from the 777and closer to what Airbus has done for nearly thirty years.
"Advanced", you said ?



Contrail designer
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1704 posts, RR: 12
Reply 31, posted (1 year 5 months 1 day 10 hours ago) and read 2799 times:

Quoting zeke (Reply 28):
Just to be clear, are you saying on the 777/787 the pilot needs to make no rudder inputs at all in the event of an engine failure ?

FALSE--For the 777 it assists the pilot but the pilot will need to make rudder inputs. Engine failures during recurrent/checkrides in the simulator are conducted with TAC selected off because not all types of engine failures will trigger TAC.

Quoting zeke (Reply 28):
Are you saying that the TAC inputs are directly and immediately feedback to the cockpit flight controls ?

TRUE

Quoting zeke (Reply 28):
Are you saying that when a pilot adds rudder trim in when TAC is active they over ride the TAC inputs ?

TRUE

Quoting zeke (Reply 28):
Are you saying the pilots can always override the aircraft without the need to turn anything off ?

TRUE

Quoting zeke (Reply 28):
My understanding is all of the above are false, the sort of details that are lost in the truth.

FALSE


User currently offlineBoeingGuy From United States of America, joined Dec 2010, 3210 posts, RR: 7
Reply 32, posted (1 year 5 months 1 day 4 hours ago) and read 2707 times:

Quoting Pihero (Reply 30):
Quoting BoeingGuy (Reply 29):
I guess I didn't realize that you guys were such experts on the engineering details of Boeing airplanes. I've only been involved with them for 25 years.

...and kept blind on oither's réalisations... Braaaaavo !

And you're an expert on Boeing airplanes, how?

Quoting Pihero (Reply 30):
Quoting BoeingGuy (Reply 29):
First of all, no Boeing airplane has an automatic windshear mode.

Who said anything about it ? even on a 'Bus ?
Quoting Pihero (Reply 27):
Have a look at the 787 windshear / stall protection to see what mean.


User currently offlinezeke From Hong Kong, joined Dec 2006, 9210 posts, RR: 76
Reply 33, posted (1 year 5 months 1 day 2 hours ago) and read 2671 times:

Quoting 7BOEING7 (Reply 31):

I do not really see that big of a difference between what we see on the A330 in the OP, and what you are talking about with the 777, common problem, different solutions. Neither is perfect, and given your response, not that well understood even by people claiming to work for the manufacturer. I am not really seeing anything someone can call more advanced.

The A330 FBW, and TAC both need a pilot to apply some rudder to achieve best performance, however not using rudder will result in slightly less than best performance with a diverging heading, however not dangerous. I am reluctant to post direct details from Boeing manuals as there is a history of people then using SD to delete my posts when they do not like what they see.

A non proprietary version of the information is available on this 777 check captains website http://www.flight.org/blog/2011/05/10/thrust-asymmetry-compensation/



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1704 posts, RR: 12
Reply 34, posted (1 year 5 months 1 day ago) and read 2636 times:

Quoting zeke (Reply 33):
The A330 FBW, and TAC both need a pilot to apply some rudder to achieve best performance, however not using rudder will result in slightly less than best performance with a diverging heading, however not dangerous.

Only during takeoff. In cruise at normal airspeed the TAC generally has enough authority to maintain heading on its own and the people in back, the very back may not even notice the yaw during a gradual engine spool down.


User currently onlineB747400ERF From United Kingdom, joined Jun 2013, 567 posts, RR: 1
Reply 35, posted (1 year 5 months 23 hours ago) and read 2632 times:

Quoting Pihero (Reply 21):
Apparently, less than on an Airbus, which is - again - quite amusing.
Quoting 7BOEING7 (Reply 20):
I would hope that the pilot is still in command of the autopilot. As pointed out above, in the 787 the pilot doesn't have to touch the rudders -- in my book that's an automatic control.

Well the 787 is a new type that I am not familiar with, and the topic here was the A330 in the first place. So I'm not really sure the point of this argument by either of you.


