gospelle
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Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 12:10 am

Air Canada flight 190 on Thursday had a dramatic incident mid flight which sent several people to hospital and required an emergency landing in Calgary. At first glance it sounds like a severe turbulance incident, but as interviews with the passengers came in, the more this looks like something more puzzling.

First of all, when the plane was brought under control, the pilot announced to the passengers that "the autopilot had malfunctioned and that they had to take control of the plane manually". The pilot also announced that a computer was "knocked out" and that they weren't sure if it was knocked out before or after the incident.

From various interviews seen on local tv (I live in Calgary) and on the net, it appears during level flight at 35,000 ft. the plane suddenly and dramatically tilted to the left, bringing the wings near perpendicular to the ground and dropped fast enough to send passengers and items up to the ceiling. Many passengers said it felt as though the plane was about to "flip" over. Then the plane tilted to the right and then back to left at least 3 times. This kept up for about 10-15 seconds.

Total altitude lost during incident was about 4000 ft.

Eye witness accounts said that even buckled passengers were slammed into the side of the plane or armrests. In one case a passenger said she saw people hanging onto their armests to hold themselves in their seat and the armrests bent about 30 degres from the strain.

Clearly Air Canada, TSB and NTSB will investigate and until then we'll likely not know the exact cause, but I was hoping some of the pilots and airline techs on the forum might like to speculate what would cause such a failure.

The sudden tilt of the plane and loss of control sound similar to the freak rudder hydraulic issue that crashed some 737's and nearly crashed another. (UA 595 March 1991, USAir 427 Sept. 1994 for example). In one of the 737 cases where the plane recovered and landed, there is mention of the autopilot as well (Continental April 11, 1994 in Honduras). I wonder if this issue with Air Canada is a similar issue.

Your thoughts?
 
mark5388916
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 12:14 am

Well that would be really bad! I presume they can look back at the CVR to see what the piltos said when it happend. Also can you tell by looking at the auto pilot when it broke?

Mark
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VC-10
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 12:18 am

What is the point of speculating? A complete waste of time when the facts are unknown, any professional worth his/her salt would not guess at the cause. Especially if the only eyewitnesses are passengers when it has been proved in the past they are prone to exaggeration
 
avioniker
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 12:19 am

The DFDR will have the flight control inputs and movements recorded along with the attitude and Nav inputs of the aircraft at the time of the incident. They've come a long way from the 6 parameter days with foil tape.
If it was a flight control malfunction it'll be fairly obvious if the ailerons and rudder displaced abruptly with the plane in straight and level flight and no commanded inputs.

 Smile
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
miles_mechanic
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 12:24 am

Hi everyone. I know that Turbulence has been bad the past while between Calgary and Vancouver, I flew out to Vancouver and back on Tuesday before this flight, and we had some pretty good turbulence that was tossing our E190 around. Also the barometric pressure was lower then I have ever seen it, on the monday the ATIS was saying that the baro was 28.91. the controllers were making special care to make sure the pilots knew it was 28 and not 29. so with such low pressure, it allows intense weather conditions to exist. So this is my take on things from Calgary. It could possibly be a mechanical failure, but I know the weather conditions are unusual for sure.

Regards

Miles.
 
tdscanuck
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 1:16 am



Quoting Gospelle (Thread starter):

Total altitude lost during incident was about 4000 ft.

Air Canada originally said 65'. Where did the 4000 figure come from? Passengers tend to *vastly* overestimate the true magnitude of altitude changes. 4000 feet for this event would be a 16000-24000 ft/minute descent.

Quoting Gospelle (Thread starter):
Eye witness accounts said that even buckled passengers were slammed into the side of the plane or armrests. In one case a passenger said she saw people hanging onto their armests to hold themselves in their seat and the armrests bent about 30 degres from the strain.

Armrests are hinged upward...how you use them to hold yourself down?

Quoting Gospelle (Thread starter):
The sudden tilt of the plane and loss of control sound similar to the freak rudder hydraulic issue that crashed some 737's and nearly crashed another.

Except a rudder hardover doesn't oscillate, it goes one way and stays there. That's the opposite of what happened here.

Quoting Gospelle (Thread starter):
In one of the 737 cases where the plane recovered and landed, there is mention of the autopilot as well (Continental April 11, 1994 in Honduras). I wonder if this issue with Air Canada is a similar issue.

The autopilots are very different. Although the symptoms could be the same, I'm not sure the underlying causes could be.

Tom.
 
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zeke
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 11:52 am



Quoting Tdscanuck (Reply 5):

Air Canada originally said 65'. Where did the 4000 figure come from? Passengers tend to *vastly* overestimate the true magnitude of altitude changes. 4000 feet for this event would be a 16000-24000 ft/minute descent.

TC are saying bank angle to the right was 35 degrees, left 50 degrees, and altitude change of 900' which disconnected the autopilot, likely severe turbulence occurrence caused by an atmospheric bore.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
Gofly
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 12:13 pm



Quoting VC-10 (Reply 2):
What is the point of speculating? A complete waste of time when the facts are unknown, any professional worth his/her salt would not guess at the cause. Especially if the only eyewitnesses are passengers when it has been proved in the past they are prone to exaggeration

Exactly.

The only factual report I could come across was this one:

Occurrence Type: Accident
Occurrence Date: 2008/01/10
Occurrence Time: 1500 Z
Day Or Night: day-time
Fatalities: 0 Injuries: 6

Canadian Aerodrome ID: CYYC Aerodrome Name: Calgary Intl
Occurrence Location: Vicinity Calgary Intl (CYYC) Province: Alberta
Country: CANADA World Area: North America

Reported By: NAV CANADA AOR Number: 89221-V1

Flight #: ACA 190
Aircraft Category: Aeroplane Country of Registration: CANADA
Make: AIRBUS Model: A319 114
Year Built: 1998
Amateur Built: No
Engine Make: CFM INTERNATIONAL
Engine Model: CFM56-5A5
Engine Type: Turbo fan
Gear Type: Land
Phase of Flight: Cruise
Damage: No Damage
Owner: AIR CANADA
Operator: AIR CANADA (5262)
Operator Type: Commercial

ACA 190, an A319 with 88 people on board, was en route from Victoria to Toronto when the crew advised ATC of an aircraft upset that resulted in the aircraft doing a roll. The flight was in the vicinity of ONSET intersection (Washington state) about 65 NM southwest of Cranbrook when the crew informed Seattle Center that they were having difficulty controlling the aircraft. It is not known at this point if there was a flight management system problem or whether this event was related to turbulence. Vancouver ACC accepted control of the aircraft at 1450z. The crew declared an emergency, requested diversion to Calgary International Airport and requested medical assistance upon arrival. ACA 190 landed about 30 minutes later at 1529z and stopped on Runway 34 for visual inspection of the aircraft by airport emergency response personnel. The crew then taxied off the runway at 1533z. It was reported that there are some passengers with serious injuries. Medical assistance was on standby upon arrival. TSB Edmonton has sent two investigators to YYC.


