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Pihero
Posts: 4318
Joined: Mon Jan 31, 2005 5:11 am

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 9:07 pm

Quoting zeke (Reply 289):
Trim can easily be overcome with rudder pedal input by the pilots at any time.

I am not so sure as it reduces the deflection to the other side... and with the rudder travel limited to 3.5 to 5°, I'm even less sure.
Have you tried it, Zeke ?

I've asked some friends to try it on the sim.

Quoting hivue (Reply 296):
I think people are getting really confused here.

We concentrated on the rudder as the aircraft was - in all appearances - in a wide - ish - spiral to the left.
BVut one has also to have a look at Mandala499's post :
ELAC 1 FAULT
... ELAC2, and FAC2 swap
and then you have mel'd : FAC 2 FAULT

ELACs : Elevator / aileron computers are for Normal elevator / stabilizer and aileron control...

Do you see where all this could lead to ?
But - big But - it needs a major failure or cascade of failures to start explaining the apparent airplane behaviour.
Contrail designer
 
LTC8K6
Posts: 1590
Joined: Fri Jun 05, 2009 8:36 pm

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 9:41 pm

"On the Airbus, all that remains of the traditional control method is a cable system for controlling the rudder and trim systems on the tail, which would allow the plane to land safely even if all of its electrical systems failed. "

http://www.nytimes.com/1988/06/29/bu...the-a320-s-fly-by-wire-system.html

Is that no longer true? Or is it wrong?
 
hivue
Posts: 2126
Joined: Tue Feb 26, 2013 2:26 am

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 9:44 pm

Quoting Pihero (Reply 301):
But - big But - it needs a major failure or cascade of failures to start explaining the apparent airplane behaviour.

Understood. My reading of the AAIB report you posted earlier is that if there is a rudder trim fault as a result of electrical issues there still are protections in place to keep the trim from running away to the point where the airplane is no longer controllable.
"You're sitting. In a chair. In the SKY!!" ~ Louis C.K.
 
AIRWALK
Posts: 241
Joined: Fri Jun 06, 2014 9:33 am

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 9:47 pm

Quoting LTC8K6 (Reply 302):

"On the Airbus, all that remains of the traditional control method is a cable system for controlling the rudder and trim systems on the tail, which would allow the plane to land safely even if all of its electrical systems failed. "

From what I know there is a mechanical law backup mode which can control the rudder mechanically.
I'm sure this thread will take off soon
 
rusti999
Posts: 20
Joined: Tue Jun 03, 2008 5:56 pm

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 9:52 pm

Quoting md80fanatic (Reply 275):
It was hoped that most of the missing 108 people would be found inside the fuselage section, by the sound of this latest report that number will need to be lowered ... to 15 or less.

I think there are more bodies inside the fuselage. But as a scuba diver myself, I know it won't be a straightforward exercise for divers to go inside the fuselage and retrieve the bodies, there will be risks of entanglement, and in 30-40 meters of water, with typical open-circuit scuba equipments (not sure if they have more sophisticated equipments, such as a rebreather, I haven't seen any pictures indicating they do), each diver can stay at the bottom for 15-20 minutes before having to ascend.

Quoting md80fanatic (Reply 275):
If diving conditions are favorable, enabling entry into the fuselage section and the recovery of passengers, then it follows that submersibles would find the conditions favorable for photography as well. I can't help but wonder ... why no new images, one of the "cockpit" and at least one of the detached engine?

The images of the main fuselage were obtained using a submersible owned by the Singapore military. However, at this point, all foreign assistance has ended, so now the effort is carried out by Indonesian authorities without any assistance by other countries. I'm not sure if Indonesia has such a submersible.

[Edited 2015-01-23 13:58:10]

[Edited 2015-01-23 14:06:45]
 
joejosh999
Posts: 65
Joined: Fri Jan 23, 2015 4:01 pm

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 10:24 pm

In my past jobs I've been trained to pay extra attention when points are strenuously denied as in the post above....
It seems odd that the potential for rudder issues, which our Mandela mentioned and have been supported here with incident reports and YouTube videos should be so vehemently discarded.

Unfortunately I cannot question these posts as Pprune has banned me.
 
maxpower1954
Posts: 1067
Joined: Thu Sep 25, 2008 1:14 am

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 10:34 pm

The A320 does have mechanical back up control of the rudder, but it's not manual reversion in the conventional sense. In case of total electrical failure, the cables move the hydraulic actuators instead of the FBW servos. You still need hydraulics to move the rudder. The stabilizer trim uses the same type back up system..

Russ Farris
 
AirBoat
Posts: 70
Joined: Sun Jan 18, 2015 11:58 am

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 11:04 pm

Looking at the blue illustration of the track:
It would be interesting to know what happened between points 2 and 3.
From what I could read up, the data on the recorder is sampled a few times per second.
The constantly reducing speed , whether the plane was going up or down, seems to indicate loss of pitch control,
for whatever reason.
It would be interesting to know, when the speed started reducing
 
Thai77w
Posts: 371
Joined: Sun Mar 30, 2014 10:56 am

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 11:28 pm

I just arrived in KL on MH134 from Brisbane and we flew directly over the crash site. I was in J class and our inflight supervisor and several flight attendants gathered in the front galley as we flew over and said a small prayer for the victims.

I was quite touched by this, and moved me quite a bit. They obviously know what its like with the recent tragedies, having first hand experience.  
Aircraft types I've been on: PA31,Q300,AT75,AT76,717,733,738,739ER,763,772,77E,773,77W,788,789,744,319,320,332,333,346,359,380
 
joejosh999
Posts: 65
Joined: Fri Jan 23, 2015 4:01 pm

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 11:28 pm

So sorry!!! Many apologies!!
MANDALA.
All due respect!
 
User avatar
EK413
Posts: 5645
Joined: Sat Nov 29, 2003 3:11 pm

RE: Air Asia QZ8501 SUB To SIN Crash - Part 12

Fri Jan 23, 2015 11:31 pm

Hi All,

With the current thread well beyond 300+ responses and difficult to keep track of responses please continue discussions here Air Asia QZ8501 SUB To SIN Crash - Part 13 (by EK413 Jan 23 2015 in Civil Aviation)

EK413
Good evening, ladies and gentlemen. We are tonight’s entertainment!
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