User currently offline7BOEING7 From United States of America, joined Oct 2012, 1704 posts, RR: 12
Reply 36, posted (1 year 5 months 23 hours ago) and read 2632 times:

Quoting B747400ERF (Reply 35):
Well the 787 is a new type that I am not familiar with, and the topic here was the A330 in the first place. So I'm not really sure the point of this argument by either of you.



It got hijacked when you said "computer control on the ground was dangerous" and has been a discussion of that ever since.


User currently offlinezeke From Hong Kong, joined Dec 2006, 9210 posts, RR: 76
Reply 37, posted (1 year 5 months 23 hours ago) and read 2633 times:

Quoting 7BOEING7 (Reply 34):
Only during takeoff. In cruise at normal airspeed the TAC generally has enough authority to maintain heading on its own and the people in back, the very back may not even notice the yaw during a gradual engine spool down.

In normal operations (i.e. with the autopilot on), neither the A330 or 777 will not have a heading change as a result of an engine spool down. Passengers would not feel anything except for the commencement of a descent to a single engine level.

Quoting B747400ERF (Reply 35):
Well the 787 is a new type that I am not familiar with, and the topic here was the A330 in the first place.

There is some incorrect information seems to have been being presented here, Boeing's 787 FCTM does say some rudder is required by the pilot. Reference document is the 787 FCTM 3.30 "Engine Failure Recognition". Claims made in reply 31 are also incorrect, a public reference is provided in reply 33.

I have tried to provide a balanced and informed discussion with a comparison to the A330 in the OP.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1704 posts, RR: 12
Reply 38, posted (1 year 5 months 22 hours ago) and read 2611 times:

Quoting zeke (Reply 37):
Claims made in reply 31 are also incorrect, a public reference is provided in reply 33.

Could you be specific please.


User currently offlinezeke From Hong Kong, joined Dec 2006, 9210 posts, RR: 76
Reply 39, posted (1 year 5 months 20 hours ago) and read 2592 times:

Quoting lexkid12300 (Thread starter):
Here is the video:

http://www.youtube.com/watch?feature...70edc

I found another view of the same incident on youtube, this video is by Eddie Leathwood

http://www.youtube.com/watch?v=XRL8MPnXmFw

The video gives a different angle to the engine event, and another viewpoint to see the rudder inputs. The change in aircraft heading also seems more noticeable than the head on video, maybe due to it being shot closer.

Apparently the registration was G-OMYT operating MT-314, I am yet to see anything on the AAIB site.

Quoting 7BOEING7 (Reply 38):
Could you be specific please.

I do not plan on doing a copy and paste of the whole page, the page is well written, and easy to follow. A fair use excerpt from http://www.flight.org/blog/2011/05/10/thrust-asymmetry-compensation/

"In response to a sudden loss of thrust during takeoff, TAC commands a high rate rudder input direct to the flight control surfaces – this rudder deflection is not fed back through to the rudder pedals. At the same time the TAC commands a high rate rudder trim input (remember there are two rates of trim input on the 777 – half twist is half rate trim, full twist is full rate trim command) which moves the rudder pedals until the amount of rudder commanded by the rudder pedals (as felt by the pilot) is the same as is being commanded by the TAC direct to the rudders as a result of the thrust discrepancy."

where you indicated TRUE to "TAC inputs are directly and immediately feedback to the cockpit flight controls" when it is not the case. There is a lag due to the rudder trim control being used to move the rudder pedals.This is one of the reasons why some pilots have a small PIO on takeoff in the 777 simulator following an engine failure.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1704 posts, RR: 12
Reply 40, posted (1 year 5 months 8 hours ago) and read 2411 times:

Quoting zeke (Reply 39):
where you indicated TRUE to "TAC inputs are directly and immediately feedback to the cockpit flight controls" when it is not the case. There is a lag due to the rudder trim control being used to move the rudder pedals

Ok, so I missed the "lag" which isn't even noticeable when you pull and engine back. Do you agree the other three statements in Reply 31 are TRUE and not FALSE as you indicated?