-Gofly
Living the high life on my ex-Airliners.net Moderator pension...
 
gospelle
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 7:43 pm



Quoting VC-10 (Reply 2):
What is the point of speculating? A complete waste of time when the facts are unknown, any professional worth his/her salt would not guess at the cause. Especially if the only eyewitnesses are passengers when it has been proved in the past they are prone to exaggeration

I am not a professional, so I have no "salt". I WANT to speculate. That's the whole point of my thread. Of course passengers exagerate, but based on several reports, a "theme" can be seen. one of which is that the plane had a severe and sustained "roll". that is obviously NOT turbulence. So if we all concede that, then let's speculate a bit. What WOULD cause a severe and sustained roll?

Quoting Tdscanuck (Reply 5):
Air Canada originally said 65'. Where did the 4000 figure come from?

As I said in my OP, I gathered my data from local news reports and the internet. For this specific number I used a report from CTV: http://www.ctv.ca/servlet/ArticleNew...ce_080111/20080111?hub=CTVNewsAt11

Quoting Tdscanuck (Reply 5):
Armrests are hinged upward...how you use them to hold yourself down?

The plane had rolled. So the armrests were being bent SIDEWAYS. For example Just imagine being buckled into a seat that is suddenly tipped onto it's side. You would be hanging onto the armrest to hold yourself UP, not down. BTW, this account was from a CNN news interview with a passenger on TV so I do not have a link for it.

Quoting Tdscanuck (Reply 5):
Except a rudder hardover doesn't oscillate, it goes one way and stays there. That's the opposite of what happened here.

Fair point. So what would cause this?
 
gospelle
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 8:03 pm



Quoting Tdscanuck (Reply 5):
Except a rudder hardover doesn't oscillate, it goes one way and stays there. That's the opposite of what happened here.

I've had a few minutes to research this since my last post and while you're correct that it doesn't oscillate, there are confirmed reports from 737 events of the locked PCU "letting go" followed shortly after by another lock up. Of course in the case of the 737's, the pilots would have been standing on the opposite rudder so that when it "let go" the plane would temporarily roll the other way. A further "lock up" event immediately after would certainly cause the effect to resemble occilation. Besides, the main "theme" of the passenger accounts in this case seem to be of the plane recurring to flip "left", not "occilation".

In a fly by wire A319 would the pilots be "fighting" with controls which would cause a sudden opposite roll if a locked PCU "let go"? I personally have no idea? Any airbus pilots here know?
 
SPREE34
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 8:29 pm



Quoting Gospelle (Reply 8):
a severe and sustained "roll". that is obviously NOT turbulence.

Obviously not turbulence? What makes it obviously not turbulence? What constitutes severe and sustained?
I don't understand everything I don't know about this.
 
greasespot
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 8:43 pm



Quoting VC-10 (Reply 2):
What is the point of speculating?

Speculating gives people something to talk about. Are we supposed to just ignore a major event until the report comes out in a few years... I am/was a professional and we did it all the time at work...It is part of the human condition..It is called curiosity.

GS
Sometimes all you can do is look them in the eye and ask " how much did your mom drink when she was pregnant with you?"
 
KensukeAida
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 8:53 pm

Quoting Gospelle (Thread starter):
From various interviews seen on local tv (I live in Calgary) and on the net, it appears during level flight at 35,000 ft. the plane suddenly and dramatically tilted to the left, bringing the wings near perpendicular to the ground and dropped fast enough to send passengers and items up to the ceiling. Many passengers said it felt as though the plane was about to "flip" over. Then the plane tilted to the right and then back to left at least 3 times. This kept up for about 10-15 seconds.

It *should* be impossible to do this in controlled flight on an A319 (maximum 33 degree bank angle). Either it was a really bad computer failure (not just the autopilot), or it was *very* severe turbulence. A rudder handover seems less likely given the behavior exhibited.

- John

[Edited 2008-01-13 12:54:20]
 
gospelle
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 8:55 pm



Quoting SPREE34 (Reply 10):
Obviously not turbulence? What makes it obviously not turbulence?

I guess I'm relying on my own turbulence experience (lots) and the fact that the pilot came on the intercom afterwards and said they had an autopilot malfunction, computer out and had to fly manually. If there are any pilots reading who can tell me if a purely air effect could cause 3 repeated "Left" rolls of 50 degrees, kill a computer and autopilot, then I'll stand corrected.
 
avioniker
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 9:25 pm

Okay so now we're speculating

The SEC could easily cause a problem like this as could the ELAC. Either unit having a major internal fault will render the Autopilots inoperative.

Considering the reported 30+ degree rolls I'd hesitate to look at the rudder channels as a "starter" of the problem but they could easily contribute.

We're talking about a fully integrated flight control system on this aircraft. The autopilot is a subfunction of the flight control system rather than a fully independant box installed separately like the DC-10 or Classic Boeings.
The sidestick inputs are sent to the F/CTL computers that then cause the appropriate flight control movements. In autopilot operation the inputs are to the F/CTL computers from the FMS or whatever is coupled for navigation and steering and they're handled very much the same as the sidestick inputs.

When an upset is experienced, logic dictates that the aircrew not use any system that might possibly cause the upset to repeat. Thus, no autopilot until it can be tested and determined safe for continued service or repaired as appropriate. That's done on the ground by licensed mechanics where it's safe.

In the 90's there were a number of 320 uncommanded roll problems, some more severe than others, which resulted in more than one service bulletin on the Flight Control Computers and ELAC's.
Speculate all you want but once the FDR and FCC components are put across a bench with a good tech, I have every confidence that the story will come out.

