News Air Asia flight QZ8501 missing

[C3PO]

I think that may only apply to fighter planes which are inherently unstable, unflyable even, to gain the upper hand in manoeuvrability. Airliners are supposed to be stable, and want to fly - FBW stops the crew ripping the wings off or getting outside the airframe's envelope.

FBW is by definition flying without direct (mechanical or hydraulic) connection between input and output. Shutting down the link between input and output leaves you with NO control.
By the time you need a FBW reset you are most likely not in level flight and you need to take immediate action to avoid disaster. Not the best time to sit and wait for the electronic to get its ducks in a row.

 

[TachyonDriver]

Ah, I see what you mean

 

[garyw]

That sounds like the dumbest piece of design since male nipples.

I am in error, it's a CB and not a flight deck switch.

 

[Urwumpe]

I am in error, it's a CB and not a flight deck switch.

Yeah - with CBs you can try to turn every computer off and on again. :lol:

 

[Urwumpe]

The NTSC of Indonesia has published their report on the accident, there are some strong parallels to the AF440 accident: The copilot pulled the aircraft up, when the pilot ordered him to pull down.

http://kemhubri.dephub.go.id/knkt/ntsc_home/ntsc.htm

 

[fred18]

The NTSC of Indonesia has published their report on the accident, there are some strong parallels to the AF440 accident: The copilot pulled the aircraft up, when the pilot ordered him to pull down.

http://kemhubri.dephub.go.id/knkt/ntsc_home/ntsc.htm

I gave it a look... how is that possible that it's enough to have a panicked co-pilot who simply keeps trying to pull up when stall happens and kills everybody...

first of all pilots and copilots should be trained for this situations, if they react like every simple passenger in case of danger and they simply panic then what's the point.....

second even if they panic and they keep trying to pull up there should be a way for pilot to avoid this... I think that on this subject fly by wire is worse than before, since before pilot and copilot had the sticks that could only be moved in the same way and it was easier to notice if anything was wrong...

That happened twice already, I think it's a bit frightening...

 

[Urwumpe]

I gave it a look... how is that possible that it's enough to have a panicked co-pilot who simply keeps trying to pull up when stall happens and kills everybody...

first of all pilots and copilots should be trained for this situations, if they react like every simple passenger in case of danger and they simply panic then what's the point.....

second even if they panic and they keep trying to pull up there should be a way for pilot to avoid this... I think that on this subject fly by wire is worse than before, since before pilot and copilot had the sticks that could only be moved in the same way and it was easier to notice if anything was wrong...

That happened twice already, I think it's a bit frightening...

Yes, it is actually massive human error. It is a Dual Input situation again and again the pilot side stick shows correct response (or fighting the inputs of the copilot), the copilot keeps the stick pulled full back.

But if not: I wonder if there could be some kind of software malfunction regarding the copilot stick, wrongfully registering the input as full back, even if the copilot does not touch the stick.

 

[Ravenous]

On initial reading of the conclusions, the report seems to describe a whole set of events, from a solder crack in the rudder system causing distracting warnings, to the two pilots getting confused about recoveries.

All the above is taken from the report by the way:
http://kemhubri.dephub.go.id/knkt/ntsc_home/ntsc.htm

Oh well...

 

[mojoey]

Firstly, your lack of CRM is disturbing, Asia. Fix it.

Secondly, if the FO had stalled the aircraft in a panic, wouldn't the A-Floor protection mode kick in and command a lower pitch attitude automatically?

 

[Urwumpe]

Secondly, if the FO had stalled the aircraft in a panic, wouldn't the A-Floor protection mode kick in and command a lower pitch attitude automatically?

Not in alternate law (Airbus, remember) and alternate law was activated because of the (unsafe) computer reset.

 

[mojoey]

Ah yes, the wonderful world of Airbus logic. Logic that can get you killed because 'muh safety'.

 

[Urwumpe]

Ah yes, the wonderful world of Airbus logic. Logic that can get you killed because 'muh safety'.

Well, in most cases, it does indeed save lives. Just look for example at the accident rates of non-FBW planes like the 737 or the less numberious, alternative 777, which follows a more conservative FBW design (Please ignore FBW problems caused by Russian SAMs).

Also, the big issue there is the FAC 2 reset, which required the captain to leave his seat and reach behind the copilot to pull the circuit breakers. That has been an action, that can only be done on the ground especially because it really makes the FBW mad.

The reaction of the copilot is understandable in primary law (he wants a maximal positive acceleration, so he pulls up as much as possible), but it is a wrong practice, since even in a stall, you should either get your hands off the sidestick or pull the nose down just like on any other plane.

There are claims about pulling up being part of Airbus training, but I can't find any verification for this. There is no FBW jet where the manual is not recommending lowering the nose.

In most cases, the pulling up is explained either by panick or by bad training, just like a video game noob would make an approaching stall worse by pulling up against all the laws of aerodynamics.

 

[mojoey]

Did the rumor mention from Airbus itself, or a company with an airbus fleet? Either way it makes no sense. The crew would be more than capable of putting the throttles to MCT and lowering the nose on their own, normal law's babysitting is only for when you spazz out.

 

[Urwumpe]

Did the rumor mention from Airbus itself, or a company with an airbus fleet? Either way it makes no sense. The crew would be more than capable of putting the throttles to MCT and lowering the nose on their own, normal law's babysitting is only for when you spazz out.

Exactly. It also makes sense if nature gets a bit aggressive to you, since the normal law protections react much faster than any human can.

 

[MaverickSawyer]

So, another case of the crew being systems managers, not pilots... :dry:

 

[Urwumpe]

So, another case of the crew being systems managers, not pilots... :dry:

As if you can today drive a car without also learning about its behaviour first. Especially ESP equipped cars can badly ruin your day if you get into road conditions in which the ESP has the opposite effect. And if you are not knowing that you have to disable the start-stop system before you drive into a car wash, you might not enjoy it.