User currently onlinePihero From France, joined Jan 2005, 4638 posts, RR: 77
Reply 41, posted (1 year 5 months 4 hours ago) and read 2360 times:
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Quoting 7BOEING7 (Reply 31):
Quoting zeke (Reply 28):Are you saying that the TAC inputs are directly and immediately feedback to the cockpit flight controls ?
TRUE

A bit too fast an answer, wasn't it ?.. Some *lag* indeed !

Quoting 7BOEING7 (Reply 31):
Quoting zeke (Reply 28):Are you saying that when a pilot adds rudder trim in when TAC is active they over ride the TAC inputs ?
TRUE

Does he really need to, as the FCOM says :

"If an engine fails after liftoff, the TAC automatically inputs rudder to fully compensate for the yaw resulting from asymmetrical thrust.....

....After several seconds, TAC applies sufficient rudder to make it possible for the pilot or autopilot to center the control wheel. The amount of rudder used is proportional to the engine thrust difference....
"

Seems to me a lot more than "a "pilot assist function" ( your own words )

You may notice that I grant you the *pilot overriding possibility* bit... In this case, why have such a device ?

Quoting BoeingGuy (Reply 32):
And you're an expert on Boeing airplanes, how?

Guess how ...  



Contrail designer
User currently onlinePihero From France, joined Jan 2005, 4638 posts, RR: 77
Reply 42, posted (1 year 5 months 4 hours ago) and read 2360 times:
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Quoting BoeingGuy (Reply 15):
If that had been a 777 or 787, it might very well have been an automatic input.

FALSE
The FCOM again :
"if the engine is damaged or surges, TAC disengages because there is no accurate prediction of engine thrust".

This video shows an engine surge. So even on a 777, it would have been pilot rudder input to keep the plane on the runway.
QED



Contrail designer
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1704 posts, RR: 12
Reply 43, posted (1 year 5 months 3 hours ago) and read 2335 times:

Quoting Pihero (Reply 41):
"If an engine fails after liftoff, the TAC automatically inputs rudder to fully compensate for the yaw resulting from asymmetrical thrust.....

....After several seconds, TAC applies sufficient rudder to make it possible for the pilot or autopilot to center the control wheel. The amount of rudder used is proportional to the engine thrust difference...."

Seems to me a lot more than "a "pilot assist function" ( your own words )

What would you call it then?? During takeoff if the pilot senses a yaw he needs to put in rudder, he doesn't sit there and wait to see if the TAC is doing it for him. If he waited and TAC wasn't working he'd be off the runway in a hurry. Again, in the simulator, during initial training I may have seen a engine out takeoff with TAC functioning but after that all engine out takeoffs were with TAC inop. It's a "first" generation system as opposed to a "second" generation system on the 787.

If the engine fails sometime after takeoff and it's not a big bang to wake you up, its there to protect you if you're not paying attention -- "first" generation system. China Airlines flight 006.

No need to make this an A vs B issue -- most of this discussion was to counter the "computer control on the ground was dangerous" comment.


User currently onlinePihero From France, joined Jan 2005, 4638 posts, RR: 77
Reply 44, posted (1 year 5 months 2 hours ago) and read 2327 times:
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Stupid question :
Where does the book mention a pilot intervention before *centering* the control wheel ??

Quoting 7BOEING7 (Reply 43):
No need to make this an A vs B issue

For me it hasn't been one. Ask elsewhere.



Contrail designer
User currently offline7BOEING7 From United States of America, joined Oct 2012, 1704 posts, RR: 12
Reply 45, posted (1 year 5 months 1 hour ago) and read 2310 times:

Quoting Pihero (Reply 44):
Stupid question :
Where does the book mention a pilot intervention before *centering* the control wheel ??

If you're talking about the China 006 comment, that was a reference to pilots "falling a sleep" at the wheel with an engine failure that doesn't scream out "I'm failing". Had they had a system similar to TAC things may have been different.


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