Now as to my "two cents worth" on the armrests; They're part of the 9G restraint system requirement of, in the US, FAR part 21/25. I find it highly difficult to believe that a passenger's body or any part of a body bent one laterally without major injury.

 Smile
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
Pihero
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 9:29 pm



Quoting Gospelle (Reply 13):
I guess I'm relying on my own turbulence experience (lots)

Where ? as what ? on what ?

Quoting Gospelle (Reply 13):
and the fact that the pilot came on the intercom afterwards and said they had an autopilot malfunction, computer out and had to fly manually.

I also read that the pilot said that the A/P was "knocked out" and that they had "to fly manually"

Quoting Gospelle (Reply 13):
If there are any pilots reading who can tell me if a purely air effect could cause 3 repeated "Left" rolls of 50 degrees, kill a computer and autopilot, then I'll stand corrected.

The poor souls who went into a roll behind a big jet and crashed could have told you that *purely air effects* can do that, too.
From the 320 family AOM :
..." In normal law, with all protections available, the A/P will disengage if

  • High speed protection is active
  • AoA protection is active ( alpha prot + 1° is reached )
  • Pitch attitude exceeds 25° up or 13° down
  • Bank angle exceeds 45°...


Could that explain the wording of a *knocked-out* A/P ?
I wonder....  Confused
Contrail designer
 
gospelle
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 11:15 pm

Quoting Pihero (Reply 15):
Bank angle exceeds 45°...

Could that explain the wording of a *knocked-out* A/P ?

If the reports of 50 degree bank is correct then I guess it could explain the A/P "knocking out" but as for a cause of the bank in the first place, does it sound reasonable for this to be caused by turbulence? 50 degrees of bank? at 35,000 ft.? 3 times?

Hey, I'm just a frequent flyer, not a pilot, but to me that sounds like something other than turbulance.

If the experts here lean towards turbulance, than I'm satisfied. Let's hear from you folks. what do you think?

[Edited 2008-01-13 15:17:04]
 
David L
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 11:32 pm



Quoting Gospelle (Reply 16):
to me that sounds like something other than turbulance.

Or something other than the turbulence you've experienced. Even though it might seem severe, most travellers never experience anything more than what the pros would call "moderate" - I certainly haven't. Severe turbulence has certainly downed a few aircraft in the past and damaged many more. Off-hand, I can think of a BOAC 707 that met such a fate:

http://www.aviation-safety.net/database/record.php?id=19660305-1
 
avioniker
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RE: Air Canada 190 - A319 Autopilot Failure?

Sun Jan 13, 2008 11:53 pm

And there was the Southbound L1011 that flew through the wake of an Eastbound 757 West of Sacramento in Dec'93. They had a number of injuries after the plane did some impressive aerobatics and lost 1300 feet.
I'm not sure if it did a roll or not.
 Smile
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
acabgd
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RE: Air Canada 190 - A319 Autopilot Failure?

Mon Jan 14, 2008 12:35 am



Quoting VC-10 (Reply 2):
What is the point of speculating? A complete waste of time

First of all, this is a discussion forum and not an NTSB hearing.

Quoting VC-10 (Reply 2):
any professional worth his/her salt would not guess at the cause.

Last time I checked this site was open to non-professionals as well and I try to respect them as well.

Furthermore, it's only normal to speculate when an incident/accident happens. It happens all the time here at a.net, so I really don't see why such a reaction from your part? Take it easy man, we're just talking...
CSud,D9,MD8x,D10,Trid,BAC1,A30,31,319,320,321,33,346,B71,72,73,74,75,76,77,L10,S20,A42,A72,T13,T15,F50,F70,F100,B146
 
gospelle
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RE: Air Canada 190 - A319 Autopilot Failure?

Mon Jan 14, 2008 12:35 am



Quoting David L (Reply 17):
Or something other than the turbulence you've experienced.

I understand this of course, but by the same token you have no idea what my experiences are. I really don't want to get off topic too much and drag this into a discussion about what people think vs. what is. instead, I'd really just like to know what would cause these symptoms. I think it's worth repeating. "Sudden, 50 degree Left roll, then right 35, repeated 3 times. then nothing.

It sounds mechanical. sorry it just does.

If it were turbulance, wouldn't the pilots have known it for what it was? Instead their statements to passengers seems to point in the other direction.
 
cptspeaking
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RE: Air Canada 190 - A319 Autopilot Failure?

Mon Jan 14, 2008 1:22 am



Quoting Gospelle (Reply 20):

Could be mechanical...but I think the more likely cause was CAT. Clear Air Turbulence is known to be very severe, and a roll of the airplane 50 degrees would kick the autopilot off. I know that when I'm talking to passengers, I dumb things down a lot. The majority of the flying public doesn't understand, much less care, what the autopilot's reaction to a sudden roll is. Telling the passengers "the autopilot had malfunctioned and we had to take control of the plane manually" seems to me a dumbed down version of "the severe turbulence we just encountered (and couldn't predict) caused a sudden roll past the 45 degree roll limit of the autopilot, causing it to shut off, so we had to start manually flying the airplane.

Also, I tend to not believe half of what passengers say, for exactly the same reason that we pilots dumb down our explanations of aviation-related happenings: the majority don't know what the heck they're talking about. When something like this happens, a 50-degree bank can easily seem inverted to a passenger.

Yes, air can do this. I've experienced it first-hand in the cockpit. I've also experienced extreme exaggeration by passengers, which can be even more exaggerated by the media looking for a dramatic story.

Your CptSpeaking
...and don't call me Shirley!!
 
Viscount724
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RE: Air Canada 190 - A319 Autopilot Failure?

Mon Jan 14, 2008 2:40 am



Quoting Gofly (Reply 7):
Quoting VC-10 (Reply 2):
What is the point of speculating? A complete waste of time when the facts are unknown, any professional worth his/her salt would not guess at the cause. Especially if the only eyewitnesses are passengers when it has been proved in the past they are prone to exaggeration

Exactly.

The only factual report I could come across was this one:

Please advise the website link for that report. I know where to find similar FAA and NTSB accident/incident summaries but have never been successful in finding a similar link for incidents in Canada (other than TSB accident reports when they are finally issued). Thanks for any info.
 
KensukeAida
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RE: Air Canada 190 - A319 Autopilot Failure?

Mon Jan 14, 2008 2:43 am



Quoting Acabgd (Reply 19):
First of all, this is a discussion forum and not an NTSB hearing.

Thank you.

This is the sanest thing I've read all day.  Smile

- John
 
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zeke
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RE: Air Canada 190 - A319 Autopilot Failure?

Mon Jan 14, 2008 1:24 pm



Quoting Gospelle (Reply 13):
I guess I'm relying on my own turbulence experience (lots) and the fact that the pilot came on the intercom afterwards and said they had an autopilot malfunction, computer out and had to fly manually. If there are any pilots reading who can tell me if a purely air effect could cause 3 repeated "Left" rolls of 50 degrees, kill a computer and autopilot, then I'll stand corrected.

Severe turbulence can do that, just ask any pilot to fly you through a developed thunderstorm at high level, they will all tell you where to go. Moderate/severe/extreme turbulence is not something pilots like to go near because you can loose effective control of the aircraft.

Moderate turbulence can be enough to disconnect an autopilot.

Quoting Gospelle (Reply 16):
If the reports of 50 degree bank is correct then I guess it could explain the A/P "knocking out" but as for a cause of the bank in the first place, does it sound reasonable for this to be caused by turbulence? 50 degrees of bank? at 35,000 ft.? 3 times?

The weather phenomena that is being suspected behind this event is called an atmospheric bore a wave like sharp change in pressure/temperature over shortish distances. Mountain wave activity was also in the area. The upper limit for this type of weather conditions is the tropopause, which varies with latitude, seasons, and pressure systems.

You cannot see this happening, for the pilots and passengers it would be like traveling down a nice smooth dirt road at night in a car with the lights off at high speed, then going over various deep wide pot holes for 15 seconds. The pot holes would cause the car to violently jump around side to side, and any steering wheel movements would feel like you are out of control, as you are, the force of hitting pot hole would be greater than what you could control via a steering wheel.

To give you an idea, this is the reporting criteria for severe and extreme turbulence:

Severe: Turbulence that causes large, abrupt changes in altitude and/or attitude. It usually causes large variations in indicated airspeed. Aircraft may be momentarily out of control. Report as Severe Turbulence. Occupants are forced violently against seat belts or shoulder straps. Unsecured objects are tossed about. Food Service and walking are impossible.

Extreme Turbulence in which the aircraft is violently tossed about and is practically impossible to control. It may cause structural damage. Report as Extreme Turbulence.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
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Starlionblue
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RE: Air Canada 190 - A319 Autopilot Failure?

Mon Jan 14, 2008 3:25 pm

Let me start by saying that this may well be a mechanical or electronic problem. But nothing that I have seen at this point excludes turbulence as the cause.

Quoting Gospelle (Thread starter):
In one case a passenger said she saw people hanging onto their armests to hold themselves in their seat and the armrests bent about 30 degres from the strain.



Quoting Gospelle (Reply 8):
The plane had rolled. So the armrests were being bent SIDEWAYS.

Where have you read that they were bent sideways? I agree with others that they probably just bent up. Pax misunderstanding or reporter editorializing? Pick one or both.

Quoting Gospelle (Reply 16):
If the reports of 50 degree bank is correct then I guess it could explain the A/P "knocking out" but as for a cause of the bank in the first place, does it sound reasonable for this to be caused by turbulence? 50 degrees of bank? at 35,000 ft.? 3 times?

Sure. Turbulence is nasty stuff and most flyers have never felt more than "light" turbulence.

Here is a "severe turbulence" definition I stole from a thread a while back.:

Severe Turbulence. Abrupt changes in aircraft attitude and/or altitude - aircraft may be out of control for short periods - usually, large variations in air speed - changes in accelerometer readomgs greater than 1.0g at the aircraft's centre of gravity - occupants are forced violently against seat belts - loose objects are tossed about.

Quoting David L (Reply 17):
Severe turbulence has certainly downed a few aircraft in the past and damaged many more. Off-hand, I can think of a BOAC 707 that met such a fate:

That was in Japan IIRC. There was also a Fokker in The Netherlands that came out of a storm cloud missing a wing.

Quoting Gospelle (Reply 20):
"Sudden, 50 degree Left roll, then right 35, repeated 3 times. then nothing.

It sounds mechanical. sorry it just does.

Where in a reliable report does it say "Sudden, 50 degree Left roll, then right 35, repeated 3 times. then nothing."? Sounds like a combination of eyewitness reports. In my experience if one non expert witnesses says "yes" and the other says "no", they're both wrong.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Pihero
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RE: Air Canada 190 - A319 Autopilot Failure?

Mon Jan 14, 2008 5:22 pm

This is what I wrote before the thread " Injured Passenger on Air Canada Flight " went dormant :
"A few comments, if I may, as I think we're going a bit overboard, here.



Clear air turbulence - CAT - if not easy to detect are in fact predicted with a good degree of certainty. A careful examination of a synoptic weather chart would give a pilot a fairly accurate knowledge of turbulent areas : Mountain waves, changes in the direction / altitude of a jetstreeam, convection...Before reaching these areas, switch the seat belts sign on and leave it on until clear of the area. Half of the times, nothing will happen but one in ten, the turbulence can be very uncomfortable and in a very few times, like this one, it can be severe.
Please note that the severity of that sort of turbulence depends very much on one's route relative to the wind / waves / rollers...
The cabin crew should be advised that - for instance - at 21.45 hrs, we're likely to be in some bumpy air and would they please make sure that at that time, there won't be any service and the galleys will be secure. If at 21.55, we're still in calm air, I'd still resist any demand from the F/As to switch the sign off.
It saved me a few injuries.
Of course, there are the odd instances where the turbulence comes *from nowhere*, that's why it's a good idea to keep one's belt fastened.


Storm-related turbulence : A good radar watch discipline and avoidance should take care of it. Sign on still...


Autopilots : Like everything, they have their design limits, beyond which George is going to cross his arms and say : "You have control "...I hope you're trained for that event.


There have been some comments about the dumbed-down vocabulary of the pilots on PA. Difficult to be too technical so the "...autopilot had been knocked out...we' re flying manually..." fulfills the requirement of reassuring the passengers. It has never been meant to be the meat for some journalists, but that's one of the aspects of the job that we have come to live with.
"

Instances of injured aircrews and passengers abound. They are not generally published on the international press and go unnoticed apart from a few people in the country.
Contrail designer
 
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HAWK21M
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RE: Air Canada 190 - A319 Autopilot Failure?

Tue Jan 15, 2008 7:07 am

Any Regulatory Body report published yet?
Also how is the A/P on the A319 like.how many A/Ps are there installed totally?

regds
MEL.
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gospelle
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RE: Air Canada 190 - A319 Autopilot Failure?

Tue Jan 15, 2008 7:29 am

To the person who asked: From the definitions presented for severe and extreme turbulance I would say I have been in severe turbulance at least 3 times. (once was a clear air event) I do not think I have ever been in "extreme" turbulance.

From the mood of all the posts, I would say you're all convinced this is simply a turbulence event and that passengers are all stupid or ignorant and can not be depended on for an accurate portrayal of something even if it was witnessed by their own eyes. I suppose smart people and those prone to keen observation must take the bus.

If CptSpeaking says he's (she's?) seen this type of loss of control first hand then I guess it's very likely this was turbulence.

Personally, I'd rather not fly on that particular plane until the report comes out. Speaking of which, anyone know what the fin # was on that plane?

[Edited 2008-01-14 23:37:26]

[Edited 2008-01-14 23:39:27]
 
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Starlionblue
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RE: Air Canada 190 - A319 Autopilot Failure?

Tue Jan 15, 2008 7:46 am



Quoting Gospelle (Reply 29):

From the mood of all the posts, I would say you're all convinced this is simply a turbulence event and that passengers are all stupid or ignorant and can not be depended on for an accurate portrayal of something even if it was witnessed by their own eyes. I suppose smart people and those prone to keen observation must take the bus.

I wouldn't say that. Given the lack of information, the most likely even is turbulence. This doesn't rule out an aircraft problem.

Passengers, even those not stupid and ignorant, are not reliable witnesses, "with their own eyes" or not. Ask any policeman or professional investigator. Eyewitness accounts are notoriously unreliable since they are inevitably tainted by the experiences and analysis of the observer. Most observers are not subject matter experts, and what they think they know "damages" the evidence they can submit. It is quite easy to fool the mind into thinking it sensed something when what actually happened was quite different. Fear will of course make things worse.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
PhilSquares
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RE: Air Canada 190 - A319 Autopilot Failure?

Tue Jan 15, 2008 7:51 am

Quoting Gospelle (Reply 29):
To the person who asked: From the definitions presented for severe and extreme turbulance I would say I have been in severe turbulance at least 3 times. (once was a clear air event) I do not think I have ever been in "extreme" turbulance

While you might think it was severe turbulence, I rather doubt it. Moderate maybe but severe???

Quoting Gospelle (Reply 29):
From the mood of all the posts, I would say you're all convinced this is simply a turbulence event and that passengers are all stupid or ignorant and can not be depended on for an accurate portrayal of something even if it was witnessed by their own eyes. I suppose smart people and those prone to keen observation must take the bus.

I think you're taking this too personally! People in the cabin have no idea of altitude lost or airspeed fluctuations. Just like they don't have any idea of airspeed on touchdown while sitting in the cabin. No one has accused anyone of being "stupid", it's just there is no frame of reference while one is sitting in the cabin.

Quoting Greasespot (Reply 11):
Speculating gives people something to talk about. Are we supposed to just ignore a major event until the report comes out in a few years... I am/was a professional and we did it all the time at work...It is part of the human condition..It is called curiosity.

There is nothing wrong with speculation, however speculation without any facts is just guessing. That's not speculation, it's not even an informed guess, it's a shot in the dark.

Personally, from what I've read and the figures I've seen, there's no doubt in my mind it was a turbulence event that resulted in the autopilot being disconnected and a resultant partial loss of control. To be honest with you, I'd have no problems getting on the same aircraft.

FYI....if you want or enjoy "speculation" as you wrote, perhaps you might be better off posting this in the Civ Av forum. This is the Tech forum where people tend to form opinions based on facts.

[Edited 2008-01-14 23:53:15]
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David L
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RE: Air Canada 190 - A319 Autopilot Failure?

Tue Jan 15, 2008 12:39 pm



Quoting Gospelle (Reply 29):
From the mood of all the posts, I would say you're all convinced this is simply a turbulence event

Nobody's saying it definitely was turbulence, just that it's likely. The disagreement is over your apparent assertion that it could not have been turbulence.

Quoting Gospelle (Reply 29):
and that passengers are all stupid or ignorant and can not be depended on for an accurate portrayal of something even if it was witnessed by their own eyes. I suppose smart people and those prone to keen observation must take the bus.

Let's not be silly about it.  Smile
 
cptspeaking
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RE: Air Canada 190 - A319 Autopilot Failure?

Tue Jan 15, 2008 2:38 pm



Quoting Gospelle (Reply 29):
I would say you're all convinced this is simply a turbulence event and that passengers are all stupid or ignorant and can not be depended on for an accurate portrayal of something even if it was witnessed by their own eyes.

It's not that they're stupid or ignorant, but stupid and ignorant. Just kidding...  biggrin  ....sort of....

In all seriousness, passengers generally have no experience flying an airliner to base their opinions of events on. Private Pilots who fly Cessnas on weekends don't count either. Most people have driven a car, so they are more qualified to offer their commentary on what happened in a bus accident, simply because they know from their experiences what can happen on the road to cause certain feelings and outcomes.

Airplanes are a whole different animal because of several reasons. Your perceptions are limited severely when you're so far away from any visual reference at cruise altitude. 120 mph in your car looks really fast because you're (hopefully) right on the road, but in your Cessna, it looks incredibly slow because you're generally over a mile from what you're perceiving speed based on. It's even worse in an airliner, with exponentially more variables.

Also, without being able to see out the front of the airplane, it is very hard for anybody to accurately give an account of the bank angle of the plane. Looking out the side isn't much help because your mind will base it's judgement of bank angle upon how far the wingtip is from the horizon. Problem with that is that with a change in wingspan, the tip will move more in a given bank, which means that what looks like 30 degrees in your Cessna is probably barely 15 in an Airbus.


So it's not that I think all passengers are stupid and ignorant, it's just that from their vantage point, it is very difficult to give an accurate account of what really happened, especially when there is no raw data to base this account on, but rather just feelings. That and the fact that passenger accounts are generally sensationalized for dramatic effect, and even more so when they talk to the media, who in turn exaggerates it even more...you get the picture.

This whole thing sort of reminds me of the story about the guy with the altimeter watch who threatened to report the Captain to the FAA because they had to have been going way more than 250 kts and were never higher than 8000 feet!!  biggrin  (Case in point...  Wink )
...and don't call me Shirley!!
 
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Starlionblue
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RE: Air Canada 190 - A319 Autopilot Failure?

Tue Jan 15, 2008 3:44 pm



Quoting CptSpeaking (Reply 33):
This whole thing sort of reminds me of the story about the guy with the altimeter watch who threatened to report the Captain to the FAA because they had to have been going way more than 250 kts and were never higher than 8000 feet!! biggrin (Case in point... Wink )

There's nothing quite like the person with juuuust enough knowledge and information to be dangerous. Kind of like my mother used to be with computers before she figured them out.  Wink
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Arrow
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RE: Air Canada 190 - A319 Autopilot Failure?

Tue Jan 15, 2008 3:58 pm



Quoting CptSpeaking (Reply 33):
his whole thing sort of reminds me of the story about the guy with the altimeter watch who threatened to report the Captain to the FAA because they had to have been going way more than 250 kts and were never higher than 8000 feet!!

That's funny. I have an altimeter watch I use for back country hiking and skiing. And yes, I enjoy watching it wind up and wind down when I'm flying commercial. My best experience was on take off once watching it drop to about 1500 feet below sea level before the pressurization stabilized and it started moving up. I always wondered why that happened.
Never let the facts get in the way of a good story.
 
avioniker
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RE: Air Canada 190 - A319 Autopilot Failure?

Tue Jan 15, 2008 4:26 pm



Quoting Arrow (Reply 36):
My best experience was on take off once watching it drop to about 1500 feet below sea level before the pressurization stabilized and it started moving up. I always wondered why that happened.

That's how the pressurization system is supposed to work, in a Douglas at least.

For instance, on a DC-10, the outflow valves close and the cabin is pressurized to .125psi higher than ambient as soon as the throttles are pushed up for takeoff. The system then holds the airfield altitude until the aircraft passes through 5000ft. That's so that if the plane has to return to the runway the crew and passengers don't have to deal with popping ears and the resultant loss of hearing that goes with it.

On descent and landing the pressurization system gradually decreases the cabin altitude so that it's 200 feet below the landing field altitude when the plane reaches about 5000ft above ground. It then slowly raises the cabin altitude until, at landing, the cabin altitude is the same as the outside. Once again it's for passenger comfort but also to allow the pilots to fly the aircraft without having to keep grabbing their noses to equalize their inner ears so they can hear the radios.

The newer aircraft are interfaced with the FMS to do the same thing.

Long story short, your watch reflected that the aircraft pressurization system was functioning properly.

 Smile
One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
 
tdscanuck
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RE: Air Canada 190 - A319 Autopilot Failure?

Tue Jan 15, 2008 6:17 pm



Quoting HAWK21M (Reply 28):
Also how is the A/P on the A319 like.how many A/Ps are there installed totally?

On an A319 (and any FBW Airbus) the A/P isn't a separate function, it's just a feature riding on top of the FBW system. So I'm not sure that an Airbus has a particular number of autopilots, it's more the level of redundancy in the FBW system. The autopilot and sidestick are both inputs to the FBW system, which decides what to actually do with the control system based on those (and several other) inputs. This is very different than the Boeing-style autopilot, which is basically a "mechanical pilot" moving the controls just like a human, although it's hooked in at a different point.

Quoting Gospelle (Reply 29):
I would say you're all convinced this is simply a turbulence event and that passengers are all stupid or ignorant and can not be depended on for an accurate portrayal of something even if it was witnessed by their own eyes.

I join those above who don't think the passengers are stupid or ignorant, but may not be providing accurate information (not through malicious intent, but normal factors). The event, as reported so far, is consistent with turbulence. Turbulence is *far* more common than failure of a FBW control system, so I'm hedging my bets with turbulence until evidence suggests otherwise.

Tom.
 
gospelle
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RE: Air Canada 190 - A319 Autopilot Failure?

Wed Jan 16, 2008 4:51 am

Quoting CptSpeaking (Reply 33):
In all seriousness, passengers generally have no experience flying an airliner to base their opinions of events on. Private Pilots who fly Cessnas on weekends don't count either. Most people have driven a car, so they are more qualified to offer their commentary on what happened in a bus accident, simply because they know from their experiences what can happen on the road to cause certain feelings and outcomes.

Airplanes are a whole different animal because of several reasons. Your perceptions are limited severely when you're so far away from any visual reference at cruise altitude. 120 mph in your car looks really fast because you're (hopefully) right on the road, but in your Cessna, it looks incredibly slow because you're generally over a mile from what you're perceiving speed based on. It's even worse in an airliner, with exponentially more variables.

Which is all completely irrelevant because you don't have to be a plane expert to know that when a person flys up and hits the ceiling that it actually happened. Or bent an armrest, or that the plane flipped to one side 3 times. According to your level of thinking someone would have to be an expert in physics for you to belive (maybe) that the armrest actually bent, because the average joe couldn't possibly know what bending something actually looks like.

Given the expert oppinions here, I am fine saying that it may in fact be an extreme turbulence event. But I don't see how the similar reports of hundreds of people can be dismissed so easily just because they're not experts in aviation.

[Edited 2008-01-15 20:58:14]
 
cptspeaking
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RE: Air Canada 190 - A319 Autopilot Failure?

Wed Jan 16, 2008 5:21 am



Quoting Gospelle (Reply 40):
ou don't have to be a plane expert to know that when a person flys up and hits the ceiling that it actually happened. Or bent an armrest, or that the plane flipped to one side 3 times

The plane flipping to one side sure sounds EXACTLY like the situation I described...passengers reporting the plane on its side when it actually isn't...I don't have any problem with the passenger's accounts of things happening in the cabin, but what I do think is hard to believe is the accounts of what the airplane itself is doing...see the difference?

Quoting Gospelle (Reply 40):
But I don't see how the similar reports of hundreds of people can be dismissed so easily just because they're not experts in aviation.

I'm not dismissing them, just suggesting that they're not entirely correct and usually exaggerated. By no means am I an "expert", but I do have more experience in the front than most frequent flyers, and I wouldn't trust my own perceptions of what was happening if I was sitting in the cabin. It's all to do with the fact that in the back, you don't have access to all the flight instruments that you do up front which give you accurate information.

Armrests bending and people hitting their heads are valid facts...reporting a 90-degree bank and a loss of 5000 feet from seat 15E aren't...
...and don't call me Shirley!!
 
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Starlionblue
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RE: Air Canada 190 - A319 Autopilot Failure?

Wed Jan 16, 2008 6:39 am



Quoting Gospelle (Reply 39):
I don't know how you can make a comment like that. How do you know what my experiences are? To just post that someone is a liar is a rude thing to do. What do you want flight numbers? good grief! I gain nothing by coming on here and over exagerating my personal experiences. Had I known I'd be questioned later in life as to the truthfulness of my accounts I'd have written down the names of the pilots, but you know, that just seems like a silly thing to do. I read the descriptions and those matched my experiences. If you're lucky enough to have gone your whole life without a major turbulence event then count yourself lucky. I personally seem to be plagued by "interesting" flights.

< rant >
I will expand on what others said. I think you might want to consider chilling out a bit. Your reactions are way out of proportion to the responses you got. You were told you were probably wrong by subject matter experts and now you're yelling at them for stating their opinions.

Some people here are very direct and it may seem like a personal attack when they take apart some statement you made and stomp on it for good measure. But it is almost never a personal attack. They aren't attacking you, they're just giving their opinion of your statement without sugarcoating it. (At this point I'll note that since you posted you implicitly invited comment). Some people are just that way, direct and to the point. I have also found the same people you are taking issue with to be extremely helpful and informative if approached with a minimum of politeness.

I have been told that I am totally wrong on this forum more times than I can count. That's ok, because most of those times I was in fact totally wrong. I try to learn from my mistakes. When I don't learn I trust the pros to stomp on me and my opinions the way I deserve.
< /rant >
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
TrijetsRMissed
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RE: Air Canada 190 - A319 Autopilot Failure?

Wed Jan 16, 2008 7:00 am

I have been on a flight (UA 752) that hit severe turbulence, went into a brief twisting dive, and eventually regained control before landing. There were injuries on board and we landed shortly. What raises my curiousity about this situation is that the aircraft roll left and right, back and forth. Granted the autopilot systems of a 752 and A319 are different.

Quoting VC-10 (Reply 2):
What is the point of speculating? A complete waste of time when the facts are unknown,

I hate to break it to you, but from the point an incident is reported the NTSB begins speculating. It's called brainstorming. Sure, they don't jump to conclusions, or tell the public an incorrect theory ala AA 191, but they don't stand pat either.

Quoting Gospelle (Thread starter):
In one of the 737 cases where the plane recovered and landed, there is mention of the autopilot as well (Continental April 11, 1994 in Honduras).

Sounds like the Eastwind 732 inflight rudder incident on the east coast in '96. Could be unrelated, however.

Quoting Tdscanuck (Reply 5):
Armrests are hinged upward...how you use them to hold yourself down?

The aircraft was not inverted.

Quoting Gospelle (Reply 9):
In a fly by wire A319 would the pilots be "fighting" with controls which would cause a sudden opposite roll if a locked PCU "let go"?

This entered my mind as well. It could have nothing to do with it, but given by the pilots reports, and the few incidents that happened the late 80's, early 90's, it's not outside the realm of possibility.

Quoting SPREE34 (Reply 10):
Obviously not turbulence? What makes it obviously not turbulence?

If the pilot indeed said, "the autopilot has malfunctioned and we had to take control of the plane manually," then that would indicate there may be more to the story.
There's nothing quite like a trijet.
 
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zeke
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RE: Air Canada 190 - A319 Autopilot Failure?

Wed Jan 16, 2008 8:38 am



Quoting Gospelle (Reply 39):
Just because YOU have been lucky doesn't make me a liar.

No one is calling you a liar, bit if people who have flown A320 series aircraft take the time out to share some of our experience with you (like PhilSquares, Pihero and myself), please don't dismiss it.

We have to deal with a lot worse than what you have experienced every few months in the simulator, what seems dramatic to you, to us is somewhat of a non event to us. The only thing we would dread is the paperwork that follows real life events.

I am still of the view this was a turbulence related event, unless the DFDR shows otherwise, but as far as I am aware that is not what was seen after the initial download. FYI prior to this event, the aircraft had been hunting levels looking for a smooth ride.

The other telling factor for me is whenever a significant event occurs the manufacturer gets involved, and when Airbus gets involved, they are pretty quick to send a telex to all operators to update them on the event. Nothing has been sent out, which again is some more circumstantial evidence that it was not related to the aircraft systems.

Quoting TrijetsRMissed (Reply 45):
"the autopilot has malfunctioned and we had to take control of the plane manually,"

I saw that line in the press, but as far as I am aware it is not a direct quote, the CVR should clear that up. I think all the pilot was trying to convey was that they were unaware of what had caused the autopilot to disconnect, and since it disconnected they needed to fly the aircraft manually.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
Pihero
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RE: Air Canada 190 - A319 Autopilot Failure?

Wed Jan 16, 2008 9:03 am

Gospelle :... "I read the descriptions and those matched my experiences. If you're lucky enough to have gone your whole life without a major turbulence event then count yourself lucky. I personally seem to be plagued by "interesting" flights"...

This is a rather interesting list of turbulence-related injuries on-board.
Please take some time going through them. An interesting point is that a lot of these injuries happened on events categorised as moderate.
Another point is that, funny enough, appreciations from the F/As and passengers side generally differ from those of the flight-deck crews. (It's not only a matter of appreciation, but also of reporter's position in the aircraft ).
Here is the link

Quoting Zeke (Reply 41):
The other telling factor for me is whenever a significant event occurs the manufacturer gets involved, and when Airbus gets involved, they are pretty quick to send a telex to all operators to update them on the event. Nothing has been sent out, which again is some more circumstantial evidence that it was not related to the aircraft systems.

 checkmark   checkmark 
I had been waiting for one, too !
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Starlionblue
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RE: Air Canada 190 - A319 Autopilot Failure?

Wed Jan 16, 2008 12:04 pm



Quoting Zeke (Reply 41):
The other telling factor for me is whenever a significant event occurs the manufacturer gets involved, and when Airbus gets involved, they are pretty quick to send a telex to all operators to update them on the event.

Off topic but do they actually still use telex?
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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zeke
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RE: Air Canada 190 - A319 Autopilot Failure?

Wed Jan 16, 2008 12:25 pm



Quoting Starlionblue (Reply 43):
Off topic but do they actually still use telex?

We still have heaps of them floating about at work, they are still widely used in the industry. The Operator Information Telex (OIT), All Operators Telex (AOT). and Flight Operations Telex (FOT) I see now normally come by fax and email.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
PhilSquares
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RE: Air Canada 190 - A319 Autopilot Failure?

Wed Jan 16, 2008 1:43 pm



Quoting Gospelle (Reply 37):
Given the expert oppinions here, I am fine saying that it may in fact be an extreme turbulence event. But I don't see how the similar reports of hundreds of people can be dismissed so easily just because they're not experts in aviation.

Since your post was deleted that accused everyone of calling you a liar I will attempt to redress your concerns.

There are several professional, knowledgeable commercial pilots on this fourm who spend a great deal of their lives in the sky. Those pilots and myself have made the statement we feel the cause of the upset was turbulence related. In fact, we also stated your claims of "extreme severe" turbulance was overstated. You might want to consider stepping away from this thread for a day or so. See what happens and then come back and make a post.

Quoting Gospelle (Reply 8):
I am not a professional, so I have no "salt". I WANT to speculate. That's the whole point of my thread. Of course passengers exagerate, but based on several reports, a "theme" can be seen. one of which is that the plane had a severe and sustained "roll". that is obviously NOT turbulence. So if we all concede that, then let's speculate a bit. What WOULD cause a severe and sustained roll?

While you might want to speculate, most professional pilots I know will reserve any type of judgement until they have ample facts. This fourm tends to follow the same protocol. It accomplishes nothing to make "WAGS" on here and it's just a waste of time. By your own admission, you are not a professional, then you must be a passenger. Everyone has, quite politely I might add, told you it's virtually impossible to judge, altitude, speed, distance from the passenger cabin, but you just don't seem to want to accept that fact.

You have really tried to make this incident a major event. It's not! Pilots are trained for things like this. You have stated you have experienced "severe" turbulence, I rather doubt it. I don't know of too many pilots who would drive through reported or forcast areas of severe trubulence.
Fly fast, live slow
 
tdscanuck
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RE: Air Canada 190 - A319 Autopilot Failure?

Wed Jan 16, 2008 5:48 pm



Quoting TrijetsRMissed (Reply 40):
Quoting Tdscanuck (Reply 5):
Armrests are hinged upward...how you use them to hold yourself down?

The aircraft was not inverted.

That was a direct response to this:

Quoting Gospelle (Thread starter):
In one case a passenger said she saw people hanging onto their armests to hold themselves in their seat

You don't need to hold yourself up in the seat (that's what your rear end is for) and you don't need to hold yourself sideways (that's what armrests do just by being there) so I assumed that "hanging onto their armrests to hold themselves in their seat" was a reference to holding themselves down.

Quoting Starlionblue (Reply 43):

Off topic but do they actually still use telex?

Like Zeke, we still had tons of them floating around until a massive cleaning effort about 9 months ago when we got rid of everything that we already had online elsewhere. Today, first method is email, followed by fax, followed by telex, followed by print-and-mail. Every operator has a preferred way to be contacted but about 99% of them are email now...I do maybe one fax every couple of months.

Tom.
 
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longhauler
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RE: Air Canada 190 - A319 Autopilot Failure?

Thu Jan 17, 2008 12:11 am



Quoting Zeke (Reply 41):
I am still of the view this was a turbulence related event, unless the DFDR shows otherwise, but as far as I am aware that is not what was seen after the initial download.

I have to agree. From the initial reports it "sounds" like turbulence. Attitudes exceeded enough to knock off the autopilot, allowing the pilots to bring the aircraft back to safe control. I flew a flight into YLW that day, (about 100 miles north of where the incident occurred), and the turbulence was continuous moderate! No smooth altitudes. The winds aloft went from west at 13 knots, to north west at 155 knots in 30 miles! That will NOT be smooth!

However, I also agree because of what I have NOT heard. Namely within Air Canada. There have been no procedure changes with respect to SOPs, as well as aircraft handling. Further, there have been no warnings with regard to aircraft malfunctions. This leads me to believe there was not an aircraft malfunction ... and ... the pilots acted properly. Rest, assured, by now, internally, it would be known by now if there was anything untoward.
Just because I stopped arguing, doesn't mean I think you are right. It just means I gave up!
 
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Starlionblue
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RE: Air Canada 190 - A319 Autopilot Failure?

Thu Jan 17, 2008 12:50 am



Quoting LongHauler (Reply 47):
Further, there have been no warnings with regard to aircraft malfunctions.

If I may take this into the purely hypothetical for one moment, could we focus on this a bit? I am struggling with how exactly it helps pilots beyond a purely informational aspect.

Let's assume the flight control system was thought to be a possible cause of a hypothetical malfunction. I understand the need to warn pilots about the fact that there may be an aircraft malfunction. But what exactly would this kind of warning mean for pilots. "The flight control system may suddenly initiate an uncommanded series of rolling movements. Watch it." How much good does this do? That is, would knowing about the possibility help in itself? Would there be a proposed plan of action? Does all this depend?
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
abnormal
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RE: Air Canada 190 - A319 Autopilot Failure?

Thu Jan 17, 2008 1:12 am



Quoting Starlionblue (Reply 48):
would knowing about the possibility help in itself? Would there be a proposed plan of action? Does all this depend?

Yes it would. If you have prior knowledge of a spurious malfunction or equipment anomaly then then when it does actually happen you don't have to troubleshoot as much or fight the aircraft computers.

The first time it happens in service can be pretty exciting for the crew involved. Afterwards the anomaly gets reported to the manufacturer's, they investigate, and where appropriate issue an advisory bulletin.

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